Android上的覆蓋屏幕

Question

如何將視圖/圖像添加到我的主屏幕？

最好的例子是Facebook的信使：如果你長時間在聊天項目，你可以選擇「彈出作弊頭」，然後你有一個小按鈕覆蓋你的屏幕。

也有類似屏幕保護程序的應用程序，來自破損顯示屏的圖像覆蓋手機中的所有內容。

我已經搜索過它，但我不知道它叫什麼。

我希望你們能夠理解我的英語。

Answer 1

答案是SYSTEM_ALERT_WINDOW，這讓你有能力在android中繪製任何東西，同樣的功能，facebook用於繪製它的聊天頭。

http://developer.android.com/reference/android/Manifest.permission.html#SYSTEM_ALERT_WINDOW

示例代碼：

private WindowManager windowManager; 
    private ImageView imageView; 
    // Get window manager reference 

    windowManager = (WindowManager) getSystemService(WINDOW_SERVICE); 

    imageView= new ImageView(YOUR_CONTEXT_HERE); 
    imageView.setImageResource(R.drawable.android_head); 

    // Setup layout parameter 
    WindowManager.LayoutParams params = new WindowManager.LayoutParams(
     WindowManager.LayoutParams.WRAP_CONTENT, 
     WindowManager.LayoutParams.WRAP_CONTENT, 
     WindowManager.LayoutParams.TYPE_PHONE, 
     WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE, 
     PixelFormat.TRANSLUCENT); 

    params.gravity = Gravity.TOP | Gravity.LEFT; // Orientation 
    params.x = 100; // where you want to draw this, coordinates 
    params.y = 100; 
    // At it to window manager for display, it will be printed over any thing 
    windowManager.addView(chatHead, params); 


    // Make sure to remove it when you are done, else it will stick there until you reboot 
    // Do keep track of same reference of view you added, don't mess with that 
    windowManager.removeView(imageView);