Android采用Volley具体的例子展示完整的异步加载数据(一)

MainActivity例如下列:

package cc.cn;

import java.util.HashMap;
import org.json.JSONObject;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import com.android.volley.AuthFailureError;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.Request.Method;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
/**
 * Demo描写叙述:
 * 去年一个项目中简单的使用了Volley,參见:
 * lfdfhl/article/details/12223345
 * 近期guolin写了几篇文章具体介绍Volley,所以在此比較系统地学习一下.
 * 在本演示样例中,主要包含:
 * 1 利用Volley实现Get请求
 * 2 利用Volley实现Post请求
 * 3 利用Volley实现Json数据请求
 * 
 * 注意事项:
 * 1 引入jar包volley.jar
 * 2 网络权限<uses-permission android:name="android.permission.INTERNET"/>
 * 
 * 学习资料:
 * guolin_blog/article/details/17482095
 * Thank you very much
 *
 */
public class MainActivity extends Activity {
    private RequestQueue mRequestQueue;
    private StringRequest mStringRequest;
    private Context mContext;
    private JsonObjectRequest mJsonObjectRequest;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        volley_get();
        //volley_post();
        //volley_json();
    }



    //利用Volley实现Get请求
    private void volley_get(){
        mContext=this;
        String url="http://www.baidu.com/";
        //1 创建RequestQueue对象
        mRequestQueue=Volley.newRequestQueue(mContext);
        //2 创建StringRequest对象
        mStringRequest = new StringRequest(
                url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        System.out.println("请求结果:"+response);
                    }
                }, 
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        System.out.println("请求错误:"+error.toString());
                    }
                });
        //3 将StringRequest加入到RequestQueue
        mRequestQueue.add(mStringRequest);
    }

    //利用Volley实现Post请求
    private void volley_post() {
        String url = "http://hxyj.cwwic.cn/wap/api_cs/user.php?action=login";
        mContext = this;
        mRequestQueue = Volley.newRequestQueue(mContext);
        mStringRequest = new StringRequest(
                Method.POST, 
                url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        System.out.println("请求结果:" + response);
                    }
                }, 
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        System.out.println("请求错误:" + error.toString());
                    }
                }) {
            //携带參数
            @Override
            protected HashMap<String, String> getParams()throws AuthFailureError {
                HashMap<String, String> hashMap = new HashMap<String, String>();
                hashMap.put("un", "411111222");
                hashMap.put("pw", "180034111");
                return hashMap;
            }

        };
        mRequestQueue.add(mStringRequest);

    }

     //利用Volley实现Json数据请求
    private void volley_json() {
        mContext = this;
        String url = "http://m.weather.com.cn/data/101010100.html";
        // 1 创建RequestQueue对象
        mRequestQueue = Volley.newRequestQueue(mContext);
        // 2 创建JsonObjectRequest对象
        mJsonObjectRequest = new JsonObjectRequest(
                url, 
                null,
                new Response.Listener<JSONObject>() {
                    @Override
                    public void onResponse(JSONObject response) {
                        System.out.println("请求结果:" + response.toString());
                    }
                }, 
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        System.out.println("请求错误:" + error.toString());
                    }
                });

        // 3 将JsonObjectRequest加入到RequestQueue
        mRequestQueue.add(mJsonObjectRequest);

    }



}

main.xml例如以下:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="学习Volley(一)" 
        android:layout_centerInParent="true"
     />

</RelativeLayout>

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