當我的應用程序處於前臺時，是否可以截取屏幕截圖事件

Question

當我的應用程序處於前臺時，是否可以攔截截屏事件（或爲其創建偵聽程序）？我想通過vol down + power key拍攝屏幕截圖時執行一些自己的代碼。

Answer 1

不，抱歉，您無法控制屏幕截圖。如果你的目的是防止您的應用已採取（例如安全原因）的截圖，使用FLAG_SECURE：

public class FlagSecureTestActivity extends Activity { 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    getWindow().setFlags(LayoutParams.FLAG_SECURE, 
         LayoutParams.FLAG_SECURE); 

    setContentView(R.layout.main); 
    } 
} 

Answer 2

做這個任務的方法是在截圖目錄中添加一個文件觀察者。在下面編寫示例代碼以觀察文件路徑 截圖文件觀察者 package com.example.main;

import android.os.Environment; 
import android.os.FileObserver; 
import android.util.Log; 

public class ScreenshotObserver extends FileObserver { 
     private static final String PATH = Environment.getExternalStorageDirectory().toString() + "/Pictures/Screenshots"; 
     private static final String TAG = "ScreenshotObserver"; 

     private ScreenshotListener listener; 
     private String mLastTakenPath; 

     ScreenshotObserver(ScreenshotListener listener) { 
      super(PATH); 
      this.listener = listener; 
      Log.d(TAG, PATH); 
     } 

     @Override 
     public void onEvent(int event, String path) { 
      Log.d(TAG, String.format("Detected new file added %s", path)); 
      if (path==null || event != FileObserver.CLOSE_WRITE) 
       Log.d(TAG, "Don't care."); 
      else if (mLastTakenPath!=null && path.equalsIgnoreCase(mLastTakenPath)) 
       Log.d(TAG, "This event has been observed before."); 
      else { 
       mLastTakenPath = path; 
       listener.onScreenshotTaken(path); 
       Log.d(TAG, "Send event to listener."); 
      } 
     } 

     public void start() { 
      super.startWatching(); 
      Log.d(TAG, "Start Watching."); 
     } 

     public void stop() { 
      super.stopWatching(); 
      Log.d(TAG, "Stop Watching."); 
     } 
} 

活動實現文件觀察者

import android.app.Activity; 
import android.os.Bundle; 
import android.widget.TextView; 


public class MainActivity extends Activity implements ScreenshotListener{ 
    private ScreenshotObserver obs; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     obs = new ScreenshotObserver(this); 
     obs.start(); 
     setContentView(R.layout.activity_main); 
    } 

    @Override 
    public void onScreenshotTaken(String path) { 
     TextView t = (TextView)findViewById(R.id.monText); 
     t.setText("Screenshot taken ! " + path); 
    } 
}