Android监听程序进入后台，或者恢复到前台

1、通过RunningTaskInfo类判断（需要额外权限）：
/**
*判断当前应用程序处于前台还是后台
*/
public static boolean isApplicationBroughtToBackground(final Context context) {
ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<RunningTaskInfo> tasks = am.getRunningTasks(1);
if (!tasks.isEmpty()) {
ComponentName topActivity = tasks.get(0).topActivity;
if (!topActivity.getPackageName().equals(context.getPackageName())) {
return true;
}
}
return false;
}
需要在AndroidMenitfest.xml文件中添加以下权限
<uses-permission Android:name=”android.permission.GET_TASKS” />
2.基本思路：让app中所有的activity继承与一个公共的activity（例如：BaseActivity），然后在BaseActivity的onStop()中判断当前程序是否处于后台
/**
* 文件名：BaseActivity.Java
* 版本号：
* 日期：2012-6-20
* 创建人：
* Copyright wadata 版权所有
* 变更：
*/
package com.wadata.mobilefollowup.view.base;
import java.util.List;
import android.app.Activity;
import android.app.ActivityManager;
import android.app.ActivityManager.RunningAppProcessInfo;
import android.content.Context;
/**
* 名称：BaseActivity
* 描述：
* 创建人：
* 日期：2012-6-20 下午5:53:35
* 变更：
*/
public class BaseActivity extends Activity {
@Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
if (!isAppOnForeground()) {
//app 进入后台
//全局变量isActive = false 记录当前已经进入后台
}
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
//if (!isActive) {
//app 从后台唤醒，进入前台
//isActive = true;
//}
}
/**
* 程序是否在前台运行
*
* @return
*/
public boolean isAppOnForeground() {
// Returns a list of application processes that are running on the
// device
ActivityManager activityManager = (ActivityManager) getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
String packageName = getApplicationContext().getPackageName();
List<RunningAppProcessInfo> appProcesses = activityManager
.getRunningAppProcesses();
if (appProcesses == null)
return false;
for (RunningAppProcessInfo appProcess : appProcesses) {
// The name of the process that this object is associated with.
if (appProcess.processName.equals(packageName)
&& appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
return true;
}
}
return false;
}
}