Android之Home键监听封装

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。
    }
}