Android 监控屏幕的开关

//屏幕监视类
public class ScreenObserver {
private static String TAG = "ScreenObserver";
private Context mContext;
private ScreenBroadcastReceiver mScreenReceiver;
private ScreenStateListener mScreenStateListener;
private static Method mReflectScreenState;

public ScreenObserver(Context context) {
mContext = context;
mScreenReceiver = new ScreenBroadcastReceiver();
try {
mReflectScreenState = PowerManager.class.getMethod("isScreenOn",
new Class[] {});
} catch (NoSuchMethodException nsme) {
Log.d(TAG, "API < 7," + nsme);
}
}

// 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)) {
mScreenStateListener.onScreenOn();
} else if (Intent.ACTION_SCREEN_OFF.equals(action)) {
mScreenStateListener.onScreenOff();
}
}
}

// 请求screen状态更新
public void requestScreenStateUpdate(ScreenStateListener listener) {
mScreenStateListener = listener;
startScreenBroadcastReceiver();

firstGetScreenState();
}

// 第一次请求screen状态
private void firstGetScreenState() {
PowerManager manager = (PowerManager) mContext
.getSystemService(Activity.POWER_SERVICE);
if (isScreenOn(manager)) {
if (mScreenStateListener != null) {
mScreenStateListener.onScreenOn();
}
} else {
if (mScreenStateListener != null) {
mScreenStateListener.onScreenOff();
}
}
}

// 停止screen状态更新
public void stopScreenStateUpdate() {
mContext.unregisterReceiver(mScreenReceiver);
}

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

// screen是否打开状态
private static boolean isScreenOn(PowerManager pm) {
boolean screenState;
try {
screenState = (Boolean) mReflectScreenState.invoke(pm);
} catch (Exception e) {
screenState = false;
}
return screenState;
}

public interface ScreenStateListener {
public void onScreenOn();

public void onScreenOff();
}
}



//调用的例子
public class MainActivity extends Activity {

private ScreenObserver mScreenObserver;
private WifiManager wifiManager;

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

wifiManager = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);

mScreenObserver = new ScreenObserver(this);
mScreenObserver.requestScreenStateUpdate(new ScreenStateListener() {
@Override
public void onScreenOn() {
doSomethingOnScreenOn();
}

@Override
public void onScreenOff() {
doSomethingOnScreenOff();
}
});
}

private void doSomethingOnScreenOn() {
System.out.println("Screen is on");
wifiManager.setWifiEnabled(true);

}

private void doSomethingOnScreenOff() {
System.out.println("Screen is off");
wifiManager.setWifiEnabled(false);
}

@Override
protected void onDestroy() {
super.onDestroy();
// 停止监听screen状态
mScreenObserver.stopScreenStateUpdate();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}

}