Saroj's Blogs

AVSpeechSynthesizer example iOS7

2014-05-08T11:41:00.003+05:30

There is no doubt that iOS has a very rich set of APIs and that richness is getting just better with each release of the OS. Blocks, ARC, GCD, Background Fetch etc are making the things a lot more easier and thus makes the app more intuitive in terms of performance and in terms of usability.

Since long people/developers have wanted to incorporate the voice interaction into their app and this made devs use other frameworks like OpenEar etc which is quite difficult to implement in real sense.

But, with the introduction of iOS 7, iOS has received a set of APIs to accomplish the text to voice functionality that too in different voices, based on the devices current locale or can be set through code. So, lets dive into it.

AVSpeechSynthesizer is the class under AVFoundation framework which is used to leverage the text to voice functionality. There are a couple of other classes involved as well to handle the things like speed, pitch, voice etc.

The text to voice can be implemented in simple four lines of code as below,

AVSpeechUtterance *utterence = [[AVSpeechUtterance alloc] initWithString:@"Hi there."];

utterence.rate = 0.25f;

AVSpeechSynthesizer *synthesizer = [[AVSpeechSynthesizer alloc] init];

[synthesizer speakUtterance:utterence];

And wollahh!! you are done.

But that is not all.

Notice that we have created an AVSpeechUtterance object. Utterance basically defines the kind of speech you want including pitch, speed, voice, volume, pre and post delays between speeches.

Right now we have just defined an utterance with the speed(.25) we wanted, and we can add above properties to the speech as needed. The speed can vary from 0.0f (super slow) to 2.0f(super fast). Take a look at the class for more on it.

Also, one thing to be noted about AVSpeechSynthesizer is that if there is an ongoing speech and you ask the synthesizer to speak another text, this text will be added in a queue and will be spoken after the first speech is finished. So, in summary only one text/speech can be spoken at a time, rest are added in queue and dequeued on first come first serve (FCFS).

We have just made the Siri say few words in devices current locale voice. Now lets go ahead an change the voice on demand which it can be done as below,

AVSpeechSynthesisVoice *voice = [AVSpeechSynthesisVoice voiceWithLanguage:@"zh-CN"];

[utterence setVoice:voice];

Notice that we have created a voice object and have set the voice to utterance. So, again its the utterance that has all the attributes of a speech. Also, in above, we have set the voice to Chinese but that doesn't mean that out English text will be converted to Chinese and Siri will speak in Chinese :).

It simply means that the voice will be like a English spoken by a Chinese person, in short voice is the accent of speech.

Voice strings can be like en-US (English- United States), ar-SA (Arabic- Saudi Arabia), fr-FR (French - France), zh-CN (Chinese - China) and many more.

AVSpeechSynthesizer does have a set of delegate methods in protocol AVSpeechSynthesizerDelegate, which keeps you posted on the current state of the speech, started, ended, cancelled, the word that will be spoken next etc. However all the delegate methods are optional. Below are the list of delegate methods,

- (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer didStartSpeechUtterance:(AVSpeechUtterance *)utterance;

- (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer didFinishSpeechUtterance:(AVSpeechUtterance *)utterance;

- (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer didPauseSpeechUtterance:(AVSpeechUtterance *)utterance;

- (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer didContinueSpeechUtterance:(AVSpeechUtterance *)utterance;

- (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer didCancelSpeechUtterance:(AVSpeechUtterance *)utterance;

- (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer willSpeakRangeOfSpeechString:(NSRange)characterRange utterance:(AVSpeechUtterance *)utterance;

Checkout the below video to see the AVSpeechSynthesizer in action in a demo app.

(Sorry that the sound is not there, as it is the screen recording, but you can checkout the code an see for yourself)

The source code of this demo app can found at my Github page here.

Thanks for checking it out and happy coding :)

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Display toolbar with keyboard in iOS

2012-09-21T00:45:00.001+05:30

Keyboard is the most basic component that we use to interact with our application, input data to a field.
In most of the cases the buttons available on default keyboard is enough to fulfill the requirement but to make the application more interactive, intuitive we may tend to add some stuffs, controls over keyboard to aid our requirement in an elegant way.

For an example, consider a situation where user needs to input some description in a UITextView on a screen.
One way could be that you use the keyboard return/done tap event to dismiss the keyboard and that may sound okay, but what if user wanted to supply a line break (paragraph) in his description text. In this case, user has no way but to leave it as it is, henceforth leaving a user down.

Other way could be display a pair of buttons, "Cancel" "Apply" , in the top on the navigation bar of screen. This will again work, but from a users perspective, user needs to type some 100 characters on keyboard and move his thumb all the way up to reach those abandoned buttons. Again a no-no from user point of view.

Now, what if we add a toolbar right above the keyboard with those "Cancel", "Apply" button. Yeay!!!
Like this..Sounds good.

How to do it ???

There could be plenty of ways to show a toolbar above keyboard, like adding a custom view on self view, animating the view all the way from bottom to keyboard height with matching keyboard animation speed and again reversing the sequence when keyboard goes away. Annoying.. (Not to mention, I used to the same before coming to know the best solution).

Yes, the solution itself is in the UITextField and UITextView classes in the "inputAccessoryView" property.
It is an accessory view to display when the UITextField or UITextView becomes first responder. and this accessory view is displayed right above the keyboard, as we wanted for our problem.

For example we can create a custom view or a xib with toolbar and required buttons and set the inputAccessoryView as our view. The supplied view will be displayed above the keyboard.

It can be done as below,


UIView *accessoryView=[[[NSBundle mainBundle] loadNibNamed:@"AccessoryView" owner:self options:nil] lastObject];

    _textField.inputAccessoryView=accessoryView;

//    _textField.inputView=accessoryView;    

    accessoryView=nil;

Here, we are loading a custom xib "AccessoryView" and assigning it to the inputAccessoryView of the current responder textField. Thus the AccessoryView will be displayed above the keyboard with "Cancel" and "Apply" buttons.

To add, "inputView" property of UITextField and UITextView classes is the view to be displayed when they become the first responder.
For example, if in above code "inputAccessoryView" is replaced by "inputView", it will show "AccessoryView" only when the textField becomes first responder i.e, keyboard won't be there.

"inputAccessoryView" are useful in more cases like to display auto complete text, display addition characters, smileys etcs while user types. This may look elegant and usable in any way! Like this one,

More info on "inputAccessoryView" and "inputView" can be found here.

You can download an example code and checkout yourself.

Hope this helps.

