Question

我有一个每10秒调用一次的webservice调用，应该使用webservice回复更新TextView（或者至少每10秒显示一次toast消息）

但是UI根本没有得到更新。

请找到以下代码。

public class MessagesRequestActivity extends Activity  {
    /** Called when the activity is first created. */
    String currentMsg="Default";
    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        //Calling the webservice
        getMessage();
    }
    public void getMessage(){

        try
        {
        SoapObject request = new SoapObject("http://tempuri.org/", "getMessage");

        SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
        envelope.dotNet = true;
        envelope.setOutputSoapObject(request);

        //Web method call
        HttpTransportSE androidHttpTransport = new HttpTransportSE("http://192.168.4.50/WebService.asmx");
        androidHttpTransport.call("http://tempuri.org/"+ "getMessage", envelope);
        //get the response
        SoapPrimitive response = (SoapPrimitive)envelope.getResponse();

        //the response object can be retrieved by its name: result.getProperty("objectName");
        String message = (String)response.toString();
        Toast.makeText(this, message, Toast.LENGTH_LONG).show();

        }
        catch (Exception e)
        {
        e.printStackTrace();
        }
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        }
}

Answer 1

正如大家所提到的，你在UI线程中进行网络调用并执行Thread.Sleep（），冻结你的UI。

我尝试使用类似AsyncHttpClient的类，它具有您需要的所有功能，您必须在回调中执行UI更新。

http://loopj.com/android-async-http/

Answer 2

以下是AsyncTask

的示例

public class TalkToServer extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
    super.onPreExecute();
}

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

}

@Override
protected String doInBackground(String... params) {
//do your work here
    return something;
}

@Override
protected void onPostExecute(String result) {
    super.onPostExecute(result);
       // do something with data here-display it or send to mainactivity
}

然后您可以通过致电

进行访问

TalksToServer varName = new TalkToServer(); //pass parameters if you need to the constructor
varName.execute();

Async Docs Progress Dialog Example

您不想在sleep主题上执行网络内容或致电UI。如果它是内部类，那么您将可以访问外部类的成员变量。否则，如果要从AsyncTask或其他方法besids context进行更新，请在onPostExecute类中创建一个传递doInBackground()的构造函数。

在Android中异步更新UI

2 个答案: