Programming life

Debug Android app with adb without connect to USB cable

2017-03-07T22:33:00.000-08:00

Sometimes, you might not be able to use the USB port for debugging your Android app. For example, you work with an app which reads from a flash memory via the USB port on the Android mobile. You have to use the Wifi instead.

Do it in the terminal like this.

1. Get your mobile's ip address

$ adb shell ip addr show wlan0

2. Connect to your mobile by ip. E.g. its ip is 192.168.1.22

$ adb connect 192.168.1.22

This sometimes gives connection refused error.

Run this command then run the adb connect ipaddress command again. It should be fine.

$ adb forward tcp:5555 tcp:5555

3. Check your devices

$ adb devices

You should see two devices connected. One has a serial number and one has the ip address. Both are the same mobile.

4. Unplug your mobile and check device one more time. You should see only one device with its ip address. Now you can begin to debug your app.

$ adb devices

Choose the connected mobile in Android Studio and run your app. Debug information still shows on the Android monitor when you are connecting to your mobile via Wifi.

Check packages installed in the mobile:

$ pm list packages -f

Log library comparison

2017-03-01T04:06:00.002-08:00

Log

Log4cpp - A library of C++ classes for flexible logging to files, syslog, IDSA and other destinations (LGPL). It is modeled after the Log4j Java library
http://log4cpp.sourceforge.net/.
spdlog - Super fast, header only, C++ logging library. Cross-platform.
plog - Portable and simple log for C++ in less than 1000 lines of code (MPL2)
Boost - c++ library for logging is very slow (http://stackoverflow.com/questions/3510473/experience-using-boost-log-logging-library) heavy weight and just kind of complicated
G3log is asynchronous "crash safe" logger. Fatal events such as segmentation faults can be caught and before shutting down the process a stack dump is saved to your log. G3log is cross-platform and used on at least multiple Linux flavors, OSX and Windows. You will find it here: https://github.com/KjellKod/g3log. It comes with a default file logging sink. More sinks are available at:https://github.com/KjellKod/g3sinks. In a recent high-contention performance test g3log showed average LOG API calls of 2-3 us. Compared to another, on average faster logger, g3log showed very consistent and small worst case wait times. https://kjellkod.wordpress.com/2...
glog - https://github.com/google/glog
SergiusTheBest/plog is a very simple and elegant logging library for C++.

DIY

If you wanted to write something faster consider your own design with a lockless cocurrent queue and a background thread to deal with the data.

My Choice
I worked for a project and tried spdlog for logging on both iOS and Android platform. The spdlog is used inside the Djinni framework. It works very nice and easy to handle. It logs both the log file and console and supports multithread.

Useful tips for blogging code

2016-07-27T11:48:00.002-07:00

I have hoped to know how to put code nicely in my blog. Now I finally get it.

The code should be wrapped in <pre><code> </code></pre> block.

If you check the html code for the following text, you can see how it is in html.


public void test(){

I learned it from this webpage https://css-tricks.com/posting-code-blocks-wordpress-site/.

Now it is time for Firebase

2016-07-26T22:14:00.000-07:00

Firebase comes! I tried it and find it is quite handy to use. I put two tutorials about sending push notifications with Firebase for Android on CodeMentor here.

https://www.codementor.io/android/tutorial/send-push-notifications-to-android-with-firebase

https://www.codementor.io/android/tutorial/send-push-notifications

How to select a row automatically in UITableView

2016-05-18T22:20:00.000-07:00

Sometimes you need to use UISplitterViewController which has one menu on the left and one detail view on the right. Both are tableviewcontrollers. Then you might want to select the first cell on the left hand automatically.

This code can help you to select the first menu cell. From http://stackoverflow.com/questions/2728152/select-first-row-as-default-in-uitableview





- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear:animated];

    if(IS_IPAD){

        NSIndexPath *indexPath=[NSIndexPath indexPathForRow:0 inSection:0];

        [self.tableView selectRowAtIndexPath:indexPath animated:YES  scrollPosition:UITableViewScrollPositionBottom];

        [self performSegueWithIdentifier:@"menuToDetail" sender:self];

    }

}

I added the code from the suggestion in the Stackoverflow and added perform segue to the detailView. Then it worked with

showing things correctly. Remember that you must check if it is on the iPad because

this crashes your iPhone version since the splitterview is not used in the iphone

version.

Lessons Learned for Android App Release

2016-04-28T22:27:00.002-07:00

Yesterday I had a lot of problem with release an update to my app GSOplay.
It was tedious but I have got some more experience with releasing an Android app.

1. Always Check "Supported Android devices"
When uploading an APK, it is very important to click the "APK details" before clicking "Publish" button. Here you must check if the "supported devices" is more than 0. If it is 0, don't publish it. Otherwise, the app will disappear in the Google Play Store.
The reason of "supported Android devices" 0 can be that you use a library which is not accepted as a library for mobile apps. For example, if you have apache.common.io library in your gradle file, it will make "Supported Android devices" to be 0, which is not what we want.