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Developer Essentials for MacOS Lion and XCode 4.3

2012-05-25T15:45:00.000+05:30

In most of the cases as soon as you are done with the installation of MacOS Lion on your Mac, you may probably find below unexpected and unknown things.

So, here is a list of some unexpected situations that you may face and solution for it.

+ MacHD asks for password if you create or delete any folder MacOS Lion?

Solution: Navigate to "MacHD" > Right click on "MacHD" icon > Select "Get Info" > Scroll down to "Sharing & Permissions" and change the privilege to "Read & Write" for all. It will not ask for permission again.

+ How to Show/Unhide "Library" folder MacOS Lion or XCode 4.3?

Solution: Open Terminal from Utilities in Applications directory and run this command, "chflags nohidden ~/Library/", (without inverted commas).

+ Installed Application location in iPhone Simulator in MacOS Lion or XCode 4.3

Solution: Applications installed on iPhone simulator in XCode 4.3 resides at this location ".//Library/Application Support/iPhone Simulator/5.1/Applications/F8CFC9C3-D21C-4E08-920B-4F09256868F6/YourApplicationName.app". You can list all the applications and see their locations with below command "find ./ -name "YourApplicationName.app"" (without first and last inverted commas), and of course you can navigate directly to the application location using "Go To Folder" option in Finder > Go menu drop down.

Hope this helps!

Facebook wall post parameters

2012-03-02T18:37:00.001+05:30

As you already know, Facebook iPhone app is the most downloaded app on iTunes AppStore and sharing contents on Facebook has become an usual requirement in iPhone apps.

To post a feed on user's wall, we need to provide a set of values in the form of dictionary.

To post a feed, we use below method of facebook class,

[facebook dialog: @"feed"

andParams: params

andDelegate: self];

Here, 'params' is the dictionary that contains set of values to be posted on Facebook users wall.

A typical feed may look like below,

-(void)postToFacebook{

NSString *description = @"Nice app to see movie trailers!";

NSString* propString = @"{\"Download it free: \":{\"href\":\"http://itunes.apple.com/us/app/itunes-movie-trailers/id471966214?mt=8\",\"text\":\"On iTunes AppStore\"}}";

// post FB dialog

NSMutableDictionary *params = [NSMutableDictionary dictionaryWithObjectsAndKeys:

@"iTunes Movie Trailers!", @"name", // Bold/blue name

@"www.apple.com", @"caption", // 1st line

description, @"description", // 2nd line

@"http://itunes.apple.com/us/app/itunes-movie-trailers/id471966214?mt=8", @"link",

@"http://www.blogcdn.com/www.tuaw.com/media/2011/10/imovietrailersapp.jpg", @"picture",

propString, @"properties",

nil];

[facebook dialog: @"feed"

andParams: params

andDelegate: self];

}

Using this, the wall post on web page will look like below,

eg. wall post

Keep integrating Facebook in your application !!!

Custom tab bar in iphone

2012-01-06T14:47:00.000+05:30

Tab bar in iPhone application is a desirable control when your application has multiple section and subsections. It takes viewControllers to create the tabs and display on the view/window. The default color of tab bar controller is black.

With introduction of iOS 5.0, we can change its tint color using,

tabBar.tintColor=[UIColor greenColor];

But, this is not enough to satisfy our taste buds. We are not at all going to create a custom tab bar, any inheritance etcs. We are just going to have some Image layers put onto the tab bar. With a little tweak, we can use whatever image we like in tab bar.

For this we will need a set of Image for every tab like,

Now, we will need to initialize our view controller in "didFinishLaunchingWithOptions" method as below,

FirstViewController *firstViewController=[[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:[NSBundle mainBundle]];

FifthViewController *fifthViewController=[[FifthViewController alloc] initWithNibName:@"FifthViewController" bundle:[NSBundle mainBundle]];

and add to tab bar controller,

NSArray *arr=[NSArray arrayWithObjects:firstViewController,secondViewController,thirdViewController,fourthViewController,fifthViewController,nil];

tabBarController=[[UITabBarController alloc] init];

[tabBarController setViewControllers:arr];

Finally add this tab bar controller to the window,

[self.window addSubview:tabBarController.view];

Complete "didFinishLaunchingWithOptions" method in AppDelegate.m of application will typically look like below,

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{

// Override point for customization after application launch.

FirstViewController *firstViewController=[[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:[NSBundle mainBundle]];

SecondViewController *secondViewController=[[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:[NSBundle mainBundle]];

ThirdViewController *thirdViewController=[[ThirdViewController alloc] initWithNibName:@"ThirdViewController" bundle:[NSBundle mainBundle]];

FourthViewController *fourthViewController=[[FourthViewController alloc] initWithNibName:@"FourthViewController" bundle:[NSBundle mainBundle]];

FifthViewController *fifthViewController=[[FifthViewController alloc] initWithNibName:@"FifthViewController" bundle:[NSBundle mainBundle]];

NSArray *arr=[NSArray arrayWithObjects:firstViewController,secondViewController,thirdViewController,fourthViewController,fifthViewController,nil];

tabBarController=[[UITabBarController alloc] init];

[tabBarController setViewControllers:arr];

[self.window addSubview:tabBarController.view];

[self.window makeKeyAndVisible];

return YES;

}

Now, the idea is that, we can add an ImageView over the tab bar and update the image with tab change in viewWillAppear method of every viewController as below,

- (void)viewWillAppear:(BOOL)animated {

[super viewWillAppear:animated];

for(UIView *view in self.tabBarController.tabBar.subviews) {

if([view isKindOfClass:[UIImageView class]]) {

[view removeFromSuperview];

}

[self.tabBarController.tabBar insertSubview:[[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"1.png"]] autorelease] atIndex:1];

}

You can download the example code from here.

Weak link in iphone SDK

2011-09-28T09:29:00.000+05:30

Well, there happened a case when I was using the latest iOS SDK for the development purpose, and built an application which utilized the eventKit framework, and the framework used "eventKit" was a new addition to the framework list.

I used the eventKit on the fly and submitted to the appstore for the approval process, and as a matter the application was approved.

But, the case happened when the application was being downloaded and it used to crash at the app launch on the earlier iOS's.

Digging around the problem, I came to know about the weak link thing for a framework, and uploaded the updated build to app store.

The idea is that, If you are using a framework that is not available to all the devices that you have selected as target devices, make the framework as weak link.

This can be done as below:
* Select the project target > Right click > Get-Info.
* Go to general tab > Linked libraries.
* Select the framework and make it a weak link.

Also, keep in if you mark a framework as weak linked, be sure to check for its availability before using any of its functionally.

