Question

我想将文字附加到从doInBackground返回的Edittext。

我的代码如下所示：

  public  void  openFile() {
             progressDialog.show();


      new AsyncTask<Void,String,Void>(){

          @Override
          protected Void doInBackground(Void... voids) {
                    File file = new File("/some file");
                    BufferedReader br = new
                            BufferedReader(new FileReader(file));
                    String line;

                    while ((line = br.readLine()) !=  null) {
                        onProgressUpdate(line);
                    }
                    br.close();
                } catch (IOException e) {
                }

          }
            return null;
        }

        @Override
        protected void onProgressUpdate(String... values) {

            final String line = values[0].toString();

                for (char c : line.toCharArray()) {
                       inputEditText.append(Character.toString(c));
                 }    

       }

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


    }.execute();

}

如果我删除onProgressUpdate中的代码，则应用程序正在运行且没有错误。

如何解决这个问题??

错误：

java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:200)
        at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
        at java.lang.Thread.run(Thread.java:1019)
 Caused by: android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
        at android.view.ViewRoot.checkThread(ViewRoot.java:3041)
        at android.view.ViewRoot.invalidateChild(ViewRoot.java:647)
        at android.view.ViewRoot.invalidateChildInParent(ViewRoot.java:673)
        at android.view.ViewGroup.invalidateChild(ViewGroup.java:2511)
        at android.view.View.invalidate(View.java:5279)
        at android.widget.TextView.updateAfterEdit(TextView.java:5104)
        at android.widget.TextView.handleTextChanged(TextView.java:6617)
        at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:6775)
        at android.text.SpannableStringBuilder.sendTextChange(SpannableStringBuilder.java:889)
        at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:352)
        at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:269)
        at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:432)
        at android.text.SpannableStringBuilder.append(SpannableStringBuilder.java:259)
        at android.text.SpannableStringBuilder.append(SpannableStringBuilder.java:28)
        at android.widget.TextView.append(TextView.java:2334)
        at android.widget.TextView.append(TextView.java:2321)
        at com.example.sa.myapplication.MainActivity$7.onProgressUpdate(MainActivity.java:358)

Answer 1

您直接从onProgressUpdate(line);致电doInBackground，您需要使用publishProgress。

更改onProgressUpdate(line);

的publishProgress(line);

http://developer.android.com/reference/android/os/AsyncTask.html#publishProgress%28Progress...%29

http://developer.android.com/intl/es/guide/components/processes-and-threads.html

在向EditText附加文本时在AsyncTask中获取错误

1 个答案: