android 如何判断程序是否在前台运行

private boolean isTopActivity(String packageName) {

 

System.out.println("**********************top packageName:"

+ packageName);

ActivityManager activityManager = (ActivityManager) this

.getSystemService(Context.ACTIVITY_SERVICE);

 

List<RunningTaskInfo> tasksInfo = activityManager.getRunningTasks(1);

if (tasksInfo.size() > 0) {

System.out.println("*********************curr packageName:"

+ tasksInfo.get(0).topActivity.getPackageName());

// 应用程序位于堆栈的顶层

if (packageName.equals(tasksInfo.get(0).topActivity

.getPackageName())) {

return true;

}

}

return false;

 

}