You can check for the existence of the class like below code sample:

Class theClass = (NSClassFromString(@"UILocalNotification"));
if(theClass){
// Class exists
}
else{
// Class does not exists
}

List of Android emulator shortcuts

2011-09-24T12:29:00.000+05:30

Android development is like cream, handling the emulator is on the other side.
Android emulator almost covers up the screen. In some cases you may not even see the
'Home' button of the emulator screen, like on screens with resolution 1366 x 768.
Using android emulator shortcuts is the best way to get rid of such problems. Using shortcuts may
also increase the speed at which you work with the emulators.
Thus regardless of the screen resolution use of android emulator shortcuts is always encouraged.

Here is a list of android emulator shortcut keys:

Escape Back button
Home Home button
F2 PageUp Menu button
Shift-F2   PageDown Start button
F3   Call/Dial button
F4   Hangup/EndCall button
F5   Search button
F7   Power button
Ctrl-F3 Ctrl-KEYPAD_5 Camera button
Ctrl-F5 KEYPAD_PLUS Volume up button
Ctrl-F6 KEYPAD_MINUS Volume down button
KEYPAD_5 DPAD center
KEYPAD_4 DPAD left
KEYPAD_6 DPAD right

KEYPAD_8    DPAD up
KEYPAD_2 DPAD down
F8   Toggle cell network on/off
F9   Toggle code profiling (when -trace set)
Alt-ENTER Toggle fullscreen mode
Ctrl-T Toggle trackball mode
Ctrl-F11, KEYPAD_7 Rotate screen orientation to previous or next layout
Ctrl-F12, KEYPAD_9 Rotate screen orientation to previous or next layout

And now, Start using the shortcuts...

Change apple push notification view button text

2011-08-11T13:17:00.000+05:30

We can not change the text of cancel button, but the view button text can be changed.

The payload dictionary has a field "action-loc-key", which takes the alternate text for view button.

The payload dictionary can look like,

{

"aps": {

"alert": {

"body": "Bob wants to play poker",

"action-loc-key": "PLAY"

"badge": 5,

"acme1": "bar",

"acme2": [

"bang",

"whiz"

]

}

Here the text "Bob wants to play poker" will be the body of alert. and there will "cancel" and "PLAY". Here button text view will be replaced by "PLAY".

For more details on this visit apple reference document here.

method list in alphabetical order in xcode 4

2011-08-10T14:07:00.000+05:30

There was an option in Xcode-3x in preference with a check box to enable or disable the alphabetical listing of methods, as seen in below picture:

(Xcode3.x option)

In Xcode-4x they have removed this option.

To list the methods alphabetically press ⌘ and click on the level in the path menu, as in below picture:

(Xcode4.x, ⌘+click)

Personally I liked the new feature in Xcode4, as we can list the methods alphabetically or sequentially whenever we want unlike Xcode3 where we had to stick with the option selected in settings tab.

Displaying map in Facebook feed in iOS

2011-08-09T20:07:00.000+05:30

Sharing images on Facebook feeds is desirable most of the times and can be accomplished by using the attachments in the params dictionary.

I went on a problem to post a Facebook feed that shares users current location as static map image.

The options available was to use a static image from google and use the url as value for 'picture' key in feeds parameters.

But, doing this didn't work. It didn't showed any image on the wall.

If you have a server that can cache and provide you the direct url of the static map image (generated by Microsoft Bing Map or Google Map), you can use that url for the feed purpose.

But, since I didn't had any, I had no option but to see for workarounds.

Searching for the solutions, certainly I found that Foursquare application does share the users location in feed. This foursquare proxy server url returns the static image of size 100x100 from Microsoft Bing Map. You can change the lat/long value in the url and get the desired map for your location.

It uses its proxy servers to generate and handle the map images.

The url for image is of below format,

https://foursquare.com/mapproxy/18.5163333/73.9299163/map.png

Its implementation code can look like below,

NSMutableDictionary* params = [NSMutableDictionary dictionaryWithObjectsAndKeys:

kFacebookAppId, @"app_id",

@"http://developers.facebook.com/docs/reference/dialogs/", @"link",

@"https://foursquare.com/mapproxy/18.5163333/73.9299163/map.png", @"picture",

@"Facebook Dialogs", @"name",

@"Reference Documentation", @"caption",

@"Dialogs provide a simple, consistent interface for apps to interact with users.", @"description",

@"Facebook Dialogs are so easy!", @"message",

nil];

[facebook dialog:@"feed" andParams:params andDelegate:self];

Thanks and hope this helps.

How to disable Facebook Single Sign On (SSO)

2011-08-02T18:00:00.000+05:30

Single Sign On is the desirable feature in almost all applications supporting Facebook.

However, if you tend to a scenario where you do not want this SSO feature, you can

omit the feature in a simple single step without removing any of your code during

implementation of SSO.

To get away from SSO open Facebook.m file and replace method

- (void)authorize:(NSArray *)permissions

delegate:(id<FBSessionDelegate>)delegate {

[_permissions release];

_permissions = [permissions retain];

_sessionDelegate = delegate;

[self authorizeWithFBAppAuth:YES safariAuth:YES];

}

with

- (void)authorize:(NSArray *)permissions

delegate:(id<FBSessionDelegate>)delegate {

[_permissions release];

_permissions = [permissions retain];

_sessionDelegate = delegate;

[self authorizeWithFBAppAuth:NO safariAuth:NO];

}

In SSO implementation the method "authorizeWithFBAppAuth" takes parameter as "YES", which indicates Facebook to whether authorize from native Facebook application or from native Safari application.

Supplying the parameter as "NO" signifies not to open any other application for user authentication. And the application shows its authentication dialogue within application.

Thats all you need to do, and the Facebook authentication dialogue opens within your application.

Difference between Copy and MutableCopy

2011-07-26T20:38:00.000+05:30

The difference between 'copy' and 'mutableCopy' can be simply understood with polymorphism in Object Oriented Programming concepts.

We will take the example of Array in objective-C. MutableArray is the extension of NSArray class. Therefore, all the methods available in NSArray is available in NSMutableArray, but the additional methods present in NSMutableArray is not known to NSArray class.

Now moving ahead, the copy method on an NSArray will return an object of type NSArray(The array that can not be modified). And mutableCopy method will return an object of mutable type (The array that can be modified).

Now, there can below cases :

Case 1:

NSArray *arr1=[NSArray arrayWithObjects:@"A",@"B",@"C", nil];

NSArray *arr2=[arr1 copy];

NSLog(@"arr1:%@",[arr1 description]);

NSLog(@"arr2:%@",[arr2 description]);

In this case an NSArray object is returned and is received in an NSArray object.

So, the array received can not be modified.

Therefore, we will not be able to use below statement

[arr2 insertObject:@"Z" atIndex:0];

Case 2:

NSArray *arr1=[NSArray arrayWithObjects:@"A",@"B",@"C", nil];

NSArray *arr2=[arr1 mutableCopy];

NSLog(@"arr1:%@",[arr1 description]);

NSLog(@"arr2:%@",[arr2 description]);

In this case an NSMutableArray object is returned and is received in an NSArray object.

Since the receiver object is of type NSArray, it doesn't know the methods present in NSMutableArray, arr2 will not be able to use any of the methods of NSMutableArray.

That is, the method mutableArray will make no sense in this scenario.

So, we will not be able to use below statement

[arr2 insertObject:@"Z" atIndex:0];

Case 3:

NSArray *arr1=[NSArray arrayWithObjects:@"A",@"B",@"C", nil];

NSMutableArray *arr2=[arr1 copy];

NSLog(@"arr1:%@",[arr1 description]);

NSLog(@"arr2:%@",[arr2 description]);

In this case an NSArray object is returned and is received in an NSMutableArray type object. The receiver arr2 is now pointing to an object address that is of type NSArray. However arr2 has the additional methods than NSArray, it will not be able to use those methods coz the pointed object NSArray does not know the additional methods present in arr2(NSMutableArray).

Hence, we will not be able to use below statement

[arr2 insertObject:@"Z" atIndex:0];

Case 4:

NSArray *arr1=[NSArray arrayWithObjects:@"A",@"B",@"C", nil];

NSMutableArray *arr2=[arr1 mutableCopy];

NSLog(@"arr1:%@",[arr1 description]);

NSLog(@"arr2:%@",[arr2 description]);

[arr2 insertObject:@"Z" atIndex:0];

In this scenario, the receiver(arr2) of type NSMutableArray receives an object of type NSMutableArray. Therefore, the receiver knows the additional methods of NSMutableArray as well as the object that is being pointed by receiver(arr2).

And finally below statement will work like charm,

[arr2 insertObject:@"Z" atIndex:0];

Log before insertion will be:

arr1:(

)

arr2:(

)

And log after insertion will be:

arr1:(

)

arr2:(

)

Hope above description helped you.

Random questions in iOS

2011-07-23T16:17:00.000+05:30

1) How to disable UIWebView scrolling ?

Ans: UIWebView is derived from UIScrollView. Therefor we must be able to disable the scrolling of UIWebView.

Here is the working code:

UIScrollView *scrollView=[[webView subViews] lastObject];

[scrollView setScrollingEnabled: NO];

2) How to check the iOS version of device ?

Ans: This is a very frequent scenario where you need to check which version of iOS the target device is running.

The very best solution that Apple recommends is,

if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1) {
// Load resources for iOS 6.1 or earlier
} else {
// Load resources for iOS 7 or later
}

Blank status bar problem with MediaPlayer

2011-07-12T18:03:00.000+05:30

Playing videos in iOS is like butter and nothing much on developer side.

iOS has provided MediaPlayer.framework to play videos either from resource or from a http url.

In a full screen application development, you might come across the problem that, after finish of the video play the status bar is hidden and the place for status bar is left blank (white).

Also, this problem may occur when you present the MoviePlayerViewController on current view and not on adding MoviePlayerViewController's view on the parent view
i.e,

[self presentMoviePlayerViewControllerAnimated:moviePlayerViewController];

not on doing

[self.view addSubview:[[moviePlayerViewController moviePlayer] view]];

Hey, and do not forget to test your code on iPad device, as you can find this problem only on device & works fine on simulator.

You will notice that the status bar is left blank when you click on "Done" button while video is being played. If the video ends after full video play everything goes right.

This white status bar may look like this:

To handle this problem, We add observers for MPMoviePlayer class notifications and all you need is to set the status bar hidden in the method implementation of 'MPMoviePlayerPlaybackDidFinishNotification' notification, as below:

We can add MoviePlayer notification observers as below:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(_MPMoviePlayerPlaybackDidFinishNotification) name:MPMoviePlayerPlaybackDidFinishNotification object:nil];

The implementation for 'MPMoviePlayerPlaybackDidFinishNotification' can be as below:

-(void)_MPMoviePlayerPlaybackDidFinishNotification{

[[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationSlide];

}

That is all we need to do.

You can download the working code here

Horizontal scroll using tableView

2011-06-27T17:46:00.000+05:30

Very recently I happened to be in an efficiency problem with displaying large amount of images.

The problem was that I had to display more than 1000s images in horizontal in a way that user can scroll through in an easy and efficient way.

In this case the very first thing that may come in to mind is using a ScrollView with ImageViews added into them. In such a case we have to do a lot of book keepings and I didn't wanted that.

Certainly an idea came into my mind, why not to using TableView with the help of QuartzCore… as below.

Using QuartzCore we can rotate/transform the view. So, I added the table view on my view and rotated it by -90 degree (i.e, anti-clockwise) and made some adjustment in the view frame. Now, the table view is in horizontal mode.

Only thing is that image in cell is still not proper. So, change rotate the imageView also by +90 degree (i.e, clockwise). Hurrahhh!!! task complete..

Initially the screen looked like this,

Vertical table view

Final screen would look like this.

Horizontal table view

Rotating the tableView:

m_tableView.layer.transform = CATransform3DRotate(CATransform3DIdentity,-1.57079633,0,0,1);

m_tableView.frame=CGRectMake(0,200, 700,234);

Rotating the imageView:

imageView.layer.transform = CATransform3DRotate(CATransform3DIdentity,1.57079633,0,0,1);

imageView.frame=CGRectMake(0,0,234,150);

Be sure to implement the lazy loading… for a better user experience.

Updated:
Finally got some time to create a sample for the stated purpose. The example will look like below.

Custom Gallery

Here is the sample code that may help you go ahead. Be sure to run in Landscape mode... I am sorry that I didn't check for memory in this short time. Please make changes while using...

release Vs drain in autorelease pool

2011-03-23T14:57:00.000+05:30

An autorelease pool stores objects that are sent a release or autorelease message and are deallocated when the autorelease pool itself is drained.

If a question like "what to use? 'drain' or 'release' ? comes in your mind, below is the simple resolve for your question.

release:

In a reference-counted environment, since an autorelease pool cannot be retained , this method causes the receiver to be deallocated. When an autorelease pool is deallocated, it sends a 'release' message to all its autoreleased objects. Also, In a garbage-collected environment, this method is a no no.