2. Error happens, but what is the error?
If you get a warning when uploading an apk file, saying that error happens without marking any error in the uploading form. Do like this: click button "Save as draft" beside the "Publish" button. Then the error will show up.

3. targetSdkVersion
The latest release cannot have a targetSdkVersion which is lower than previous versions. If you have version 1.5 with targetSdkVersion 23 and want to upload version 1.6 with targetSdkVersion 19. You will fail when publishing the app. The targetSdkVersion in the latest version should always >= the targetSdkVersion in previous versions.

4. Google Play Store Releasing Time
After you have uploaded an update of your app to the Play Store, it takes time to update the app in the Play Store. So it doesn't show a new version directly. Even sometimes it takes only some minutes to see the new version in the Play Store. Most time it doesn't update so fast. Sometime the console can show that the update is submitted. But the Play Store still shows the earlier version. Don't panic. It needs time to sync everything. Have a break for half a day or just go to sleep. The app will be there finally.

5. Worst Scenario
Things sometimes don't go smoothly. Sometimes it just doesn't work well. Do this:

Step 0: Be calm. Have a deep breath. Believe that everything can be solved.

Step 1: If this is a custom-made app, call your customer that there is some issue with the app release and describe the situation to get understanding.

Step 2: Google the problem that you have accoutered and see if there is similar problem and the solution.

Step 3: If it still does not work, report to Google about the problem and try to get help.

https://support.google.com/googleplay/android-developer/troubleshooter/3055196?hl=en

https://support.google.com/googleplay/android-developer/contact/publishing?extra.IssueType=missing

That's all I have learning with my app release yesterday. Hope it will be helpful for you.

The biggest panic today - Supported device 0 !!!

2016-04-28T09:28:00.001-07:00

It is always like taking roller-coaster when developing Android apps. This is quite unfortunate for an app developer. Specially at a gray rainy day today, slept badly, caught a cold, quarreled with my kid because he didn't want to go to school this morning and had a user complaining his app not working.
After all the troubles, I got the problem - "Supported device 0" in publishing Android app in production, which just became the last straw that almost broke my heart and nerve.

No complain when I made an APK file in Android Studio and publish it. But when I checked the Google Play Store to find the updated app, I couldn't find it! In all my Android devices! Then when I came back to the console for Production, I found the information about 0 supported device.

One more time Stack Overflow saved my life.

I found the solution:
This line in my build.gradle is the killer.

compile 'org.apache.directory.studio:org.apache.commons.io:2.4

So I removed it , recompiled my apk and uploaded to Google again. Now it supports all the devices.

I just wonder how come this cannot be found during compilation. If Android Studio doesn't accept apache.commons library, why not just warning at the very beginning? It is such a waste of time to troubleshoot it. And I am sure that I am not the last developer who get such problem.

After all these struggle, I guess I am closer to an iron woman.

Reference: http://stackoverflow.com/questions/33308560/supported-android-devices-0-devices

The biggest headache from Android SDK 23.2.0

2016-04-10T21:48:00.004-07:00

I have worked hours for solving a crash problem for my Android app. My app works fine in Android 5.1 devices but not 4.4.

The error is like this:

android.view.InflateException: Binary XML file line #36: Error inflating class android.support.v7.widget.Toolbar

...

Caused by: android.view.InflateException: Binary XML file line #36: Error inflating class android.support.v7.widget.Toolbar

....

Caused by: android.content.res.Resources$NotFoundException: File res/drawable-v19/abc_ic_ab_back_material.xml from drawable resource ID #0x7f02001c

I struggled a lot with the theme. Finally, I found out that it is something that should be changed in gradle when you update to Android SDK 23.2.0.

This can be fixed by change the settings in Gradle, depending on the Gradle version you use. For the new, 2.0 Gradle plugin it is a one liner:

// Gradle Plugin 2.0+  
 android {  
   defaultConfig {  
     vectorDrawables.useSupportLibrary = true  
    }  
 }

And for Gradle version 1.5 (there is no such fix for older Gradle versions):

// Gradle Plugin 1.5  
 android {  
   defaultConfig {  
     generatedDensities = []  
  }  

  // This is handled for you by the 2.0+ Gradle Plugin  
  aaptOptions {  
    additionalParameters "--no-version-vectors"  
  }  
 }

This link has detailed description

http://blog.autsoft.hu/do-this-when-upgrading-to-support-library-23-2/

But I have to say that the biggest headache reveals the big change in Android SDK for dealing with images. After Lollipop you can use vector images in an Android app! That's so great!
http://android-developers.blogspot.se/2016/02/android-support-library-232.html#uds-search-results

Save styled receiver on google drive

2016-04-05T07:19:00.001-07:00

When I work with styled receiver for Chromecast, I had some failure and success. So I share my experience here.

