学步园

众所周知，我们监听返回键事件，无法是下面两个方法：

@Override
	public void onBackPressed() {
		//do something
		//super.onBackPressed();
	}
	
	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		if(keyCode == KeyEvent.KEYCODE_BACK){
			//do something
		}
		return super.onKeyDown(keyCode, event);
	}

于是乎，我们理所当然的想到，监听Home键的方法是：if(keyCode == KeyEvent.KEYCODE_HOME)。但实际上，这样是行不通的，因为此时home键的消息在framework层就已经被拦截，所以，我们在应用中通过此方法是无法监听到Home键的消息的。那么我们如何捕获Home键事件，并作出相应处理呢？其实系统还是给我们发出广播的，下面，就跟大家分享一下，封装好了的监听Home键的方法：

HomeWatcher类：

/**
 * Home键监听封装
 * 
 * @author way
 * 
 */
public class HomeWatcher {

	static final String TAG = "HomeWatcher";
	private Context mContext;
	private IntentFilter mFilter;
	private OnHomePressedListener mListener;
	private InnerRecevier mRecevier;

	// 回调接口
	public interface OnHomePressedListener {
		public void onHomePressed();

		public void onHomeLongPressed();
	}

	public HomeWatcher(Context context) {
		mContext = context;
		mFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
	}

	/**
	 * 设置监听
	 * 
	 * @param listener
	 */
	public void setOnHomePressedListener(OnHomePressedListener listener) {
		mListener = listener;
		mRecevier = new InnerRecevier();
	}

	/**
	 * 开始监听，注册广播
	 */
	public void startWatch() {
		if (mRecevier != null) {
			mContext.registerReceiver(mRecevier, mFilter);
		}
	}

	/**
	 * 停止监听，注销广播
	 */
	public void stopWatch() {
		if (mRecevier != null) {
			mContext.unregisterReceiver(mRecevier);
		}
	}

	/**
	 * 广播接收者
	 */
	class InnerRecevier extends BroadcastReceiver {
		final String SYSTEM_DIALOG_REASON_KEY = "reason";
		final String SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS = "globalactions";
		final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps";
		final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey";

		@Override
		public void onReceive(Context context, Intent intent) {
			String action = intent.getAction();
			if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {
				String reason = intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
				if (reason != null) {
					Log.e(TAG, "action:" + action + ",reason:" + reason);
					if (mListener != null) {
						if (reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)) {
							// 短按home键
							mListener.onHomePressed();
						} else if (reason
								.equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) {
							// 长按home键
							mListener.onHomeLongPressed();
						}
					}
				}
			}
		}
	}
}

接下来，我们需要在应用中开启监听，下面是以在Activity中的应用为例：

/**
 * 应用HomeWatcher小例
 * 
 * @author way
 * 
 */
public class MainActivity extends Activity {
	private static final String TAG = "MainActivity";
	private HomeWatcher mHomeWatcher;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		mHomeWatcher = new HomeWatcher(this);
		mHomeWatcher.setOnHomePressedListener(new OnHomePressedListener() {
			@Override
			public void onHomePressed() {
				Log.e(TAG, "onHomePressed");
			}

			@Override
			public void onHomeLongPressed() {
				Log.e(TAG, "onHomeLongPressed");
			}
		});
		mHomeWatcher.startWatch();
	}

	@Override
	protected void onPause() {
		super.onPause();
		mHomeWatcher.stopWatch();// 在onPause中停止监听，不然会报错的。
	}
}