- (void)release

drain:

In a reference-counted environment, releases and pops the receiver; in a garbage-collected environment, triggers garbage collection if the memory allocated since the last collection is greater than the current threshold.

- (void)drain

Conclusion:

From the above brief discussion it is clear that, we should always use 'drain' over 'release' for an autorelease pool(be the Cocoa or Cocoa touch).

Determine if string is numeric only

2011-03-16T21:04:00.000+05:30

In Objective-C there is no in-built method which determines whether the given string is numeric only or is an alphanumeric, but has provided ways to do that.

The objective can be achieved using the NSCharacterSet class, which provides a set of characters.
Using below method we can identify the whether the string is numeric or alphanumeric.

- (void)testNumeric{
   NSString *result=@"2011";
   if([self isNumeric:result]){
// Numeric
   }else{
// Alphanumeric
   }
}
- (BOOL)isNumeric:(NSString*)inputString{
   BOOL isValid=NO;
   NSCharacterSet *alphaNumbersSet = [NSCharacterSet decimalDigitCharacterSet];
   NSCharacterSet *stringSet = [NSCharacterSet characterSetWithCharactersInString:inputString];
   isValid = [alphaNumbersSet isSupersetOfSet:stringSet];
   return isValid;
}

decimalDigitCharacterSet is a character set containing the characters in the category of Decimal Numbers,i.e, the set with all numeric characters.

Method characterSetWithCharactersInString: returns the character set containing the characters in the given string, i.e, the set with characters '2','0','1','1' in our case.

Using the two sets, we determine whether all characters of inputString is contained in alphaNumbersSet.

Happy coding.

Auto Play youtube video in iPhone / iPad

2011-03-02T12:05:00.000+05:30

Playing a youtube video in iOS sdk can be done in two ways:
1) Invoke the native youtube player in the device.
2) Open the youtube video link in a WebView.
3) Autoplay the youtube video using WebView .

Method 1:
This method utilizes the Apple's URLScheme to play youtube video by launching the youtube application on the device. This involves a simple call to the openURL method of UIApplication class as below:

NSURL *url=[NSURL URLWithString:@"http://www.youtube.com/v/IkvXcvb7rkg?f=user_favorites&app=youtube_gdata\"];
[[UIApplication sharedApplication] openURL:url];

This method may seem easy, but it's at the cost that the video will be played in other application
and your application will not be called even after the video playing is finished.
There is no other way to return to your application after video playing is done.

Method 2:
This method involved a little bit of tweak around the UIWebView control.
In this method a youtube embed code is constructed and is loaded in the WebView control in the application.
The WebView displays the video thumbnail and a play button over the thumbnail. As the user taps on the play
button the video is launched in QuickTime player and after the video playing is done, control is returned to the application.

                                                           (YouTube video in WebView with play button )

So, with a little bit of tweak we can retain the control in the application.

    NSString *htmlString =@"<html><head>"
        "<meta name = \"viewport\" content = \"initial-scale = 1.0, user-scalable = no, width = 212\"/></head>"
        "<body style=\"background:#FFFFF;margin-top:20px;margin-left:0px\">"
        "<div><object width=\"320\" height=\"240\">"
        "<param name=\"wmode\" value=\"transparent\"></param>"
        "<embed src=\"http://www.youtube.com/v/Hu684V2lB3Q?f=user_favorites&app=youtube_gdata\""
        "type=\"application/x-shockwave-flash\" wmode=\"transparent\" width=\"320\" height=\"240\"></embed>"
        "</object></div></body></html>";

    [webView loadHTMLString:htmlString baseURL:nil];

Method 3:
This method takes takes the 'Method 2' one step ahead by utilizing the delegate methods of WebView control
to auto play the video in QuickTime player as soon as the WebView loading is finished.

(Playing video in QuickTime player)

You need to assign the class as WebView delegate:

webView.delegate=self;

The idea is to find the play button on the WebView and send the button touch event to the control to play the video.

Complete code will look like this:

    NSString *htmlString =@"<html><head>"
        "<meta name = \"viewport\" content = \"initial-scale = 1.0, user-scalable = no, width = 212\"/></head>"
        "<body style=\"background:#FFFFF;margin-top:20px;margin-left:0px\">"
        "<div><object width=\"320\" height=\"240\">"
        "<param name=\"wmode\" value=\"transparent\"></param>"
        "<embed src=\"http://www.youtube.com/v/Hu684V2lB3Q?f=user_favorites&app=youtube_gdata\""
        "type=\"application/x-shockwave-flash\" wmode=\"transparent\" width=\"320\" height=\"240\"></embed>"
        "</object></div></body></html>";

    webView.delegate=self;
    [webView loadHTMLString:htmlString baseURL:nil];

- (void)webViewDidFinishLoad:(UIWebView *)_webView {
    UIButton *b = [self findButtonInView:_webView];
    [b sendActionsForControlEvents:UIControlEventTouchUpInside];
}

- (UIButton *)findButtonInView:(UIView *)view {
    UIButton *button = nil;

    if ([view isMemberOfClass:[UIButton class]]) {
        return (UIButton *)view;
    }

    if (view.subviews && [view.subviews count] > 0) {
        for (UIView *subview in view.subviews) {
            button = [self findButtonInView:subview];
            if (button) return button;
        }
    }
    return button;
}

I prefer Method 3 over all the methods but you choose the one that suits your need.

Happy coding...

iPad Launch screen image

2011-02-23T19:10:00.000+05:30

With the usual requirement every iPad application is supposed to support all the orientations available, which a nice to have feature. In general the applications using a launch image for splash screen.

To supply an launch image, we use an image named as Default.png and is added to the resource folder of the application, and this image is loaded as launch image when the application is launched.

Since, we are using a single image for all orientations, there may be a case where the splash image me look stretched, blur, crisped (depending upon the image used).

This happens due to the different screen size of the device at different orientations. Landscape: 1024w x 748h and Portrait: 768w x 1004h.

To get this thing to work we can create images with names and dimensions as mentioned below, and add them to the application resource folder (no code required).

Default-Portrait.png    768w x 1004h
Default-PortraitUpsideDown.png    768w x 1004h
Default-Landscape.png    1024w x 748h
Default-LandscapeLeft.png    1024w x 748h
Default-LandscapeRight.png    1024w x 748h
Default-PortraitUpsideDown.png    1024w x 748h

Clean the project by pressing Command+shift+k or from Build>Clean.
All set to go now, run the application.

