监听Android屏幕是否锁屏

转载请注明出处，原文网址：http://blog.csdn.net/m_changgong/article/details/7608911作者：张燕广

实现方法：1）通过BroadcastReceiver接收广播Intent.ACTION_SCREEN_ON和Intent.ACTION_SCREEN_OFF可以判断屏幕状态是否锁屏，但是只有屏幕状态发生改变时才会发出广播；

2）如果要在屏幕状态发生改变之前就想获取屏幕状态，可以通过反射机制调用PowerManager的isScreenOn方法 。

具体实现，见代码：

实现Screen状态监听的类ScreenObserver，实现如下：

package com.isoft.screen;

import java.lang.reflect.Method;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.PowerManager;
import android.util.Log;

/**
*
* @author zhangyg
*
*/
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
* @author zhangyg
*
*/
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
* @param listener
*/
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
* @param pm
* @return
*/
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();
}
}

测试ScreenObserver功能的示例类ScreenObserverActivity，实现如下：

package com.isoft.screen;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

import com.isoft.screen.ScreenObserver.ScreenStateListener;

public class ScreenObserverActivity extends Activity {
private String TAG = "ScreenObserverActivity";
private ScreenObserver mScreenObserver;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

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

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

private void doSomethingOnScreenOn() {
Log.i(TAG, "Screen is on");
}

private void doSomethingOnScreenOff() {
Log.i(TAG, "Screen is off");
}

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

源码：点击下载源码