AsyncTask 异步处理

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 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     @Override25     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             @Override39             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         @Override55         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 stub57             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url60             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UI65         @Override66         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 stub68             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;            }    }

 

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