NSSearchField return, arrow key press notification

2011-02-23T11:56:00.000+05:30

In Cocoa development environment you might find NSSearchField difficult to trap the enter key event.
Also it becomes difficult to get the arrow key movements events.

In order to get these things to work, you need to do some simple stuffs with IBOutlet. You just need to connect your controller class with the delegate of NSSearchField.

In the controller class use below code to get the job done:

-(BOOL)control:(NSControl*)control textView:(NSTextView*)textView doCommandBySelector:(SEL)commandSelector {
    NSLog(@"doCommandBySelector");
    BOOL result = NO;
    if (commandSelector == @selector(insertNewline:)) {
        // enter key pressed
        result = YES;
    }
    else if(commandSelector == @selector(moveLeft:)) {
        // left arrow key pressed
        [textView moveLeft:nil];
        result = YES;
    }
    else if(commandSelector == @selector(moveRight:)) {
        // right arrow key pressed
        [textView moveRight:nil];
        result = YES;
    }
    else if(commandSelector == @selector(moveUp:)) {
        // up arrow key pressed
        result = YES;
    }
    else if(commandSelector == @selector(moveDown:)) {
        // down arrow key pressed
        result = YES;
    }
    return result;
}

Also, If you are interested in only in enter key event, set your controller class as the delegate of NSSearchField and implement the below method, which will be called when enter key is hit on the NSSearchField:
- (void)controlTextDidEndEditing:(NSNotification *)obj{
    NSLog(@"Enter key is hit");
}

* How to get the text out of NSSearchField:
The notification object(obj) in controlTextDidEndEditing method has the userInfo dictionary which contains the reference to the NSTextField in the NSSearchField control. Use below code to get the NSTextField object and the text in it.
NSTextView* textView = [[obj userInfo] objectForKey:@"NSFieldEditor"];
NSString *searchText=[textView string];

Let me know if something can be improved.

Foursquare

2011-02-21T20:27:00.000+05:30

Where to register your application:
https://foursquare.com/oauth/

Working with UILocalNotification in iOS

2011-02-20T17:01:00.000+05:30

Back was the time before iPhone OS 3.0, APNS (apple push notification) was introduced. APN's are the means to send a remote notifications to a device connected to the internet.

With the increasing need of scheduling reminders at the device level, Local notification was introduced with the release iOS 4.0 . With the help of local notification, we can schedule a notification for any required date-time and the notification is handled by the device itself, no need to be connected to the
internet or a remote server.

UILocalNotification is the class behind the local notifications and the customization of the notification.

Local notification limitation:
Every application is allowed a maximum of 64 local notifications. iOS takes the upcoming 64 scheduled notifications and notifies for these notifications only, rest notifications are ignored.

1) How to registering Local notification:

    // Check for whether device supports local notification
    Class cls = NSClassFromString(@"UILocalNotification");
    if (cls != nil) {

        UILocalNotification *notif = [[cls alloc] init];
        notif.fireDate = [datePicker date];
        notif.timeZone = [NSTimeZone defaultTimeZone];

        notif.alertBody = @"Whooaa?";
        notif.alertAction = @"Show";    // alert button title (other than cancel)
        notif.soundName = UILocalNotificationDefaultSoundName; (default alert sound name, can be cutomized)
        notif.applicationIconBadgeNumber = 1;

        // Associate a dictionary to identify to gather the information about the notification
        NSDictionary *userDict = [NSDictionary dictionaryWithObject:@"Notification text"
                                                forKey:kRemindMeNotificationDataKey];
        notif.userInfo = userDict;

        [[UIApplication sharedApplication] scheduleLocalNotification:notif];
        [notif release];
    }

This will create a notification with the date selected in "datePicker" control.

In this case application name will be the title and "Whoaaa?" will be the body of the alert message, "Show" will be the title of the action button on alert (other than cancel button).

userInfo is the dictionary you will receive in the delegate method of the local notification. So, you can add your desired information for the notification to the dictionary while creating a notification.

2) How to handle notification delegate:

- This delegate method will be called If user tapped "Show Me" button and the application was running in background or was in active state.

- (void)application:(UIApplication *)application
        didReceiveLocalNotification:(UILocalNotification *)notification {

    application.applicationIconBadgeNumber = 0;
    NSString *reminderText = [notification.userInfo
                            objectForKey:kRemindMeNotificationDataKey];

    // Call to a method to handover the notification handling
    [viewController handleReminder:reminderText];
}

- This delegate method will be called If user tapped "Show Me" button and the application was not running in background.

- (BOOL)application:(UIApplication *)application
    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    Class cls = NSClassFromString(@"UILocalNotification");
    if (cls) {
        UILocalNotification *notification = [launchOptions objectForKey:
                                UIApplicationLaunchOptionsLocalNotificationKey];

        if (notification) {
            NSString *reminderText = [notification.userInfo
                                    objectForKey:kRemindMeNotificationDataKey];

            // Call to a method to handover the notification handling
            [viewController handleReminder:reminderText];
        }
    }

    application.applicationIconBadgeNumber = 0;

    [window addSubview:viewController.view];
    [window makeKeyAndVisible];

    return YES;
}

3) How to cancel all local notification:
You can cancel the selected local notification if you have preserved the notification object like,

[[UIApplication sharedApplication] cancelLocalNotifications:notif];

where "notif" is the notification object(saved/unsaved) .

and you can cancel all the local notifications by calling below,
[[UIApplication sharedApplication] cancelAllLocalNotifications];

4) Custom alert sound:
To make your local notification make a custom sound, you will have to provide the name of the sound file with extension as .caf . This sound file must be in your application resource bundle.
Below code registers a custom notification sound called "alert.caf".
notif.soundName = @"alert.caf";

Note: Alert sound must have .caf extension.

Emptying the trash using terminal

2011-02-09T11:34:00.000+05:30

In Mac OSx, trashing a file takes it to the .Trash folder of the logged in user (unless we have used the option+delete command). If the trash folder is over whelmed with files in it, emptying the trash may not work, or delete all the files and folders in it.

In such case we have have the tool "Terminal" to empty the trash using unix command.

Mac OSx has unix in its kernel and thus gives the freedom to use the unix commands to perform our task.

How to delete the file in Trash:

.Trash is the folder in every user account at location /Username/.Trash.

Open terminal from /Application/Utilities/ folder, enter the command "cd .Trash" in terminal and hit enter. Now you are in the .Trash directory.

Use -rm command to delete the file or folder.

