在做一个程序的时候,需要时刻保持某一服务是启动的,因此想到了通过监听屏幕SCREEN_ON和SCREEN_OFF这两个action。奇怪的是,这两个action只能通过代码的形式注册,才能被监听到,使用AndroidManifest.xml 完全监听不到。查了一下,发现这是PowerManager那边在发这个广播的时候,做了限制,限制只能有register到代码中的receiver才能接收。
代码如下:
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.转