如何检测和计数，当活动进入从背景到前景 [英] How to detect and count when activity goes from background to foreground

问题描述

我想检测和计数，当活动去从背景到前台（活动时可见，加大计）。我试图用标志的onPause（）和 onResume（）是这样的：

I want to detect and count when Activity goes from background to foreground (when activity is visible, increase count).I tried to use flag in onPause() and onResume() like this:

void onPause(){
    flag = true;
}

void onResume(){
if(flag){
 //save to shared reference.  
   saveCount(getCount(count) + 1);
 flag = false;
}

}

它的工作原理，当用户preSS 家居键，将重新启动应用程序，但是当我转移活动然后回到过去，它仍然增加了计数，因为它调用的onPause（）。如何prevent是什么？或者，反正是有这个数？

It works when user press home key and relaunches the app, but when I transfer Activity then goes back, it still increases the count, because it calls onPause(). How to prevent that? Or is there anyway to count this?

推荐答案

使用此方法来检查wheter应用程序被带到后台：

Use this method to check wheter app is brought to background:

private boolean isApplicationBroughtToBackground(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;
}

它需要GET_TASKS权限：

It requires the GET_TASKS permission:

<uses-permission android:name="android.permission.GET_TASKS" />

这篇关于如何检测和计数，当活动进入从背景到前景的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！