Android对屏幕下方经常使用的四个按键消息处理是不一致的：

1、搜索按键的消息在onKeyDown或者onKeyUp中接收；

2、菜单按键的消息在onCreateOptionsMenu、onKeyDown或onKeyUp方法中接收；

3、返回按键的消息能够在onBackPressed、onKeyDown或onKeyUp方法中接收。

@Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
    	switch( keyCode ){
    	case KeyEvent.KEYCODE_BACK:{
    		
    	}
    	break;
    	case KeyEvent.KEYCODE_MENU:{
    		
    	}
    	break;
    	case KeyEvent.KEYCODE_SEARCH:{
    		
    	}
    	break;
    	default:{
    		
    	}
    	break;
    	}
    	return super.onKeyDown(keyCode, event);
    }
    
    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
    	switch( keyCode ){
    	case KeyEvent.KEYCODE_BACK:{
    		
    	}
    	break;
    	case KeyEvent.KEYCODE_MENU:{
    		
    	}
    	break;
    	case KeyEvent.KEYCODE_SEARCH:{
    		
    	}
    	break;
    	default:{
    		
    	}
    	break;
    	}
    	return super.onKeyUp(keyCode, event);
    }
    
    @Override
	public boolean onCreateOptionsMenu(Menu menu) {
		return true;
	}
    
    @Override
    public void onBackPressed() {
    	super.onBackPressed();
    }

注：网上提供了各种各样监听Home按键消息的方法，但仅仅有这个比較好使。

    但办法总是有的，在每次点击Home按键时都会发出一个action为Intent.ACTION_CLOSE_SYSTEM_DIALOGS的广播，它是关闭系统Dialog的广播，我们能够通过注冊它来监听Home按键消息。我自己定义了一个home按键监听工具类。代码例如以下。使用说明參见类名上方的使用说明：

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

/**
 * Home按键监听类
 * 使用说明：
 * 1、初始化HomeListen
 * HomeListen homeListen = new HomeListen( this );
 * homeListen.setOnHomeBtnPressListener( new setOnHomeBtnPressListener(){
 * 		@Override
 * 		public void onHomeBtnPress( ){
 * 			// 按下Home按键回调
 * 		}
 * 		
 * 		@Override
 * 		public void onHomeBtnLongPress( ){
 * 			// 长按Home按键回调
 * 		}
 * });
 * 
 * 2、在onResume方法中启动HomeListen广播：
 * homeListen.start();
 * 
 * 3、在onPause方法中停止HomeListen广播：
 * homeListen.stop( );
 * */
public class HomeListen {
	public HomeListen(Context context) {
		mContext = context;
		mHomeBtnReceiver = new HomeBtnReceiver( );
		mHomeBtnIntentFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
	}
	
	public void setOnHomeBtnPressListener( OnHomeBtnPressLitener onHomeBtnPressListener ){
		mOnHomeBtnPressListener = onHomeBtnPressListener;
	}
	
	public void start( ){
		mContext.registerReceiver( mHomeBtnReceiver, mHomeBtnIntentFilter );
	}
	
	public void stop( ){
		mContext.unregisterReceiver( mHomeBtnReceiver );
	}
	
	class HomeBtnReceiver extends BroadcastReceiver{
		@Override
		public void onReceive(Context context, Intent intent) {
			receive( context, intent );
		}
	}
	
	private void receive(Context context, Intent intent){
		String action = intent.getAction();
		if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {
			String reason = intent.getStringExtra( "reason" );
			if (reason != null) {
				if( null != mOnHomeBtnPressListener ){
					if( reason.equals( "homekey" ) ){
						// 按Home按键
						mOnHomeBtnPressListener.onHomeBtnPress( );
					}else if( reason.equals( "recentapps" ) ){
						// 长按Home按键
						mOnHomeBtnPressListener.onHomeBtnLongPress( );
					}
				}
			}
		}
	}
	
	public interface OnHomeBtnPressLitener{
		public void onHomeBtnPress( );
		public void onHomeBtnLongPress( );
	}
	
	private Context mContext = null;
	private IntentFilter mHomeBtnIntentFilter = null;
	private OnHomeBtnPressLitener mOnHomeBtnPressListener = null;
	private HomeBtnReceiver mHomeBtnReceiver = null;
}

public class HomeListenActivity extends Activity {
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_home_listen_layout);  
        initHomeListen( );
    }
    
    @Override
    protected void onResume( ) {
    	super.onResume();
    	mHomeListen.start( );
    }
  
    @Override  
    protected void onPause() {  
        super.onPause();
        mHomeListen.stop( );
    }
    
    private void initHomeListen( ){
    	mHomeListen = new HomeListen( this );
    	mHomeListen.setOnHomeBtnPressListener( new OnHomeBtnPressLitener( ) {
			@Override
			public void onHomeBtnPress() {
				showToast( "按下Home按键！" );
			}
			
			@Override
			public void onHomeBtnLongPress() {
				showToast( "长按Home按键！" );
			}
		});
    }
    
    private void showToast( String toastInfoStr ){
    	Toast.makeText( this, toastInfoStr, Toast.LENGTH_LONG ).show( );
    }

    private HomeListen mHomeListen = null;
}