It is boring to use the ready made style for Chromecast receiver, which only shows the name of your app and dark background. So it is good to upload your own style.css for your receiver. This link is configured under your cast app at the https://cast.google.com/.

However, google doesn't give you a host automatically at the cast.google.com. You need to save all the files - style.css and its relevant files in a Https server. If you have not a https server, a good solution is to use drive.google.com but it is a little tedious.

Remember the baseline : all the files - images, html, css, js files must use absolute links which starts with "https://www.googledrive.com/host/".

Now let's go to the Google Drive and create a folder A for your files.

Step 1. Upload the images files (background.png, logo.png, splash.png ...) to the folder A in your Google drive. Click "share" to get the link of each image file like "https://drive.google.com/open?id=XXXXXXXX". Here you need to share the file as public and anyone can view it.
Copy the id and put it into this link like this "https://www.googledrive.com/host/XXXXXXXX". This link is the absolute link that you will be able to reach from the style.css file. This is very important. Forget all the extra stuff that you get from the shared link in Google Drive. Only use the id at the last part of the link.

Step 2. Put the absolute links into the style.css file. Its content should look like this

.background {

background: center no-repeat url(https://www.googledrive.com/host/FDAFEHHHTTFEFE);

}

.logo {

background-image: url(https://www.googledrive.com/host/FADFEEADFEFFF);

}

.progressBar {

background-color: #A0000F;

}

.splash {

background-image: url(https://www.googledrive.com/host/ZDFDFDEFAFAFE);

}

Step 3. Then publish the style.css file on drive.google.com.

Step 4. Do the same change for the link of the style.css file. Here you need to share the file as public and anyone can view it. More details is on the following link.

Reference : https://support.google.com/drive/answer/2881970?hl=en

Step 5. Now you can use the link of the style.css for your app at the https://cast.google.com/.

Now you can run your app and see if the interface on the TV is changed. Notice: any newly registered cast app won't work at once. You have to wait some hours for the new cast app to work. But if you already have one styled receiver app registered, you can test it directly. If no updates are shown, you can restart your Chromecast device with Google Cast app installed on your mobile.

Checklist before release iOS app

2016-03-04T12:51:00.002-08:00

It has been some months since I uploaded a completely new app. Tonight I struggled a lot with different problem during release of an iPad app.

After I struggled for some time, I found out that I forgot to add a new app in "My Apps" in my member center. What a miss! Then got some other problems so I put them here to make the next release more correct.

1. Add a new app in the member center in developer.apple.com

2. In your XCode project

Make icon images and add them in the asset in the project. (Notice, TV apps need even more images - large icon, small icon, top shelf image, launch image. Specially, top shelf image must has its alpha channel turned off. This can be done with Preview. )

Add one key in info.plist UIRequiresFullScreen and make it YES. (This will remove possible error - iPad multitasking support requires three orientations during archiving)
Add one key in info.plist ITSAppUsesNonExemptEncryption and make it NO. Otherwise, even you can upload it to the App Store, still they tell you go back and add this key :( This is new requirement as far as I know. It was ok to answer encryption related question when configuring apps in the web page last year. Today is 2016-3-4.

This is what I learned in 2 hours at a Friday night - by a tired app developer.

Images can't contain alpha channels or transparencies - for iOS release

2016-02-25T01:15:00.000-08:00

This error happens so often and I just need to put it in my blog to remember it.

When I upload an iOS app to the App Store, this always jump out because the app icon image that I use is png image with transparency. The error can extend even more when I develop TV apps because the "Top Shelf Image" requires also an image with NO transparency.

The simplest way is to use jpg. But due to the loss of image quality of jpg format, it might be safer to use a png image without transparency. For Mac users, the easiest way is to re-export the png's in Preview, but uncheck the Alpha checkbox when saving.

The credit goes to Smikey at http://stackoverflow.com/questions/25681869/images-cant-contain-alpha-channels-or-transparencies. Thanks for the solution!

New problem in releasing and solution - for iOS apps

2016-02-24T23:31:00.002-08:00

This morning a new problem came when I tried to upload a TV app to the App Store. The error message is "Missing iOS Distribution signing identity for xxxx".

I thought that it is because I made some provision profile messy. But it wasn't. Apple's WWDR intermediate certificate which became expired. So it is simple to solve it.

1. In the Key Chain Access, View->Show Expired Certificates, then System->All Items. Find the "Apple Worldwide Developer Relations Certification Authority". Check the expiration time. If it is expired, delete it.

2. Download https://developer.apple.com/certificationauthority/AppleWWDRCA.cer

3. Install the new certificate and then all the problems are gone!

I found the solution here and inspired by Teja Kumar Bethina:
http://stackoverflow.com/questions/32821189/xcode-7-error-missing-ios-distribution-signing-identity-for

Worst news ever- Parse is dead

2016-01-28T23:40:00.001-08:00

This is a shocking news. Parse will end its service on 28 Jan 2017. I saw this news when I woke up this morning and checked my email in my bed. This news made me awake at once and called my partner in my company.
I have several apps using Parse service. It is so convenient and nice to save a lot of time in development. I am so grateful that I hope to pay for the service. But it is too generous that it cannot afford its own expense. I am so sad to get the news. Why can't Facebook just let others to buy it or begin to change the pricing solution? It is so cruel to stop a service like this. Ok, it is good to let us know one year ahead. But anyway, I cannot find a better service than Parse in the world. Even I would like to pay for such a service.

