需要从AsyncTask返回值

Question

我正在调用soap webservice并需要显示返回的内容.但我不能这样做,因为AsyncTask很复杂,我不知道如何正确使用它.你能告诉我如何通过asynctask从被调用函数返回数据吗？

这是我的代码

public class WebserviceTool {

private final String NAMESPACE = "http://tempuri.org/";
private final String URL = "http://192.168.0.11:9289/Service1.asmx";
private final String SOAP_ACTION = "http://tempuri.org/get_currency";
private final String METHOD_NAME = "get_currency";

public static void main(String[] args) {
    // TODO Auto-generated method stub
}

public String execute_barcode_webservice(String s1, String s2) {
    //Create request
    SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
    request.addProperty("date",s1);
    request.addProperty("cur_code",s2);
    //Create envelope
    SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
    envelope.dotNet = true;
    envelope.encodingStyle = SoapEnvelope.ENC;
    envelope.setOutputSoapObject(request);
    HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);

            Object response;
    try {
        androidHttpTransport.call(SOAP_ACTION, envelope);
        response = (Object) envelope.getResponse();
        Log.i("my_error", response.toString());
    } catch (Exception e) {
        Log.i("my_error", e.getMessage().toString());
    }
    return "testarif";
}

public class AsyncCallWS extends AsyncTask<String, Void, Void> {
    @Override
    protected Void doInBackground(String... params) {
        try {
            execute_barcode_webservice(params[0], params[1]);
        } catch (Exception e) {
            // TODO: handle exception
        }   
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {

    }

    @Override
    protected void onPreExecute() {

    }

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

    }
}
}

这是执行所有作业并返回数据的函数execute_barcode_webservice().但是因为我调用execute_barcode_webservice()查看AsyncTask,我不知道如何返回它.我该怎么做？

Answer 1

异步任务执行的结果是由response生成的对象execute_barcode_webservice().但是,不要将异步任务视为将执行并向您返回值的事物.相反,在方法内部,onPostExecute()您必须获取response对象并对其进行处理(提取其值并将其显示在列表中,或者您要对其执行的任何操作).异步任务只是一种在单独的线程中执行某些代码然后返回主线程(UI线程)并处理结果的方法,这是完成的onPostExecute().

我的建议:重写exe​​cute_barcode_webservice()以返回一个response对象而不是一个String(null如果操作失败可以是一个对象)并将该对象传递给该onPostExecute()方法.您必须将异步任务更改为:

public class AsyncCallWS extends AsyncTask<String, Void, Object> {
    @Override
    protected Object doInBackground(String... params) {
        Object response = null;
        try {
            response = execute_barcode_webservice(params[0], params[1]);
        } catch (Exception e) {
            // TODO: handle exception
        }   
        return response;
    }

    @Override
    protected void onPostExecute(Object response) {
        if (response != null) {
            // display results in a list or something else
        }
    }