Although there are many types of "windows" in Android system, only two types are often used: one is managed by system process, which is called "system window"; the other is generated by application program, which is used to display UI interface. If you are familiar with window manager service (WMS), everything is very simple. It is a service responsible for the overall management of all windows, which has been in operation from the beginning to the end. The reason why WMS is involved is that it is the big Boss, and all window changes should be notified to it. Although WindowManager has no relationship with it, it is responsible for it, and all information will be transmitted back to WMS through a certain way. Well, it's out of the question. We're talking about WindowManager, which is an interface class. It can manage view s, including adding, updating and deleting.

1, WindowManager

1. Get WindowManager
   

   wManager = (WindowManager) getApplicationContext().getSystemService(
                   Context.WINDOW_SERVICE);

   This method can be used directly in both Activity and Service to obtain WindowManager. Its getSystemService returns a WindowManagerImpl object, which is an object that exists in the local process. The fact is that WindowManagerImpl inherits WindowManager, while WindowManger inherits ViewManager.

   
   
2. set up WindowManager.LayoutParams
   LayoutParams stores the properties of windows. With this variable, you can assign various properties to windows. You can also change its attribute value to perform various operations, such as dragging and stretching of the suspended window.
   The detailed property sheet is as follows:
   http://www.cnblogs.com/shitianzeng/articles/2814050.html
   
   
   
3. WindowManager operations
   (1) Window add

   public void addView(View view, ViewGroup.LayoutParams params);

   (2) Window update

   public void updateViewLayout(View view, ViewGroup.LayoutParams params);

   (3) Window delete

   public void removeView(View view);

   All three of the above methods exist in ViewManager.

   
   

2, Suspended window example
Example design: use service to open the suspension window, where there is a custom View, and click to eliminate the suspension window.

1. The first is Service, which is opened by Activity. Get WindowManager before configuring properties
   
   

   public class WindowService extends Service implements OnClickListener {
   
       private WindowManager wManager;// Window manager
       private WindowManager.LayoutParams mParams;// Properties of the window
       private MyView myView;
       private boolean flag = true;
   
       @Override
       public IBinder onBind(Intent intent) {
           // TODO Auto-generated method stub
           return null;
       }
   
       @Override
       public void onCreate() {
           // TODO Auto-generated method stub
           wManager = (WindowManager) getApplicationContext().getSystemService(
                   Context.WINDOW_SERVICE);
           mParams = new WindowManager.LayoutParams();
           mParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;// System prompt window
           mParams.format = PixelFormat.TRANSLUCENT;// Support transparency
           //mParams.format = PixelFormat.RGBA_8888;
           mParams.flags |= WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;// focus
           mParams.width = 490;//Width and height of window
           mParams.height = 160;
           mParams.x = 0;//Offset of window position
           mParams.y = 0;
           //mParams.alpha  =0.1f; / / transparency of window
           myView = new MyView(this);
           myView.setOnClickListener(this);
           super.onCreate();
       }
   
       @Override
       public int onStartCommand(Intent intent, int flags, int startId) {
           // TODO Auto-generated method stub
           if (flag) {
               flag = false;
               wManager.addView(myView, mParams);//Add window
           }
           return super.onStartCommand(intent, flags, startId);
       }
   
       @Override
       public void onDestroy() {
           // TODO Auto-generated method stub
           if (myView.getParent() != null)
               wManager.removeView(myView);//Remove window
           super.onDestroy();
       }
   
       @Override
       public void onClick(View v) {
           // TODO Auto-generated method stub
           if (v.equals(myView)) {
               flag = true;
               if (myView.getParent() != null)
                   wManager.removeView(myView);//Remove window
           }
       }
   
   }

   

    

   
   
2. A custom view
   A long time ago, I wrote the surfaceView, which includes two display animations of text and pictures
   
   

   

   @SuppressLint("WrongCall")
   public class MyView extends SurfaceView implements SurfaceHolder.Callback {
   
       private static int span = 5;
       private MyThread wtf;
       private Paint paint;
       int sleepSpan = 150; // Animation delay ms
       Bitmap logo_s, logo_l; // logo picture reference
       int width_s; // Picture size
       int height_s;
       float currentX_s; // Picture location
       float currentY_s;
       float currentX_l; // Picture location
       float currentY_l;
       private Rect src;
       private RectF dst;
       private int currentAlpha = 0;
   
       public MyView(Context context) {
           super(context);
   
           this.getHolder().addCallback(this);// Set the implementer of the life cycle callback interface
           paint = new Paint();// Create a brush
           paint.setAntiAlias(true);// Turn on antialiasing
       }
   
