Android如何获取到正在运行Activity的缩略图，RunningTaskInfo的thumbnail属性获取总是为空，求解

[size=medium][color=red]Android如何获取到正在运行Activity的缩略图，RunningTaskInfo的thumbnail属性获取总是为空，求解![/color][/size]

[code="java"]
public void getAppProcesses(){
taskPics = new ArrayList();
ActivityManager actManager = (ActivityManager)this.getSystemService(Activity.ACTIVITY_SERVICE);
List runningApp = actManager.getRunningTasks(10);
PackageManager pm = TaskDemActivity.this.getPackageManager();
for(RunningTaskInfo tempApp : runningApp){
String pkgName=tempApp.baseActivity.getPackageName();
if(tempApp.thumbnail == null){
taskPics.add(getResources().getDrawable(R.drawable.icon));
}else{
taskPics.add(new BitmapDrawable(tempApp.thumbnail));
}

        System.out.println("tempApp.thumbnail=="+tempApp.thumbnail);
   }

}

[/code]

[code="java"]http://www.bangchui.org/read.php?tid=12612&page=1[/code]

下面这个贴子来自于Android官方论坛：
[url]http://groups.google.com/group/android-developers/browse_thread/thread/279b81b47ce11bc1[/url]，里面有一句：[quote]This is not currently supported. We weren't using it anywhere in the UI on
the G1, so we turned it off to avoid wasting time/space. [/quote]
和
[quote]There is just an if statement in android.app.ActivityThread.java that has it
currently turned off. [/quote]

[code="java"] :? 还像得修改 framework了
[/code]

所以，你最好去查看一下 android.app.ActivityThread.java ，看你用的android版本中的这个类，是否仍然未实现这个特性。