From today it is time to only rely on myself - make my own backend and never rely on any other service.

Just have to mourn for Parse in this dark rainy Friday.

My Course about Google In-app Billing is in PluralSight now!

2016-01-24T08:57:00.001-08:00

My Course about Google In-app Billing is in PluralSight now! It took me a lot of time to develop this course. If you work with Android app and are curious about Google In-app Billing, please check my course here.

https://app.pluralsight.com/library/courses/google-play-in-app-billing/table-of-contents

Apple TV 4 Apps and Gaming

2016-01-24T08:54:00.000-08:00

I have begun to work with Apple TV app. It is very interesting and I made some basic introduction videos for normal Apple TV users and developers. I will make more videos about TV app development later when I get some time.

For Apple TV Users

A Quick Look at Apple TV 4

How to Use Apple TV 4

Gaming with Nimbus Controller for Apple TV 4

For Testers:

How to Test TV App in Apple TV

System Font - TV OS

2016-01-19T12:00:00.001-08:00

It is useful to know the font names. When I ran the following code that I found on http://giordanoscalzo.tumblr.com/post/95900320382/print-all-ios-fonts-in-swift :

func printFonts() {

let fontFamilyNames = UIFont.familyNames()

for familyName in fontFamilyNames {

print("------------------------------")

print("Font Family Name = [\(familyName)]")

let names = UIFont.fontNamesForFamilyName(familyName as! String)

print("Font Names = [\(names)]")

}

I get the list of fonts. It could be useful sometimes.

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

Font Family Name = [Kohinoor Telugu]

Font Names = [["KohinoorTelugu-Light", "KohinoorTelugu-Medium", "KohinoorTelugu-Regular"]]

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

Font Family Name = [Heiti SC]

Font Names = [[]]

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

Font Family Name = [Symbol]

Font Names = [["Symbol"]]

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

Font Family Name = [Courier]

Font Names = [["Courier-BoldOblique", "Courier", "Courier-Bold", "Courier-Oblique"]]

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

Font Family Name = [Apple Color Emoji]

Font Names = [["AppleColorEmoji"]]

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

Font Family Name = [Avenir Next]

Font Names = [["AvenirNext-DemiBold", "AvenirNext-UltraLight", "AvenirNext-Regular", "AvenirNext-HeavyItalic", "AvenirNext-BoldItalic", "AvenirNext-MediumItalic", "AvenirNext-Italic", "AvenirNext-Heavy", "AvenirNext-DemiBoldItalic", "AvenirNext-Bold", "AvenirNext-UltraLightItalic", "AvenirNext-Medium"]]

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

Font Family Name = [Arial Hebrew]

Font Names = [["ArialHebrew-Light", "ArialHebrew", "ArialHebrew-Bold"]]

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

Font Family Name = [Telugu Sangam MN]

Font Names = [[]]

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

Font Family Name = [Helvetica Neue]

Font Names = [["HelveticaNeue-UltraLight", "HelveticaNeue-UltraLightItalic", "HelveticaNeue-LightItalic", "HelveticaNeue", "HelveticaNeue-Light", "HelveticaNeue-MediumItalic", "HelveticaNeue-CondensedBold", "HelveticaNeue-CondensedBlack", "HelveticaNeue-Thin", "HelveticaNeue-ThinItalic", "HelveticaNeue-Medium", "HelveticaNeue-Italic", "HelveticaNeue-BoldItalic", "HelveticaNeue-Bold"]]

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

Font Family Name = [Trebuchet MS]

Font Names = [["TrebuchetMS-Italic", "TrebuchetMS-Bold", "Trebuchet-BoldItalic", "TrebuchetMS"]]

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

Font Family Name = [Bangla Sangam MN]

Font Names = [[]]

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

Font Family Name = [Heiti TC]

Font Names = [[]]

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

Font Family Name = [Hiragino Sans]

Font Names = [["HiraginoSans-W6", "HiraginoSans-W3"]]

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

Font Family Name = [Tamil Sangam MN]

Font Names = [["TamilSangamMN", "TamilSangamMN-Bold"]]

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

Font Family Name = [PingFang TC]

Font Names = [["PingFangTC-Semibold", "PingFangTC-Medium", "PingFangTC-Regular", "PingFangTC-Ultralight", "PingFangTC-Light", "PingFangTC-Thin"]]

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

Font Family Name = [Times New Roman]

