Android 监听屏幕锁屏&用户解锁

在做视频播放器的时候，遇到一个问题，在用户播放视频然后锁屏之后，视频播放器仍然在继续播放，遇到类似手机系统状态改变的问题的时候,首先想到了广播，下面做个总结：

public class ScreenListener {
    private Context mContext;
    private ScreenBroadcastReceiver mScreenReceiver;
    private ScreenStateListener mScreenStateListener;

    public ScreenListener(Context context) {
        mContext = context;
        mScreenReceiver = new ScreenBroadcastReceiver();
    }

    /**
     * screen状态广播接收者
     */
    private class ScreenBroadcastReceiver extends BroadcastReceiver {
        private String action = null;

        @Override
        public void onReceive(Context context, Intent intent) {
            action = intent.getAction();
            if (Intent.ACTION_SCREEN_ON.equals(action)) { // 开屏
                mScreenStateListener.onScreenOn();
            } else if (Intent.ACTION_SCREEN_OFF.equals(action)) { // 锁屏
                mScreenStateListener.onScreenOff();
            } else if (Intent.ACTION_USER_PRESENT.equals(action)) { // 解锁
                mScreenStateListener.onUserPresent();
            }
        }
    }

    /**
     * 开始监听screen状态
     * 
     * @param listener
     */
    public void begin(ScreenStateListener listener) {
        mScreenStateListener = listener;
        registerListener();
        getScreenState();
    }

    /**
     * 获取screen状态
     */
    private void getScreenState() {
        PowerManager manager = (PowerManager) mContext
                .getSystemService(Context.POWER_SERVICE);
        if (manager.isScreenOn()) {
            if (mScreenStateListener != null) {
                mScreenStateListener.onScreenOn();
            }
        } else {
            if (mScreenStateListener != null) {
                mScreenStateListener.onScreenOff();
            }
        }
    }

    /**
     * 停止screen状态监听
     */
    public void unregisterListener() {
        mContext.unregisterReceiver(mScreenReceiver);
    }

    /**
     * 启动screen状态广播接收器
     */
    private void registerListener() {
        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_SCREEN_ON);
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        filter.addAction(Intent.ACTION_USER_PRESENT);
        mContext.registerReceiver(mScreenReceiver, filter);
    }

    public interface ScreenStateListener {// 返回给调用者屏幕状态信息
        public void onScreenOn();

        public void onScreenOff();

        public void onUserPresent();
    }
}

在上面的代码中,用到了动态注册广播,在需要监听屏幕状态的activity中,当不需要监听的时候,如activity finish的时候,使用unregisterListener解除广播监听; 

下面是在Activity中调用;

ScreenListener l = new ScreenListener(this);
        l.begin(new ScreenStateListener() {

            @Override
            public void onUserPresent() {
                Log.e("onUserPresent", "onUserPresent");
            }

            @Override
            public void onScreenOn() {
                Log.e("onScreenOn", "onScreenOn");
            }

            @Override
            public void onScreenOff() {
                Log.e("onScreenOff", "onScreenOff");
            }
        });

通过以上步骤即实现了对屏幕状态的监听.