使用 AsyncTask 在 ListView 中显示 Web 服务数据

Question

喂，

当我单击按钮时，我从 Web 服务获取数据并将其发布到列表视图中，但我不想单击按钮。当我打开程序时，首先加载列表视图，然后它向我显示数据.

这是我的代码（此代码有效）

package com.example.karayel.wcf;


import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;


import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;


public class MainActivity extends ActionBarActivity {

    private static final String SOAP_ACTION = "http://tempuri.org/IService/AllUserName";
    private static final String METHOD_NAME = "AllUserName";
    private static final String NAMESPACE = "http://tempuri.org/";
    private static final String URL = "http://10.0.2.2:50006/WCFService2/Service.svc?wsdl";
    String[] userNames = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button =(Button)findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Thread networkThread = new Thread() {
                    @Override
                    public void run() {
                        try {
                            SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
                            SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
                            envelope.bodyOut = request;
                            envelope.dotNet = true;
                            envelope.setOutputSoapObject(request);
                            HttpTransportSE ht = new HttpTransportSE(URL);
                            ht.call(SOAP_ACTION, envelope);
                            SoapObject result = (SoapObject)envelope.getResponse();
                            userNames = new String[result.getPropertyCount()];
                            for(int i=0;i<result.getPropertyCount();i++){
                                userNames[i]=result.getPropertyAsString(i);
                            }
                            runOnUiThread(new Runnable() {
                                public void run() {

                                    //(A) adım
                                    ListView listemiz=(ListView) findViewById(R.id.listView);

                                    //(B) adım
                                    ArrayAdapter<String> veriAdaptoru=new ArrayAdapter<String>
                                            (MainActivity.this, android.R.layout.simple_list_item_1, android.R.id.text1, userNames);

                                    //(C) adım
                                    listemiz.setAdapter(veriAdaptoru);
                                }
                            });
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                };
                networkThread.start();
            }
        });
}

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

我想用 AsyncTask 重写代码。我该怎么做？

谢谢...

Answer 1

public class MainActivity extends AppCompatActivity {

    private static final String SOAP_ACTION = "http://tempuri.org/IService/AllUserName";
    private static final String METHOD_NAME = "AllUserName";
    private static final String NAMESPACE = "http://tempuri.org/";
    private static final String URL = "http://10.0.2.2:50006/WCFService2/Service.svc?wsdl";
    String[] userNames = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new AsyncTask<Void , Void, String[]>(){

            @Override
            protected String[] doInBackground(Void... params) {
                // TODO Auto-generated method stub
                SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
                SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
                envelope.bodyOut = request;
                envelope.dotNet = true;
                envelope.setOutputSoapObject(request);
                HttpTransportSE ht = new HttpTransportSE(URL);
                ht.call(SOAP_ACTION, envelope);
                SoapObject result = (SoapObject)envelope.getResponse();
                userNames = new String[result.getPropertyCount()];
                for(int i=0;i<result.getPropertyCount();i++){
                    userNames[i]=result.getPropertyAsString(i);
                }
                return userNames;
            }
            @Override
            protected void onPostExecute(String[] result){
                 //(A) adım
                ListView listemiz=(ListView) findViewById(R.id.listView);

                //(B) adım
                ArrayAdapter<String> veriAdaptoru=new ArrayAdapter<String>
                        (MainActivity.this, android.R.layout.simple_list_item_1, android.R.id.text1, result);

                //(C) adım
                listemiz.setAdapter(veriAdaptoru);
            }
        }.execute();
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Answer 2

您有很多选择，其中一些如下所示：

• 为此，您应该从onClick() 中删除所有代码，并将所有内容写入您活动的onCreate() 方法中。

• 试试这个：findViewById(R.id.button).performClick();