iOS Development For Beginners

How to find a KEY from NSDictionary?

2012-12-16T23:15:00.003-08:00

Here we will take NSMutableArray with objects and NSDictionary with Objects and Keys.

NSMutableArray* mArray = [[NSMutableArray alloc]

initWithObjects:@"A",@"B",@"C",@"D",@"E",@"F", nil];

NSMutableDictionary *mDic = [NSMutableDictionary

dictionaryWithObjectsAndKeys:@"F",@"mF",@"G",@"mG",@"B",@"mB",@"I",@"mI",nil];

We will write a Function which can provide us the array of founded keys after comparison.

-(NSMutableArray*)compareMyObject:(NSMutableArray*)array:(NSDictionary*)dic

{

NSMutableArray* keysArray = [[NSMutableArray alloc] init];

for(int k=0;k<[array count];k++)

{

NSString* mStr = [array objectAtIndex:k];

NSArray* array = [dic allKeysForObject:mStr];

if([array count])

{

[keysArray addObject:[array objectAtIndex:0]];

}

return keysArray;

}

Now we will call this method in the following format.

NSMutableArray* keysArray = [self compareMyObject:mArray:mDic];

The above method gives us the result array now, We will print and check those results.

NSLog(@"total %d keys found. Those are %@",[keysArray count],[keysArray description]);

The result is :

keysArray = (

mB,

)

How to capture the screen with frame specific?

2012-02-01T20:07:00.000-08:00

    CGRect mRect = CGRectMake(0,0,730,905);
    UIGraphicsBeginImageContext(mRect.size);
    [self.containerView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

mRect is any frame which you wanted to take screen shot and containerview is the view where we need to take the screenshot.

A small examples with Animations

2012-02-01T05:12:00.000-08:00

In iOS Sdk there are two types of animation which is used frequently.

with CoreAnimation

            CATransition *animation = [CATransition animation];
            [animation setDuration:1.5];
            [animation setType:kCATransitionMoveIn];
            [animation setSubtype:kCATransitionFromRight];
            [animation setSpeed:1.5];
            [[imageView layer] addAnimation:animation forKey:nil];

Here imageView is the view where you need to apply the animation. the view with come from right to left with the specific duration.

setDuration - to set the animation happen time
setType - to set the animation type

see CATransition class to get more details.

with UIAnimation

        [UIView beginAnimations:nil context:nil];
        [UIView setAnimationDuration:2.0];
        [UIView setAnimationDelay:1.0];
        [UIView setAnimationDelegate:self];
        myImageView.alpha = 0.0;
        [UIView commitAnimations];

Here i wanted to hide the myImageview. Instead of hiding with
    myImageView.hidden = YES;
I thought of adding some animation to hide the view.
It will hide the view in 2 sec after 1 sec of delay.

We have delegate methods to use more effectively. Just have a look at the Class.

How to print the Frame(CGRect) of a View?

2012-02-01T04:57:00.000-08:00

NSLog(@"self.view.Frame=%@", NSStringFromCGRect(self.view.frame));

Here self.view is the view of UIView Class. You can print any frame with this log.

jSon Parse

2011-04-18T08:04:00.000-07:00

First Import the ASIHttpRequest Classes into our project.

        ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:location_cookie_url];
        [request setDelegate:self];
        request.shouldRedirect = NO;
        [request startAsynchronous];

- (void)requestFinished:(ASIHTTPRequest*)request
{
        if ([[[request responseHeaders] objectForKey:@"Set-Cookie"] hasPrefix:@"Preferences"])
        {

            ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:current_client_url];
            NSString*Strr = [NSString stringWithFormat:@"{\"IsMobile\": true, \"offerGuid\": \"%@\"}",[self.mProduct objectForKey:@"Guid"]];

            NSLog(@"%@",Strr);

            [request appendPostData:[Strr dataUsingEncoding:NSUTF8StringEncoding]];
            [request setDelegate:self];
            [request addRequestHeader:@"Content-Type" value:@"application/json; charset=utf-8"];
            [request startAsynchronous];
        }
}

- (void)requestFailed:(ASIHTTPRequest*)request
{
}

How to reduce the distance between sections in UITableview

2011-01-20T07:07:00.001-08:00

Use all these methods to reduce the height between sections in tableview

-(CGFloat)tableView:(UITableView*)tableView heightForHeaderInSection:(NSInteger)section
{
      return 3.0;
}

-(CGFloat)tableView:(UITableView*)tableView heightForFooterInSection:(NSInteger)section
{
    return 3.0;
}

-(UIView*)tableView:(UITableView*)tableView viewForHeaderInSection:(NSInteger)section
{
    return [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 0, 0)] autorelease];
}

-(UIView*)tableView:(UITableView*)tableView viewForFooterInSection:(NSInteger)section
{
    return [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 0, 0)] autorelease];
}