Font Names = [["TimesNewRomanPS-ItalicMT", "TimesNewRomanPS-BoldItalicMT", "TimesNewRomanPSMT", "TimesNewRomanPS-BoldMT"]]

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

Font Family Name = [Kohinoor Devanagari]

Font Names = [["KohinoorDevanagari-Light", "KohinoorDevanagari-Regular", "KohinoorDevanagari-Semibold"]]

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

Font Family Name = [Kohinoor Bangla]

Font Names = [["KohinoorBangla-Regular", "KohinoorBangla-Semibold", "KohinoorBangla-Light"]]

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

Font Family Name = [Thonburi]

Font Names = [["Thonburi", "Thonburi-Bold", "Thonburi-Light"]]

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

Font Family Name = [Gujarati Sangam MN]

Font Names = [["GujaratiSangamMN-Bold", "GujaratiSangamMN"]]

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

Font Family Name = [Geeza Pro]

Font Names = [["GeezaPro-Bold", "GeezaPro"]]

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

Font Family Name = [Lao Sangam MN]

Font Names = [["LaoSangamMN"]]

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

Font Family Name = [Sinhala Sangam MN]

Font Names = [["SinhalaSangamMN-Bold", "SinhalaSangamMN"]]

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

Font Family Name = [Courier New]

Font Names = [["CourierNewPSMT", "CourierNewPS-BoldItalicMT", "CourierNewPS-BoldMT", "CourierNewPS-ItalicMT"]]

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

Font Family Name = [Malayalam Sangam MN]

Font Names = [["MalayalamSangamMN", "MalayalamSangamMN-Bold"]]

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

Font Family Name = [PingFang SC]

Font Names = [["PingFangSC-Regular", "PingFangSC-Ultralight", "PingFangSC-Thin", "PingFangSC-Medium", "PingFangSC-Light", "PingFangSC-Semibold"]]

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

Font Family Name = [Apple SD Gothic Neo]

Font Names = [["AppleSDGothicNeo-Thin", "AppleSDGothicNeo-SemiBold", "AppleSDGothicNeo-Light", "AppleSDGothicNeo-Medium", "AppleSDGothicNeo-Bold", "AppleSDGothicNeo-UltraLight", "AppleSDGothicNeo-Regular"]]

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

Font Family Name = [Euphemia UCAS]

Font Names = [["EuphemiaUCAS", "EuphemiaUCAS-Bold", "EuphemiaUCAS-Italic"]]

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

Font Family Name = [PingFang HK]

Font Names = [["PingFangHK-Regular", "PingFangHK-Medium", "PingFangHK-Thin", "PingFangHK-Semibold", "PingFangHK-Light", "PingFangHK-Ultralight"]]

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

Font Family Name = [Menlo]

Font Names = [["Menlo-BoldItalic", "Menlo-Italic", "Menlo-Regular", "Menlo-Bold"]]

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

Font Family Name = [Kailasa]

Font Names = [["Kailasa", "Kailasa-Bold"]]

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

Font Family Name = [Khmer Sangam MN]

Font Names = [["KhmerSangamMN"]]

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

Font Family Name = [Avenir]

Font Names = [["Avenir-Book", "Avenir-Heavy", "Avenir-BlackOblique", "Avenir-Black", "Avenir-LightOblique", "Avenir-BookOblique", "Avenir-Light", "Avenir-Medium", "Avenir-HeavyOblique", "Avenir-Oblique", "Avenir-Roman", "Avenir-MediumOblique"]]

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

Font Family Name = [Savoye LET]

Font Names = [["SavoyeLetPlain"]]

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

Font Family Name = [Zapf Dingbats]

Font Names = [["ZapfDingbatsITC"]]

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

Font Family Name = [Kannada Sangam MN]

Font Names = [["KannadaSangamMN-Bold", "KannadaSangamMN"]]

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

Font Family Name = [Copperplate]

Font Names = [["Copperplate", "Copperplate-Light", "Copperplate-Bold"]]

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

Font Family Name = [Gurmukhi MN]

Font Names = [["GurmukhiMN", "GurmukhiMN-Bold"]]

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

Font Family Name = [Iowan Old Style]

Font Names = [["IowanOldStyle-Italic", "IowanOldStyle-Bold", "IowanOldStyle-BoldItalic", "IowanOldStyle-Roman"]]

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

Font Family Name = [Oriya Sangam MN]

Font Names = [["OriyaSangamMN-Bold", "OriyaSangamMN"]]

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

Font Family Name = [Helvetica]

Font Names = [["Helvetica-Oblique", "Helvetica-Bold", "Helvetica-LightOblique", "Helvetica-BoldOblique", "Helvetica-Light", "Helvetica"]]

A Nasty Problem with Android Project using Parse Framework

2015-11-12T04:59:00.004-08:00

I have had problem when I compiled my Android project which uses Parse Framework 1.10.1. It had worked before but all in a sudden it cannot compile.

