(XCode) How to setup a bracket / brace macro in XCode

Before i used XCode and learned Objective-C, i never thought the bracket is a horrible symbol, there is a solution of creating text macro to insert bracket / brace:

1. Open ObjectiveC.xctxtmacro with an text editor, you can find this file with this path:

/Developer/Applications/Xcode.app/Contents/PlugIns/TextMacros.xctxtmacro/Contents/Resources/ObjectiveC.xctxtmacro 

2.Add follow code in the file:

{
Identifier = objc.bracket;
BasedOn = objc;
IsMenuItem = YES;
Name = "Bracket Expression";
TextString = "[<#!expression!#>]";
CompletionPrefix = bra;
},

This scope create a text macro "bra" to insert "[<#!expression!#>]", you need to type bra in your code and presse "esc" button, there is a window shows "Bracket Expression", press enter "[<#!expression!#>]" will be inserted.

You can create a similar macro for Brace, here is an example:

{
Identifier = objc.brace;
BasedOn = objc;
IsMenuItem = YES;
Name = "Brace Expression";
TextString = "{<#!expression!#>}";
CompletionPrefix = bra;
},

Here you have a same text macro "bra" to choose bracket or brace.

Update: In the XCode 3.2 which is released for Snow Leopard, the above lines wouldn't work until add this line in each section:

OnlyAtBOL = YES;

(Android) First application released

I just released my first application on the Android Market. It is Voice Dictionary which is a very useful tool for translating words or phrases between 17 different languages (Chinese, English, French, German, Italian, Spanish etc), the Voice Dictionary also supports Text-To-Speech to give you a full experience of pronunciation.

It uses Google Translate service API and eyes-free TTS engine for Android.

Here is a web version Android Market which contains this app's information.

(Android) How to write your code with a good style

I saw an excellent article in Android Code Source site, it is a Code Style Guide, which is Google Android team asks their developer to respect. Writing code with a good style helps others to read your code, and developer should have a good habit of writing code too.

Code Style Guide

(Objective-C) How to sort an array

Here is an example to sort an array:

- (NSArray *) sortArray:(NSArray *)array :(BOOL)inAscending {
  if (inAscending) {
      return [array sortedArrayUsingSelector:@selector(compare:)];
  }
  else {
      NSArray *ascendArray = [array sortedArrayUsingSelector:@selector(compare:)];
      return [[ascendArray reverseObjectEnumerator] allObjects];
  }
}

(Android) How to use horizontal scrolling in a ListView

ListView is a widget which shows items in a vertically scrolling list. I figure out a solution to add horizontal scrolling in a ListView. Here is my new object called MyListView, i used OnGestureListener's onScroll methods to manage the horizontal scrolling.

public class MyListView extends LinearLayout implements OnGestureListener {
 private GestureDetector mGestureDetector;
 private ListView mListView;

 public MyListView(Context context) {
     super(context);
     mGestureDetector = new GestureDetector(this);
     mGestureDetector.setIsLongpressEnabled(false);
     mListView = new ListView(context);
     mListView.setItemsCanFocus(true);
     String[] items = createStrins();
     mListView.setAdapter(new ArrayAdapter(context, android.R.layout.simple_list_item_single_choice, items));
     this.addView(mListView, new LinearLayout.LayoutParams(350, LayoutParams.FILL_PARENT));
 }

 @Override
 public boolean onDown(MotionEvent arg0) {
     return false;
 }

 @Override
 public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
     return true;
 }

 @Override
 public void onLongPress(MotionEvent e) {
     //empty
 }

 @Override
 public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
     int scrollWidth = mListView.getWidth() - this.getWidth();
     if ((this.getScrollX() >= 0) && (this.getScrollX() <= scrollWidth) && (scrollWidth > 0)) {
         int moveX = (int)distanceX;
         if (((moveX + this.getScrollX()) >= 0) && ((Math.abs(moveX) + Math.abs(this.getScrollX())) <= scrollWidth)) {
             this.scrollBy(moveX, 0);
          }
         else {
             if (distanceX >= 0) {
                 this.scrollBy(scrollWidth - Math.max(Math.abs(moveX), Math.abs(this.getScrollX())), 0);
             }
             else {
                 this.scrollBy(-Math.min(Math.abs(moveX), Math.abs(this.getScrollX())), 0);
             }
         }
     }
     return true;
 }

 @Override
 public void onShowPress(MotionEvent e) {
     //empty
 }

 @Override
 public boolean onSingleTapUp(MotionEvent e) {
     return false;
 }

 @Override
 public boolean dispatchTouchEvent(MotionEvent ev){
     mGestureDetector.onTouchEvent(ev);
     return true;
 }

 private String[] createStrins() {
     return new String[] {
             "Abbaye de Belloc", "Abbaye du Mont des Cats", "Abertam", "Abondance"};
 }
}

(iPhone) How to localize your application

iPhone 3G embeds several language setting, it is pretty cool to write an application which has multi language support. Here are 2 solutions we could use to set an UIButton bt's title:

First:
- Find the device default language

  NSUserDefaults* defs = [NSUserDefaults standardUserDefaults];
  NSArray* languages = [defs objectForKey:@"AppleLanguages"];
  NSString* preferredLang = [languages objectAtIndex:0];

preferredLang returns the default language, it looks like: "en" for English, "fr" for French, "zh-Hans" for Chinese Simp, "zh-Hant" for Chinese Trad etc.

- Set up the text by different language

if ([preferredLang isEqualToString:@"en"]) {
  [bt setTitle:@"Hello" forState:UIControlStateNormal];
  }
else if ([preferredLang isEqualToString:@"fr"]) {
  [bt setTitle:@"Bonjour" forState:UIControlStateNormal];
}
.......
else if ([preferredLang isEqualToString:@"zh-Hans"]) {
  [bt setTitle:@"你好" forState:UIControlStateNormal];
}

Second:
- Create a strings file for your project (Add-New File-Strings File), Localizable.strings is a default strings file name, of course you can use the other names

- Make File Localizable: "Get Info" your strings file and click "Make File Localizable" on the left-bottom. You will see "English" shows on the Localizations list, and you can add the other languages by clicking "Add Localization". There are only 4 languages on the default list "English; French, Japnese and German". For the chinese, you should enter "zh_CN" for Chinese Simp and "zh_TW" for Chinese Trad, be careful it is different compare the first solution. After you have done this, there are several files under your strings file.

- Add the keys and values in the languages files. The format is:
in English
"hello" = "Hello !";

in French
"hello" = "Bonjour !";
etc.

Use the same keys for every language and just change the values. The iPhone will detect its language setting to load the right language file.

- Get the right text. If your strings file's name is Localizable, use NSLocalizedString(@"hello", nil) to get the value of "hello", if you use the other name, you should use NSLocalizedStringFromTable(@"hello", @"File name', nil) to return the text.

So the set bt's title, there is only one line of code:

[bt setTitle:NSLocalizedString(@"hello", nil) forState:UIControlStateNormal];

(Android) How to detect the rotation of screen

When the orientation of screen changed (portrait to landscape or reciprocate action), the current Activity will be paused->stopped->destroyed and then created->started->resumed with the new configuration (such as language changed, orientation changed..). It means we can detect the orientation on the OnCreate method, to get the current orientation, here is an example:

       if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
           Log.i("info", "landscape");
       }
       else if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
           Log.i("info", "portrait");
       }

So you can load the diffrent layout xml file to change your UI or change the layout parameter directly in the code.