安卓异步任务 : async-task for each viewpager fragment

Question

我有 viewpager 和 FragmentStatePagerAdapter。而我在Fragment中使用了AsyncTask，因为Fragment中有计算过程。这些 fragment 将从 FragmentStatePagerAdapter 加载。这是 fragment 中的快照代码..

public void refreshView() {
        if(asynTask == null) {
            asynTask = new SetupTableTask();
        }
        asynTask.execute();
    }

    private class SetupTableTask extends AsyncTask<Void, Void, Void> {

        @Override
        protected Void doInBackground(Void... arg0) {
            setupInitialValue();
            dashboradView.removeAllViews();
            setupTableRow();
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            progressDialog.dismiss();
        }

        @Override
        protected void onPreExecute() {
            progressDialog = ProgressDialog.show(getActivity(), "Dashboard",
                    " Loading...", true, false);
        }
    }

问题是当我快速滑动 4 或 5 页时。我得到了这个异常(exception)。

08-07 10:48:36.366: E/AndroidRuntime(5702): FATAL EXCEPTION: AsyncTask #2
08-07 10:48:36.366: E/AndroidRuntime(5702): java.lang.RuntimeException: An error occured while executing doInBackground()
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.os.AsyncTask$3.done(AsyncTask.java:299)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at java.lang.Thread.run(Thread.java:856)
08-07 10:48:36.366: E/AndroidRuntime(5702): Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:4607)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:835)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.view.View.requestLayout(View.java:15129)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.view.View.requestLayout(View.java:15129)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.view.View.requestLayout(View.java:15129)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.view.View.requestLayout(View.java:15129)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.widget.RelativeLayout.requestLayout(RelativeLayout.java:292)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.view.View.requestLayout(View.java:15129)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.view.View.requestLayout(View.java:15129)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.view.View.requestLayout(View.java:15129)
08-07 10:48:36.366: E/AndroidRuntime(5702):     at android.widget.RelativeLayout.requestLayout(RelativeLayout.java:292)

我想知道我可以在 ViewPager 的 fragment 中使用 AsyncTask 吗？有什么想法可以克服这个异常(exception)吗？我已经尝试过 Handler。我得到了与 CalledFromWrongThreadException 相同的异常。

谢谢

Answer 1

你不能在 AsyncTask doInBackground 中绑定(bind)或删除任何类型的 View

  dashboradView.removeAllViews();

将其从 doInBackground 中移除并放入 onPostExecute 在这里你可以绑定(bind)你的 View