Android中对menu、home、back键的监听

 Android中对menu、home、back键的监听，通过KeyEvent中的常量值来判断用户点击了哪个按钮。

其中对home键的监听需先在manifest文件中添加

<uses-permission android:name="android.permission.DISABLE_KEYGUARD"/> 

这一权限，并且在程序中复写onAttachedToWindow()方法，以便解除系统对home键的守护。

具体详见下面的例子：  

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.WindowManager;
import android.widget.Toast;

public class TestAndroidActivity extends Activity {
    /** Called when the activity is first created. */
 private final String TAG = "TestAndroidActivity";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    @Override
    public void onAttachedToWindow() {
     super.onAttachedToWindow();
     this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);      
    }
 @Override
 public boolean onKeyDown(int keyCode, KeyEvent event) {
  switch(keyCode){
     case KeyEvent.KEYCODE_MENU:
      Log.d(TAG, "KeyEvent.KEYCODE_MENU");
      Toast.makeText(this, "KeyEvent.KEYCODE_MENU", Toast.LENGTH_LONG);
     break;
     case KeyEvent.KEYCODE_HOME:
      Log.d(TAG, "KeyEvent.KEYCODE_HOME");
      finish();
      Toast.makeText(this, "KeyEvent.KEYCODE_HOME", Toast.LENGTH_LONG);
     break;
     case KeyEvent.KEYCODE_BACK:
      Log.d(TAG, "KeyEvent.KEYCODE_BACK");
      Toast.makeText(this, "KeyEvent.KEYCODE_BACK", Toast.LENGTH_LONG);
     break;
     default:
      Log.d(TAG, "没有匹配的");

         Toast.makeText(this, "KeyEvent.没有匹配的", Toast.LENGTH_LONG);
  }
  return super.onKeyDown(keyCode, event);
 }
    
}

最后在manifest文件中添加<uses-permission android:name="android.permission.DISABLE_KEYGUARD"/>