android琐碎笔记

1.得到屏幕的screen dimensions 
Display display = getWindowManager().getDefaultDisplay(); 
int width = display.getWidth();int height = display.getHeight(); 

2. 播放 gif图片在android 
@Override protected void onDraw(Canvas canvas) {           
canvas.drawColor(0xFFCCCCCC);                       
  Paint p = new Paint();            
  p.setAntiAlias(true);          
      
     canvas.drawBitmap(mBitmap4, 210, 170, null);            
     mDrawable.draw(canvas);            
     long now = android.os.SystemClock.uptimeMillis();           
      if (mMovieStart == 0) {   // first time                mMovieStart = now;            }            
      if (mMovie != null) {                
        int dur = mMovie.duration();                
           if (dur == 0) {                    
              dur = 1000;                }                
              int relTime = (int)((now - mMovieStart) % dur);                
              mMovie.setTime(relTime);              
                mMovie.draw(canvas, getWidth() - mMovie.width(),                          
                  getHeight() - mMovie.height());               
                   invalidate();            
                   }       
                    } 
http://developer.android.com/guide/samples/ApiDemos/src/com/example/android/apis/graphics/BitmapDecode.html
@Override 
                    protected void onDraw(Canvas canvas) { 
                        if(movie != null) { 
                                long now = android.os.SystemClock.uptimeMillis(); 
                                        int dur = Math.max(movie.duration(), 1); 
                                        // is it really animated?        
                                        int pos = (int)(now % dur);        
                                        movie.setTime(pos);        
                                        movie.draw(canvas, x, y); 
                                         invalidate();    
                                 }} 

4. 打开sd卡中的sqllite 
File dbfile = new File("/sdcard/mydb.sqlite" ); 
                                  SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(dbfile, null); 

5.得到手机的IMEI 
((TelephonyManager) getSystemService=(Context.TELEPHONY_SERVICE)).getDeviceId(); 

6. 不让程序 生成一个appliation 去掉 
<category android:name="android.intent.category.LAUNCHER" /> 
当然你的让你的程序 被引导启动 

7.使用appliation 的id 可以获得不同appliation的数据： 
android:sharedUserId="string" 在主xml中添加上面一句话，然后签名也要一样 两个app的id也要设置成一样 如都是string 那么这两个程序就可以相互访问彼此的数据，也可以在同一个process中了 
8.判断相机设备存在不 
private android.hardware.Camera mCameraDevice; 
try {  
    mCameraDevice = android.hardware.Camera.open();} 
catch (RuntimeException e) {  Log.e(TAG, "fail to connect Camera", e); 

9使listView 透明 
android:background="#00000000" 
android:cacheColorHint="#00000000" 
或者 
android:background="@android:color/transparent" 

•The background android screen image should be visible. 
屏幕的背景图像可以看见 
manifest file 添加attribute 到 activity. 
android:theme="@android:style/Theme.Dialog"