1起来开发Android的天气软件（三）——使用Volley实现网络通信

package com.melhc.util;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class HttpUtil {
	/*
	 * 从服务器端获取省县市的数据
	 */
	public static void sendHttpRequest(final String address,
			final HttpCallbackListener listener) {
		new Thread(new Runnable() {
			@Override
			public void run() {
				// TODO Auto-generated method stub
				HttpURLConnection connection = null;
				try {
					//创建一个url对象
					URL url = new URL(address);
					//通过url对象获取HTTPURLCONNCETION实例
					connection = (HttpURLConnection) url.openConnection();
					//设置http的请求所使用的方法为get方法
					connection.setRequestMethod("GET");
					//自由定制一些属性，比如设置连接超时，读取超时的毫秒数
					connection.setConnectTimeout(8000);
					connection.setReadTimeout(8000);
					//获得服务器返回的输入流
					InputStream in = connection.getInputStream();
					//将得到的输入流装换成String字符串
					BufferedReader reader = new BufferedReader(
							new InputStreamReader(in, "utf-8"));
					StringBuffer response = new StringBuffer();
					String line;
					while ((line = reader.readLine()) != null) {
						response.append(line);
					}
					LogUtil.i("HTTPUtil",
							"------------------>" + response.toString());
					if (listener != null) {
						listener.onFinish(response.toString());
					}
				} catch (Exception e) {
					// TODO: handle exception
					if (listener != null) {
						listener.onError(e);
					}
				} finally {
					if (connection != null) {
						connection.disconnect();
					}
				}
			}
		}).start();
	}
}

package com.melhc.util;

/*
 *  网路连接的回掉接口
 */
public interface HttpCallbackListener {
	void onFinish(String response);

	void onError(Exception e);
}

HttpUtil.sendHttpRequest(address, new HttpCallbackListener() {

			@Override
			public void onFinish(String response) {
				// TODO Auto-generated method stub
				boolean result = false;
				if ("province".equals(type)) {
					result = Utility
							.handleProvicesResponse(weatherDB, response);
				} else if ("city".equals(type)) {
					result = Utility.handleCitiesResponse(weatherDB, response,
							selectedProvince);
				} else if ("county".equals(type)) {
					result = Utility.handleCountiesResponse(weatherDB,
							response, selectedCity);
				}

三、Volley实现网络通信

          1. 创建一个RequestQueue对象。

          2. 创建一个StringRequest对象。

          3. 将StringRequest对象添加到RequestQueue里面。

          具体的代码实现如下所示

RequestQueue mQueue = Volley.newRequestQueue(getApplicationContext());
		StringRequest stringRequest = new StringRequest(address,
				new Response.Listener<String>() {
					@Override
					public void onResponse(String response) {
						LogUtil.i("TAG", "---------------->"+response);
						boolean result = false;
						if ("province".equals(type)) {
							result = Utility.handleProvicesResponse(weatherDB,
									response);
						} else if ("city".equals(type)) {
							result = Utility.handleCitiesResponse(weatherDB,
									response, selectedProvince);
						} else if ("county".equals(type)) {
							result = Utility.handleCountiesResponse(weatherDB,
									response, selectedCity);
						}
						if (result) {
							// 通过runonUiMainThread方法返回主线程处理逻辑
							runOnUiThread(new Runnable() {
								@Override
								public void run() {
									// TODO Auto-generated method stub
									closeProgressDialog();
									if ("province".equals(type)) {
										queryProvinces();
									} else if ("city".equals(type)) {
										queryCities();
									} else if ("county".equals(type)) {
										queryCounties();
									}
								}
							});
						}
					}
				}, new Response.ErrorListener() {
					@Override
					public void onErrorResponse(VolleyError error) {
						LogUtil.i("TAG", "-------------------->" + error);
						runOnUiThread(new Runnable() {
							@Override
							public void run() { // TODO Auto-generated method
												// stub //
								closeProgressDialog();
								Toast.makeText(getApplicationContext(),
										"加载数据失败！", Toast.LENGTH_SHORT).show();
							}
						});
					}
				});
		mQueue.add(stringRequest);

 RequestQueue mQueue = Volley.newRequestQueue(context); 

 StringRequest stringRequest = new StringRequest(address,  
                        new Response.Listener<String>() {  
                            @Override  
                            public void onResponse(String response) {  
                                Log.d("TAG", response);  
                            }  
                        }, new Response.ErrorListener() {  
                            @Override  
                            public void onErrorResponse(VolleyError error) {  
                                Log.e("TAG", error.getMessage(), error);  
                            }  
                        });  

    mQueue.add(stringRequest);