       @Override
       public void surfaceCreated(SurfaceHolder holder) {
           logo_s = BitmapFactory
                   .decodeResource(getResources(), R.drawable.logo_s);
           logo_l = BitmapFactory
                   .decodeResource(getResources(), R.drawable.logo_l);
           // TODO Auto-generated method stub
           width_s = logo_s.getWidth();
           height_s = logo_s.getHeight();
           src = new Rect(0, 0, 0, height_s);
           // Location of large pictures
           currentX_s = 5;
           currentY_s = 5;
           dst = new RectF(currentX_s, currentY_s, currentX_s, currentY_s
                   + height_s);
           currentX_l = currentX_s + width_s - logo_l.getWidth();
           // Location of small pictures
           currentY_l = currentY_s + height_s;
           currentAlpha = 0;
           wtf = new MyThread();
           wtf.start();
       }
   
       @Override
       public void surfaceChanged(SurfaceHolder holder, int format, int width,
               int height) {
           // TODO Auto-generated method stub
   
       }
   
       @Override
       public void surfaceDestroyed(SurfaceHolder holder) {
           // TODO Auto-generated method stub
   
       }
   
       @Override
       public void onDraw(Canvas canvas) {
           // TODO Auto-generated method stub
           // Draw black filled rectangle clear background
           super.onDraw(canvas);
           
           paint.setAlpha(120);// Set opacity to 255
           paint.setColor(Color.BLACK);// Set brush color
           canvas.drawColor(Color.BLACK);
           // Make a planar map
           if (logo_s == null || logo_l == null)
               return;
           src.right += span;
           dst.right += span;
           canvas.drawBitmap(logo_s, src, dst, paint);
           paint.setAlpha(currentAlpha);
           canvas.drawBitmap(logo_l, currentX_l, currentY_l, paint);
           // canvas.drawBitmap(bitmap, src, dst, paint);
           /*
            * Rect src = new Rect(x1, y2, cx1,cy1); Rect dst = new Rect(x2, y2,
            * cx2, cy2); The first rectangle is which section of the bitmap you want to intercept. The second rectangle is where you want it to appear on the screen.
            * The two rectangles can be different sizes, and will be stretched automatically when drawing.
            */
       }
   
       class MyThread extends Thread {
           public void run() {
               SurfaceHolder mholder = MyView.this.getHolder();// Get callback interface
               // Draw tatans
               try {
                   sleep(500);
               } catch (InterruptedException e1) {
                   // TODO Auto-generated catch block
                   e1.printStackTrace();
               }
               for (int i = 0; i <= width_s / span; i++) {
                   Canvas canvas = mholder.lockCanvas();// Get canvas
                   try {
                       synchronized (mholder) // synchronization
                       {
                           onDraw(canvas);// conduct
                       }
                       sleep(20);
                   } catch (Exception e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
                   } finally {
                       if (canvas != null) {
                           mholder.unlockCanvasAndPost(canvas);
                       }
                   }
   
               }
               // Draw Tiantan wisdom
               for (int i = 0; i <= 25; i++) {
                   currentAlpha = i * 10;
                   Canvas canvas = mholder.lockCanvas();// Get canvas
                   try {
                       synchronized (mholder) // synchronization
                       {
                           onDraw(canvas);// conduct
                       }
                       sleep(25);
                   } catch (Exception e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
                   } finally {
                       if (canvas != null) {
                           mholder.unlockCanvasAndPost(canvas);
                       }
                   }
   
               }
           }
       }
   
   }

   
   
   
   
3. In Activity, click to open service
   
   

   @Override
       public boolean onTouchEvent(MotionEvent event) {
           // TODO Auto-generated method stub
           Log.d("CPACM","onTouchEvent");
           Intent intent = new Intent();
           intent.setClass(this, WindowService.class);
           startService(intent);
           this.finish();
           return super.onTouchEvent(event);
       }

   
   
   
4. manifest.xml
   

   <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" /> <!-- use SYSTEM_ALERT_WINDOW Must be added when -->

    

   
   
5. design sketch
     
   

3, Conclusion
The deeper you learn, the more you discover you need to learn!

========================================

Author: cpacm
Source:( http://www.cnblogs.com/cpacm/p/4087690.html)