在OnclickListener AsyncTask的崩溃 [英] Asynctask crashes in OnclickListener

问题描述

我很新到Android希望你有人可以帮助我。
每当我使用OnclickListener来执行的AsyncTask，程序会崩溃。如果我不使用onclicklistener执行的AsyncTask，测试程序工作正常。

I am very new to Android hope you anyone could help me. Whenever I use an OnclickListener to execute an Asynctask, the program will crash. If I execute the Asynctask without using onclicklistener, the testing program works fine.

public class MainActivity extends Activity {

TextView label;
Button start;
MyAsyncTask test;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    label = (TextView)findViewById(R.id.tvIndicator);
    start = (Button)findViewById(R.id.btSend);

    test = new MyAsyncTask();

    start.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            test.execute();
        }
    });     
}

public class MyAsyncTask extends AsyncTask{
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("htt://****.php");//left out the address

    @Override
    protected Object doInBackground(Object... params) {
        // TODO Auto-generated method stub

            label.setText("Please Work");

            String MyName = "testing"; 
            String response = null;
            try {

            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
            nameValuePairs.add(new BasicNameValuePair("emailAdd", MyName));
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

            ResponseHandler<String> responseHandler = new BasicResponseHandler();
            response = httpclient.execute(httppost, responseHandler);

            label.setText(response.length());
            return response;

            } catch (Exception e) {
                e.printStackTrace();
            }   

        return null;
    }
}

}

推荐答案

您不能更新在主题从 UI线程不同的UI元素 iteself。你必须使用处理程序或使用 runOnUiThread

you can not update UI element in a Thread different from the UI Thread iteself. You have to use an Handler or use runOnUiThread

例如

runOnUiThread(new Runnable() {
      public void run() {
         label.setText("Please Work");
       }
 });

这篇关于在OnclickListener AsyncTask的崩溃的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！