If you want to empty the trash: $ rm -rf *.*

and If want to delete specific file: rm -rf filename_with_extension

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

For more help about any unix COMMAND, use:

$whatis COMMAND

$man COMMAND (- Press RETURN for more, or q when done)

$info COMMAND

SOME MORE UNIX COMMANDS:

------------------------------------------------------------------------------

INTERACTIVE FEATURES

TAB Command completion !!! USEFUL !!!

UPARROW Command history !!! USEFUL !!!

CTRL-C Interrupt current process.

CTRL-D If a program/command waits for input, end input.

------------------------------------------------------------------------------

WILDCARDS AND DIRECTORIES USED IN COMMANDS

* Replaces any string of characters in a file name

except the initial dot.

? Replaces any single character in a file name

except the initial dot.

~ The home directory of the current user.

~abcde123 The home directory of the user abcde123.

.. The parent directory.

. The present directory.

/ The root directory

Example:

ls ~/csc219/*.txt

------------------------------------------------------------------------------

REDIRECTIONS AND PIPES

COMMAND < FILE COMMAND will take input from FILE.

COMMAND > FILE Put output of COMMAND to FILE

COMMAND >> FILE Append the output of COMMAND to FILE

COMMAND 2> FILE Put error messages of COMMAND to FILE.

COMMAND 2>> FILE Append error messages of COMMAND to FILE.

COMMAND > FILE1 2> FILE2 Put output and error messages in separate files.

COMMAND >& FILE Put output and error messages in the same FILE.

COMMAND >>& FILE Append output and error messages of COMMAND to FILE.

COMMAND1 | COMMAND2 Output of COMMAND1 becomes input for COMMAND2.

COMMAND | more See the output of COMMAND page by page.

COMMAND | sort | more See the output lines of COMMAND sorted and page by page.

------------------------------------------------------------------------------

ONLINE HELP

h *Custom help.

COMMAND --help | more Basic help on a Unix COMMAND (for most commands).

COMMAND -h | more Basic help on a Unix COMMAND (for some commands).

whatis COMMAND One-line information on COMMAND.

man COMMAND Display the UNIX manual page on COMMAND.

info COMMAND Info help on COMMAND.

xman Browser for Unix manual pages (under X-windows).

apropos KEYWORD | more Find man pages relevant to COMMAND.

help COMMAND Help on a bash built-in COMMAND.

perldoc Perl documentation.

------------------------------------------------------------------------------

FILES AND DIRECTORIES

ls List contents of current directory.

ls -l List contents of current directory in a long form.

ls -a Same as ls but .* files are displayed as well.

ls -al Combination of ls -a and ls -l

ls DIRECTORY List contents of DIRECTORY (specified by a path).

ls SUBDIRECTORY List contents of SUBDIRECTORY.

ls FILE(S) Check whether FILE exists (or what FILES exist).

pwd Display absolute path to present working directory.

mkdir DIRECTORY Create DIRECTORY (i.e. a folder)

cd Change to your home directory.

cd .. Change to the parent directory.

cd SUBDIRECTORY Change to SUBDIRECTORY.

cd DIRECTORY Change to DIRECTORY (specified by a path).

cd. ARGUMENTS *Same as cd followed by ls

cp FILE NEWFILE Copy FILE to NEWFILE.

cp -r DIR NEWDIR Copy DIR and all its contents to NEWDIR.

cp. ARGUMENTS *Same as cp -r but preserving file attributes.

mv FILE NAME Rename FILE to new NAME.

mv DIR NAME Rename directory DIR to new NAME.

mv FILE DIR Move FILE into existing directory DIR.

ln -s FILE LINK Create symbolic LINK (i.e. shortcut) to existing FILE.

quota Displays your disk quota.

quota. *Displays your disk quota and current disk usage.

rm FILE(S) Remove FILE(S).

rmdir DIRECTORY Remove empty DIRECTORY.

rm -r DIRECTORY Remove DIRECTORY and its entire contents.

rm -rf DIRECTORY Same as rm -r but without asking for confirmations.

clean *Remove non-essential files, interactively

clean -f *Remove non-essential files, without interaction.

junk FILE *Move FILE to ~/junk instead of removing it.

find. FILE(S) *Search current dir and its subdirs for FILE(S).

touch FILE Update modification date/time of FILE.

file FILE Find out the type of FILE.

gzip Compress or expand files.

zip Compress or expand files.

compress Compress or expand files.

tar Archive a directory into a file, or expand such a file.

targz DIRECTORY *Pack DIRECTORY into archive file *.tgz

untargz ARCHIVE.tgz *Unpack *.tgz archive into a directory.

------------------------------------------------------------------------------

TEXT FILES

more FILE Display contents of FILE, page by page.

less FILE Display contents of FILE, page by page.

cat FILE Display a file. (For very short files.)

head FILE Display first lines of FILE.

tail FILE Display last lines of FILE.

pico FILE Edit FILE using a user-friendly editor.

nano FILE Edit FILE using a user-friendly editor.

kwrite FILE Edit FILE using a user-friendly editor under X windows.

gedit FILE Edit FILE using a user-friendly editor under X windows.

emacs FILE Edit FILE using a powerful editor.

vim FILE Edit FILE using a powerful editor with cryptic syntax.

aspell -c FILE Check spelling in text-file FILE.

ispell FILE *Check spelling in text-file FILE.

cat FILE1 FILE2 > NEW Append FILE1 and FILE2 creating new file NEW.

cat FILE1 >> FILE2 Append FILE1 at the end of FILE2.

sort FILE > NEWFILE Sort lines of FILE alphabetically and put them in NEWFILE.

grep STRING FILE(S) Display lines of FILE(S) which contain STRING.

grep. STRING FILE(S) *Similar as above, but better.

wc FILE(S) Count characters, words and lines in FILE(S).

diff FILE1 FILE2 | more Show differences between two versions of a file.

filter FILE NEWFILE *Filter out strange characters from FILE.

COMMAND | cut -b 1-9,15 Remove sections from each line.

COMMAND | uniq Omit repeated lines.