The error is like:

Error:Execution failed for task ':xxxx App :packageAllDebugClassesForMultiDex'.
java.util.zip.ZipException: duplicate entry: bolts/AppLink$Target.class

I searched the internet and found the saver here http://stackoverflow.com/questions/28791817/android-studio-gradle-error-multiple-dex-files-define

The solution is to change the bolts version to the specific version that you are using in your Gradle file.

I changed mine from compile 'com.parse.bolts:bolts-android:1.+'

to compile 'com.parse.bolts:bolts-android:1.2.1'

Then it just works!

Welcome to iOS9! - Issues Collection

2015-09-20T02:48:00.004-07:00

iOS 9 has been installed in more and more mobiles recently. Do you want to have a crashing app in iOS 9? Definitely not. So check if your apps can run in the new simulators.
I found several issues in my case. Some are issues, some are just because I haven't read all the document and watched the WWDC videos.

Issue 1. Parse not showing images.

I use Parse as my mobile backend service and store some images and texts there. Texts can be loaded but not images. So I found a good fix from here:

http://stackoverflow.com/questions/31078767/images-from-parse-not-loading-on-ios-9

This is probably due to SSL requirements with iOS 9. Since Parse doesn't use HTTPS for files, they won't download correctly. Set the info.plist to include keys such as this, which turn off the SSL requirements...at your own risk, of course:

<key>NSAppTransportSecurity</key>

<dict>

<key>NSAllowsArbitraryLoads</key>

<true/>

<key>NSExceptionDomains</key>

<dict>

<key>files.parsetfss.com</key>

<dict>

<key>NSIncludesSubdomains</key>

<true/>

<key>NSTemporaryExceptionAllowsInsecureHTTPLoads</key>

<true/>

<key>NSTemporaryExceptionMinimumTLSVersion</key>

</dict>

Issue 2. Where is .dylib ?

Some .dylib frameworks become red, which means that they are not linked correctly. Although my project still compiles, I must fix it. Found a good solution on Stackoverflow.

http://stackoverflow.com/questions/30815806/swift-2-ios-9-libz-dylib-not-found

Go to Build Phases >Link Binary with Librairies > + > Add other
Once in the file selection window do "CMD"+Shift+G (Go to folder) and type /usr/lib/
From /usr/lib you can add : libz.dylib and more...
Compile and have fun

More discussions here https://forums.developer.apple.com/message/8609#8609

Issue 3. Warning about supportedInterfaceOrientations

The function supportedInterfaceOrientations has different return type in iOS 9. A good solution is here: (reference: https://forums.developer.apple.com/thread/6165)

#if __IPHONE_OS_VERSION_MAX_ALLOWED < 90000
- (NSUInteger)supportedInterfaceOrientations {

}
#else
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {

}
#endif

Issue 4. Warnig itms 90474 ipad multitasking support ...
During uploading to App Store, this can happen.

Solution
If you must opt out of Slide Over and Split View, do so explicitly by adding the UIRequiresFullScreen key to your Xcode project’s Info.plist file and apply the Boolean value YES. You can do this in the property list editor or in the General > Deployment Info area in the target editor.

http://stackoverflow.com/questions/32557783/invalid-bundle-error
https://developer.apple.com/library/prerelease/ios/documentation/WindowsViews/Conceptual/AdoptingMultitaskingOniPad/QuickStartForSlideOverAndSplitView.html

Issue 5. Connect to Dropbox problems (or open URL problems)
In iOS9, an app calling Dropbox App cannot show content or choose files from Dropbox. It just asks you to install Dropbox, although it is already to installed.

Reason: Apple has added more privacy protection for apps. So one app cannot scan the apps installed in one user's mobile by opening URL schemes. The solution is to add URL schemes that you need to a white list in infolist.

Solution: You need to add the URL scheme for Dropbox. So add the following lines to the infolist of your app. It will work!

<key>LSApplicationQueriesSchemes</key>

<array>
<string>dbapi-3</string>

<string>dbapi-3</string>

</array>

https://www.dropbox.com/developers/chooser#ios

http://stackoverflow.com/questions/31454686/in-ios9-dropbox-app-is-not-being-opened-instead-webview-is-being-opened-for-log
https://www.macstories.net/linked/ios-9-bringing-changes-to-url-schemes/
http://useyourloaf.com/blog/querying-url-schemes-with-canopenurl.html

Issue 6. Contact book crashes sometimes

I have an app which reads out a user's contact and loads it to a view controller.

Error: Contact and its snapshot should both be non-unified
Reason: Apple has added privacy protection for contact book. It is a positive thing so I accept the shock that the crashes brought to me.

Solution:
Add these lines in viewDidLoad in the viewController which you open the contact book.

