Question

我使用ViewGroup和自动生成的ViewPager遇到了一些问题。我想添加一个视图并删除一个视图，但每次我尝试它时都会收到错误：

    01-20 14:05:40.028: E/AndroidRuntime(3615): FATAL EXCEPTION: AsyncTask #1
    01-20 14:05:40.028: E/AndroidRuntime(3615): java.lang.RuntimeException: An error occured while executing doInBackground()
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.os.AsyncTask$3.done(AsyncTask.java:299)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at java.util.concurrent.FutureTask.run(FutureTask.java:239)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at java.lang.Thread.run(Thread.java:856)
    01-20 14:05:40.028: E/AndroidRuntime(3615): Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:4746)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:823)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.view.View.requestLayout(View.java:15468)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.view.View.requestLayout(View.java:15468)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.view.View.requestLayout(View.java:15468)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.view.View.requestLayout(View.java:15468)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.view.ViewGroup.removeView(ViewGroup.java:3524)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at de.tecfriends.vbtsplash2013.MainActivity$DummySectionFragment.Teilnehmer(MainActivity.java:219)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at de.tecfriends.vbtsplash2013.MainActivity$DummySectionFragment$1.onTaskCompleted(MainActivity.java:148)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at de.tecfriends.vbtsplash2013.BackgroundDownload.doInBackground(BackgroundDownload.java:38)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at de.tecfriends.vbtsplash2013.BackgroundDownload.doInBackground(BackgroundDownload.java:1)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at android.os.AsyncTask$2.call(AsyncTask.java:287)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     at java.util.concurrent.FutureTask.run(FutureTask.java:234)
    01-20 14:05:40.028: E/AndroidRuntime(3615):     ... 4 more

在班级onCreateView中，我设置了一个名为vGroup的公共ViewGroup。在所有数据处理结束时，我尝试vGroup.removeView(vGroup.findViewById(1));和vGroup.addView(modeList);但我收到上述错误。

如何才能到original Thread我可以添加和删除视图ViewGroup？

Answer 1

ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.表示您正在尝试从后台线程访问UI元素，后台线程是非UI线程。

只应从vGroup.removeView()或onPreExecute()调用

onPostExecute()，因为这两个函数在UI线程上运行。

private class MyAsyncTask extends AsyncTask<String, Void, String> {

      @Override
      protected String doInBackground(String... params) {
            .... // runs on background / non-UI thread
      }      

      @Override
      protected void onPostExecute(String result) {   
            ... // runs on UI thread            
      }

      @Override
      protected void onPreExecute() {
            ... // runs on UI thread      
      }

      @Override
      protected void onProgressUpdate(Void... values) {
      }
}

Documentation of AsyncTask

Answer 2

您正在从后台线程调用vGroup.removeView()。要更改UI，您应该/必须始终使用UI Thread。

编辑：在Handler上创建UIThread并使用mHandler.post(new Runnable());

Answer 3

在使用vGroup.removeView()旁边，您需要致电vGroup.refreshDrawableState()

在ViewGroup中删除View

3 个答案: