AsyncTask 异步处理

 1 package com.ch.day8_asynctaskdemo;
 2 
 3 import java.util.ArrayList;
 4 
 5 import com.ch.myutils.NetWorkUtil;
 6 
 7 import android.os.AsyncTask;
 8 import android.os.Bundle;
 9 import android.app.Activity;
10 import android.content.Context;
11 import android.util.Log;
12 import android.view.Menu;
13 import android.view.View;
14 import android.view.View.OnClickListener;
15 import android.widget.Button;
16 import android.widget.EditText;
17 
18 public class MainActivity extends Activity {
19     private EditText name;
20     private EditText pass;
21     private Button login;
22     Context mcontext;
23     
24     @Override
25     protected void onCreate(Bundle savedInstanceState) {
26         super.onCreate(savedInstanceState);
27         setContentView(R.layout.activity_main);
28         mcontext = this;
29         init();
30     }
31     
32     public void init(){
33         name = (EditText) findViewById(R.id.username);
34         pass = (EditText) findViewById(R.id.userpass);
35         login = (Button) findViewById(R.id.login);
36         
37         login.setOnClickListener(new OnClickListener() {
38             @Override
39             public void onClick(View v) {
40                 String nameV = name.getText().toString();
41                 String passV = pass.getText().toString();
42                 
43                 //判断网路是否畅通加权限
44                 if(NetWorkUtil.isNetAvailable(mcontext)){//网络畅通
45                     //通过AsyncTask访问服务器
46                     
47                     new MyAsyncTask().execute(nameV,passV,NetWorkUtil.LOGIN_URL);//调用MyAsyncTask执行请求
48                 }
49             }
50         });
51     }
52     class MyAsyncTask extends AsyncTask<String, Integer, String>{
53         // 后台执行，比较耗时的操作都可以放在这里
54         @Override
55         protected String doInBackground(String... params) {//params的类型和AsyncTask类的第一个泛型对应
56             // TODO Auto-generated method stub
57             String uname = params[0];//得到用户名
58             String upass = params[1];//得到密码
59             String url = params[2];//得到url
60             String rs = NetWorkUtil.loginCheck_Get_HttpClient(uname, upass, url);//请求服务器。得到结果
61             
62             return rs;//把请求的结果传递到onPostExecute方法中
63         }
64         //相当于Handler 处理UI的方式，在这里面可以使用在doInBackground 得到的结果处理操作UI
65         @Override
66         protected void onPostExecute(String result) {//result的类型和AsyncTask类的第三个泛型对应
67             // TODO Auto-generated method stub
68             login.setText(result);
69             //判断登陆的结果，决定是否跳转
70             
71 //            super.onPostExecute(result);
72         }
73         
74     }
75 
76 
77 }

package com.ch.myutils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.util.EntityUtils;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

public class NetWorkUtil {
    public static final String LOGIN_URL = "http://169.254.109.73:8080/serverof1407a/loginServlet";
    public static boolean isNetAvailable(Context context){
        //获得网络管理器
        ConnectivityManager connM = 
                (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo netInfo = connM.getActiveNetworkInfo();//得到网络详情
        
        if(netInfo == null || !netInfo.isAvailable())
            return false;
        
        return true;
    }
    
    public static String loginCheck_Get_HttpClient(String name,String pass,String url){
        //通过StringBuffer来加工url
        StringBuffer sb = new StringBuffer(url);
        sb.append("?username=");
        sb.append(name);
        sb.append("&userpass=");
        sb.append(pass);
        
        String result = "";
        
        HttpGet get = new HttpGet(sb.toString());//创建httpClient的get请求对象
        //设置请求参数
        HttpParams params = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(params, 5*1000);
        HttpConnectionParams.setSoTimeout(params, 5*1000);
        
        HttpClient client = new DefaultHttpClient(params);//创建HttpClient对象
        
        try {
            HttpResponse res = client.execute(get);//执行请求，获得结果
            if(res.getStatusLine().getStatusCode() == 200){
                HttpEntity entity = res.getEntity();//获得相应结果，是一个HttpEntity对象
                result = EntityUtils.toString(entity, "utf-8");//转换为字符串
            }
        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return result;
        
    }

    
}