ABAddressBookRef addressBook = ABAddressBookCreateWithOptions(NULL, NULL);
ABAddressBookRequestAccessWithCompletion(addressBook, ^(bool granted, CFErrorRef error) {
NSLog(@"Access to contacts %@ by user", granted ? @"granted" : @"denied");
});

Reference:
https://forums.developer.apple.com/thread/11354
http://www.raywenderlich.com/97936/address-book-tutorial-swift-ios

Android Users Need to Know about the Security Threat - Stagefright

2015-08-30T12:27:00.001-07:00

A new vulnerability in Android is found - an attacker can use MMS to attack your mobile. If you want to know more about it, you can read here.

BBC news 28 July 2015

Android bug: MMS threat affects 'one billion' phones

The discoverer Joshua Drake made a presentation on this issue at the Blackhat Conference USA 2015

Fix your mobile's MMS

https://blog.lookout.com/blog/2015/07/30/how-to-disable-auto-fetching-of-mms-messages-on-a-devices-default-sms-app/

Use another OS

Install newest patch from Android. If it is too slow on your Android mobile's vendor, install some other Android OS, e.g. CyanogenMod, which has passed the test for this StageFright problem.

I just feel to get back my old Nokia 3310 after watching this video :(

Use Parse for Crash Report

2015-08-28T08:29:00.003-07:00

The XCode 6.3 has got the support for crash report function (read more here). But before you distribute an app to the App Store, how do you find out a crash? It is hard to let a normal user to send you crash report. Nobody knows how to do it.

Parse has made a nice service - ParseCrashingReport. With this service/framework, you can get the crash reports on the Parse.com's Analytics panel.

There is complete guide in https://parse.com/docs/ios/guide#crash-reporting. But I find that there are always some small details to add to that. The following is my experience with parse framework 1.8.2. The framework is always updating, so check their official link above to get the latest information.

The steps are like this:

Step 1.
Install / update Parse CLI in the Terminal

curl -s https://www.parse.com/downloads/cloud_code/installer.sh | sudo /bin/bash

Step 2.

Install cloud code folder in the same fold with the Xcode project. Run the following command in the Terminal

parse new

Step 3.
Build Phases-> Link Binary With Librarys

Add libraries: ParseCrashReporting.framework and libstdc++6.0.9.dylib

If any library is missing, the project cannot compile.

Step 4.
In AppDelegate.h, add this

#import <ParseCrashReporting/ParseCrashReporting.h>

In AppDelegate.m didFinishLaunchingWithOptions, add

[ParseCrashReporting enable];

before this line

[Parse setApplicationId:@"APPLICATION_ID" clientKey:@"CLIENT_KEY"];

Step 5.

Add the run script to build phase.

New run script:

export PATH=/usr/local/bin:$PATH

cd /Users/emma/Code/MyPlayer/

parse symbols MyPlayer --path="${DWARF_DSYM_FOLDER_PATH}/${DWARF_DSYM_FILE_NAME}"

Step 6.

Add a crash in AppDelegate.m and test it in release version. Do not run it in debug environment which will catch the exception.

Parse has given example code to make your app crash in https://parse.com/docs/ios/guide#crash-reporting.

Step 7.

Wait 5 minutes and go to your app's crash report page on Parse.com e.g. https://www.parse.com/apps/myplayer/crashes

If it doesn't show up, run the release version once again and wait for some time. It will show on your crash report like this.

Click into the error, you will get more interesting details.

NOTICE:
In step 2, my folder with the Xcode project is /Users/emma/Code/MyPlayer/
I have setup a cloud folder under the above folder which is called "cloudcode". But there are only /cloud and /public folders. This misses the /config folder which is normally added when a cloud folder is set up. So I had to make a /config folder and find another cloud folder to copy the global.json. The global.json is important because it makes your app able to login to the Parse server. It should look like this

{
"global": {
"parseVersion": "1.8.2" //this is the version I am using
},
"applications": {
"GSOplay": {
"applicationId": "your app id",
"masterKey": "your master key"
},
"_default": {
"link": "MyPlayer"
}
}

}

Scroll up a view when typing - iOS

2015-08-25T22:18:00.005-07:00

This is a common feature for most of the apps. When a UITextField is on the bottom of the view, it is not nice to type without seeing what is typed.

When I am working on a view where users filling their information, I found that I must scroll up the view.

An easy way is to use tableView. Then add some more methods which detect the keyboard. It works like this, scroll up the view when the keyboard is shown and scroll down when the keyboard is gone.

The code is like this

1. Add observers for keyboard in ViewDidLoad method

[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWasShown:) name:UIKeyboardDidShowNotification object:nil];

[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillBeHidden:) name:UIKeyboardWillHideNotification object:nil];

2. Detect the keyboard events

/* Scroll tableview up when typing

- (void)keyboardWasShown:(NSNotification *)aNotification

{

NSDictionary* info = [aNotification userInfo];

CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);

self.tableView.contentInset = contentInsets;

self.tableView.scrollIndicatorInsets = contentInsets;

}

/* Scroll tableview down when typing

- (void)keyboardWillBeHidden:(NSNotification *)aNotification

{

self.tableView.contentInset = UIEdgeInsetsMake(44.0, 0.0, -44.0, 0.0);
//the value 44.0 is for my case with a navigation bar on the top of the tableview. So I need to scroll down the table a little.

self.tableView.scrollIndicatorInsets = UIEdgeInsetsZero;

}

3. Unregister observers when dealloc

-(void)dealloc{

[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidShowNotification object:nil];

[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];

}

That's all!