Application should run on background or not

2011-01-20T03:17:00.001-08:00

Open your info.plist file
Add The Key UIApplicationExitsOnSuspend or Select Application does not run in background
Set the new key to YES or Fill in the tick box

How to disable the sleep mode

2011-01-19T00:40:00.001-08:00

[[UIApplication sharedApplication] setIdleTimerDisabled:YES];

Digital Font for the Label

2011-01-17T23:14:00.001-08:00

[myLabel setFont:[UIFont fontWithName:@"DBLCDTempBlack" size:42.0]];

Generate Random Number in a given range

2011-01-14T09:33:00.000-08:00

TestViewController.h


#define RANDOM_SEED() srandom((unsigned)(mach_absolute_time() & 0xFFFFFFFF))
#define RANDOM_NUM() (random())

@interface TestViewController : UIViewController
...

TestViewController.m

#include <mach/mach_time.h>

@implementation TestViewController

-(int)getRandomNumber
  {


RANDOM_SEED();
int randomSelect=RANDOM_NUM()%([yourArray count]-1); // picks a random number in range 0 to count

return randomSelect;
}

May be useful

2011-01-14T06:34:00.000-08:00

How to disable sleep mode when you close the lid on your Mac laptop

http://www.simplehelp.net/2008/06/30/how-to-disable-sleep-mode-when-you-close-the-lid-on-your-mac-laptop/

Add badge value to tab bar item

2011-01-13T06:10:00.001-08:00

It will display on the specific TabItem's top right corner.

[[self.navigationController tabBarItem] setBadgeValue:@"5"];

Search Bar with Clear Background

2011-01-12T05:25:00.001-08:00

    UISearchBar* mSearchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0,160,320,40)];
    mSearchBar.showsCancelButton = NO;
    mSearchBar.userInteractionEnabled = YES;
    mSearchBar.backgroundColor = [UIColor clearColor];
    mSearchBar.tintColor = [UIColor whiteColor];
    mSearchBar.showsScopeBar = NO;
    [self.view addSubview:mSearchBar];

    for (UIView *subview in mSearchBar.subviews)
    {
        if ([subview isKindOfClass:NSClassFromString(@"UISearchBarBackground")])
        {
            [subview removeFromSuperview];
            break;
        }
    }

How to handle multiple textFileds

2011-01-12T04:05:00.000-08:00

In Load View,

   for(int i=0;i<8;i++)
        {
            UITextField* Field = [[UITextField alloc] initWithFrame:CGRectMake(150,44+35+40*i,160,30)];
            Field.borderStyle = UITextBorderStyleRoundedRect;
            Field.delegate = self;
            Field.tag = i+1;
            [self.view addSubview:Field];
            [mTextFiledsArray addObject:Field];
            [Field release];
        }

Use these Delegate methods,

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.3];
    if(textField.tag == 5) self.view.frame = CGRectMake(0,-20,320,480);
    else if(textField.tag == 7) self.view.frame = CGRectMake(0,-95,320,480);
    else if(textField.tag == 8) self.view.frame = CGRectMake(0,-130,320,480);
    [UIView commitAnimations];
    return YES;
}

- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    for(int i=0;i<[mTextFiledsArray count];i++)
    {
        UITextField* tf = [mTextFiledsArray objectAtIndex:i];
        if(textField == tf)
        {
            if(i+1 < [mTextFiledsArray count])
                [[mTextFiledsArray objectAtIndex:i+1] becomeFirstResponder];
            else
            {
                [UIView beginAnimations:nil context:nil];
                [UIView setAnimationDuration:0.3];
                self.view.frame = CGRectMake(0,0,320,480);
                [UIView commitAnimations];
                [textField resignFirstResponder];
            }
        }
    }
    return YES;
}

Add Custom Title to UINavigationBar

2011-01-11T08:40:00.000-08:00

    UILabel * label = [[[UILabel alloc] initWithFrame:CGRectMake(0,0,45,45)] autorelease];
   label.textColor = [UIColor grayColor];
   label.backgroundColor=[UIColor clearColor];
   label.font = [UIFont boldSystemFontOfSize:20];
   self.navigationItem.titleView = label;
   label.text=@"Search"; //CUSTOM TITLE
   [label sizeToFit];
    [label release];

UIApplication Methods

2011-01-10T08:54:00.000-08:00

    [UIApplication sharedApplication].statusBarHidden = NO;   // To Hide/Unhide the status bar.
    [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleBlackTranslucent; //To set the Style to status bar.
    [UIApplication sharedApplication].statusBarOrientation = UIDeviceOrientationPortrait; //To set the Device Orientation.

We can write
[UIApplication sharedApplication].statusBarHidden this as
    [[UIApplication sharedApplication] setStatusBarHidden:NO];