------------------------------------------------------------------------------

PRINTING

lpr FILE In Hawk153B, print FILE from a workstation.

lprint1 FILE *Print text-file on local printer; see help printing

lprint2 FILE *Print text-file on local printer; see help printing

------------------------------------------------------------------------------

PROGRAMMING LANGUAGES

javac CLASSNAME.java Compile a Java program.

java CLASSNAME Run a Java program.

javadoc CLASSNAME.java Create an html documentation file for CLASSNAME.

appletviewer CLASSNAME Run an applet.

lisp *Listener of LISP programming language.

prolog *Listener of Prolog programming language.

python Listener of Python programming language.

cc -g -Wall -o FILE FILE.c Compile C source FILE.c into executable FILE.

gcc -g -Wall -o FILE FILE.c Compile C source FILE.c into executable FILE.

c++ -g -Wall -o FIL FIL.cxx Compile C++ source FIL.cxx into executable FIL.

g++ -g -Wall -o FIL FIL.cxx Compile C++ source FIL.cxx into executable FIL.

gdb EXECUTABLE Start debugging a C/C++ program.

make FILE Compile and link C/C++ files specified in makefile

m *Same as make but directs messages to a log file.

c-work *Repeatedly edit-compile-run a C program.

------------------------------------------------------------------------------

INTERNET

lynx Web browser (for text-based terminals).

firefox Web browser.

konqueror Web browser.

BROWSER Browse the Internet.

BROWSER FILE.html Display a local html file.

BROWSER FILE.pdf Display a local pdf file.

mutt Text-based e-mail manager.

pine Text-based e-mail manager (on some systems).

ssh HOST Open interactive session on HOST using secure shell.

sftp HOST Open sftp (secure file transfer) connection to HOST.

rsync ARGUMENTS Synchronize directories on local and remote host.

------------------------------------------------------------------------------

PROCESS CONTROL

Notes: A process is a run of a program;

One program can be used to create many concurrent processes.

A job may consist of several processes with pipes and redirections.

Processes are managed by the kernel.

Jobs are managed by a shell.

CTRL-Z Suspend current foreground process.

fg Bring job suspended by CTRL-Z to the foreground.

bg JOB Restart suspended JOb in the background.

ps List processes.

ps. *List processes.

jobs List current jobs (A job may involve many processes).

kill PROCESS Kill PROCESS (however some processes may resist).

ctrl-C Kill the foreground process (but it may resist).

kill -9 PROCESS Kill PROCESS (no process can resist.)

kill. PROCESS *Kill PROCESS; same as kill -9.

COMMAND & Run COMMAND in the background.

------------------------------------------------------------------------------

ENVIRONMENT VARIABLES IN BASH

env | sort | more List all the environment variables with values.

echo $VARIABLE List the value of VARIABLE.

unset VARIABLE Remove VARIABLE.

export VARIABLE=VALUE Create environment variable VARIABLE and set to VALUE.

------------------------------------------------------------------------------

MISCELLANEOUS

exit Exit from any shell.

logout Exit from the login shell and terminate session.

svn Version control system.

xterm A shell window under X-windows.

xcalc A calculator under X-windows.

xclock A clock under X windows.

xeyes They watch you work and report to the Boss :-)

date Display date and time.

clear Clear shell window.

xrefresh Refresh X-windows.

reset *Reset session.

setup-account *Set up or reset your account (Mr. Dela's customizations)

------------------------------------------------------------------------------

COURSEWORK IN DR. PLAZA'S COURSES

Commands and directory names related to csc219 have 219 as a suffix.

By changing the suffix you will obtain commands for other courses.

ls $csc219 *List files related to csc219.

cd $csc219 *change into instructor's public directory for csc219.

cp $csc219/FILE . *Copy FILE related to csc219 to the current directory

cp -r $csc219/SUBDIR . *Copy SUBDIR of csc219 to the current directory.

submit *Submit a directory with files for an assignment.

grades *See your grades. Used in some courses only.

------------------------------------------------------------------------------

Weak link in iOS framework

2011-02-07T16:47:00.000+05:30

I used the eventKit on the fly and submitted to the appstore for the approval process, and as a matter the application was approved.

But, the case happened when the application was being downloaded and it used to crash at the app launch on the earlier iOS's.

Digging around the problem, I came to know about the weak link thing for a framework, and uploaded the updated build to app store.

The idea is that, If you are using a framework that is not available to all the devices that you have selected as target devices, make the framework as weak link.

This can be done as below:

* Select the project target > Right click > Get-Info.

* Go to general tab > Linked libraries.

* Select the framework and make it a weak link.

Right click on the target ans select info.

Select weak link from type column.

Also, keep in if you mark a framework as weak linked, be sure to check for its availability before using any of its functionally.

You can check for the existence of the class like below code sample:

Class theClass = (NSClassFromString(@"UILocalNotification"));

if(theClass){

// Class exists

}

else{

// Class does not exists

}

Symbolicate crash logs

2011-02-03T11:53:00.000+05:30

Symbolicating of crash logs is the process of converting the HEX addresses into readable symbols (class/method names).
It is helpful to resolve the crashing issues of your application.
The crash logs for live appStore application can be retrieved from iTuneConnect web portal.
And during testing of your application the crash logs are retrieved from device by syncing the device with itune application. After sync. crash logs are stored in system at "~/Library/Logs/CrashReporter/MobileDevice/" for Mac OSx and at "C:\Users\\AppData\Roaming\Apple computer\Logs\CrashReporter/MobileDevice/" for Windows7 PC.

The crash log may seem as below:

Digging about reading the crash logs, here are the steps to get the class/method names in the .crash file.

1. Sync the device with your system.

2. Create a folder on the desktop, say "crashFiles",just to keep all files at one place.

3. Paste AppName.app.dSYM files to "crashFile" folder.

(Note: This file is created through xCode in your release folder)

4. Copy the .symbolicatecrash file in your system from the location "/Developer/Platforms/iPhoneOS.platform/Developer/Library/PrivateFrameworks/DTDeviceKit.framework/Versions/A/Resources/" & paste the file to "carshFile" folder on desktop.

5. Locate the .Crash file in your system. Following are the paths for .Crash file in different OS.

- Mac OS X : ~/Library/Logs/CrashReporter/MobileDevice/
- Windows XP: C:\Documents and Settings\\Application Data\Apple computer\Logs\CrashReporter/
- Windows Vista: C:\Users\\AppData\Roaming\Apple computer\Logs\CrashReporter/MobileDevice/
- Paste the .crash file in "crashFile" on desktop.
6. Start "terminal" from spotlight or Utilities folder in Applictions folder.
7. Run the below command with absolute path to all files:
- $ symbolicatecrash AppName.crash AppName.app.dSYM > report-with-symbols.crash

OR
- Drag and Drop symbolicatecrash file on terminal.

- Drag and Drop .crash file on terminal.

- Drag and Drop .app.dSYM file on terminal.
8. Now type ">report-with-symbols.crash" and hit enter.

Running above command will create a .Crash file "report-with-symbols.crash" replacing the symbols with more descriptive class/function name to dig in. The generate file may seem like below:

Happy coding...