Reference:

1. https://developer.apple.com/library/ios/documentation/StringsTextFonts/Conceptual/TextAndWebiPhoneOS/KeyboardManagement/KeyboardManagement.html

2. http://stackoverflow.com/questions/594181/making-a-uitableview-scroll-when-text-field-is-selected

How to check a string's content is a number in Android

2015-05-21T21:55:00.001-07:00

There are several methods to do this. I found that Stack Overflow has good solutions for this. To make it simple to read, I organise them here.

I prefer method isNumeric in solution 1. It is simple, small and no exception catching, which is best on performance.

Solution 1 (my favorite solution):

You can use TextWatcher for EditText to get value of every change in EditText.You need to add interface of TextWatcher in your Activity.

mEditText.addTextChangedListener(Your Class Name.this);

on in method of TextWatcher

@Override

public void afterTextChanged(Editable s) {

Log.v("Log_tag", "After TextChanged" + s.toString());

}

@Override

public void beforeTextChanged(CharSequence s, int start, int count,

int after) {

Log.i("Log_tag", "Before TextChanged" + s.toString());

}

@Override

public void onTextChanged(CharSequence s, int start, int before, int count) {

Log.e("Log_tag", "ontext Changed" + s.toString());

//you can match here s with number or integer

if(isNumeric( s.toString())){

//it is number

}

public static boolean isNumeric(String str)

{

return str.matches("-?\\d+(.\\d+)?");

}

Solution 2 :

This solution is very limited because it only checks 0-9 without considering "-" and ".". Note that this method returns true with empty String : Issue 24965.

Since API level 1, Android provides an helper method to do just that (no need to use regex or catching exception) : TextUtils.isDigitsOnly(CharSequence str)

boolean digitsOnly = TextUtils.isDigitsOnly(editText.getText());

Solution 3:

String text = editText123.getText().toString();

try {

int num = Integer.parseInt(text);

Log.i("",num+" is a number");

} catch (NumberFormatException e) {

Log.i("",text+"is not a number");

}

http://stackoverflow.com/questions/10120212/how-to-determine-if-an-input-in-edittext-is-an-integer

Make Button with Dynamic Color - Android Tutorial

2015-04-29T07:05:00.000-07:00

I made a video which explains how to make button with dynamic color or dynamic buttons.

Problem in importing address from address book in iOS8

2015-01-08T12:53:00.003-08:00

Things change all the time. Apple changes so many things which makes me really tired these days. I have to fix several apps which should adapt to iOS8.

I found one problem in my app. There is one function with which you can import one person's contact by clicking the person's name in the address book in the mobile. After iOS8, this doesn't work. After clicking the person's name, it leads to the details of the person's contact. It is not what I wanted!

The iOS8 has added a new delegate method which you have to implement if you want to keep the function works same as before.

- (void)peoplePickerNavigationController:(ABPeoplePickerNavigationController *)peoplePicker
didSelectPerson:(ABRecordRef)person{
}

It is quite obvious that the method is called when you click the person. Just move your previous code for importing contact inside here. Then you won't see the annoying contact details view :D

Just put my code here as an example so you don't get panic in searching google. It contains my own methods so don't copy everything ;)

- (void)peoplePickerNavigationController:(ABPeoplePickerNavigationController *)peoplePicker
didSelectPerson:(ABRecordRef)person{

AddressBookImport* importer = [[AddressBookImport alloc] init];
PersonalInfo* currentContact = [importer parsePerson:person];

// Update the settings
personInfo = currentContact;

// Dismiss the contacts view controller.
[_contacts dismissViewControllerAnimated:false completion:NO];

[self reloadInputViews];
}

I have thought that it would take me a long time to fix. But in fact it took only 1.5 hours to fix. All the solution is found in the Apple's help document. Not too bad !

Possible issue of contact book in iOS 9 is included in http://lifewithdotnet.blogspot.se/2015/09/welcome-to-ios9-issues-collection.html

Change status bar color in iOS app

2015-01-08T12:44:00.001-08:00

Some apps may have dark background which makes the statusbar not very clear. There are some steps to achieve a white statusbar content (including text, mobile signal strength icon and wifi icons) in an app with dark background.

I have found some answers on http://stackoverflow.com/questions/17678881/how-to-change-status-bar-text-color-in-ios-7 . The following is what works for my iPhone 4s with iOS7.1 and iPhone6 simulators.

Steps:

On you project plist file:

Status bar style: transparent black style
View controller-based status bar appearance: NO
Status bar is initially hidden: NO

Add this line in didFinishLaunchingWithOptions

[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];

Then it should work :)