Android应用程序自动进入前台

Question

在我的FirstActivity应用程序中，异步任务结束时调用了Asynctask，secondactivity将被打开

当应用程序在后台运行时，异步任务完成后运行asyntask时，应用程序自动进入前台，而无需任何用户交互

如何避免呢？

Answer 1

在android中，我们可以找到该应用位于前景或背景，如下所示：

ActivityManager activityManager = (ActivityManager) getApplicationContext()
.getSystemService(Activity.ACTIVITY_SERVICE);
String className = activityManager.getRunningTasks(1).get(0).topActivity
.getClassName();

if (className.equals("your activity class name with package")) {
//ToDO
}

Answer 2

在开始第二个活动之前，请使用以下方法检查应用程序是否处于前台：

public static boolean isApplicationSentToBackground(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;
}

Answer 3

检查是否打开了任何活动。

    /***
     * Checking Whether any Activity of Application is running or not
     * @param context
     * @return
     */
    public boolean isForeground(Context context) {

        // Get the Activity Manager
        ActivityManager manager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

        // Get a list of running tasks, we are only interested in the last one, 
        // the top most so we give a 1 as parameter so we only get the topmost.
        List< ActivityManager.RunningTaskInfo > task = manager.getRunningTasks(1); 

        // Get the info we need for comparison.
        ComponentName componentInfo = task.get(0).topActivity;

        // Check if it matches our package name.
        if(componentInfo.getPackageName().equals(context.getPackageName())) 
            return true;

        // If not then our app is not on the foreground.
        return false;
    }

像这样使用：

if(isForeground(context)) {
    //Nothing to do
} else {

    /**
          You can do here what you want to do
      **/

}