AsyncTask 异步处理

package com.ch.day8_asynctaskdemo;

import java.util.ArrayList;

import com.ch.myutils.NetWorkUtil;

import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {
private EditText name;
private EditText pass;
private Button login;
Context mcontext;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mcontext = this;
init();
}

public void init(){
name = (EditText) findViewById(R.id.username);
pass = (EditText) findViewById(R.id.userpass);
login = (Button) findViewById(R.id.login);

login.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
String nameV = name.getText().toString();
String passV = pass.getText().toString();

//判断网路是否畅通加权限
if(NetWorkUtil.isNetAvailable(mcontext)){//网络畅通
//通过AsyncTask访问服务器

new MyAsyncTask().execute(nameV,passV,NetWorkUtil.LOGIN_URL);//调用MyAsyncTask执行请求
}
}
});
}
class MyAsyncTask extends AsyncTask<String, Integer, String>{
// 后台执行，比较耗时的操作都可以放在这里
@Override
protected String doInBackground(String... params) {//params的类型和AsyncTask类的第一个泛型对应
// TODO Auto-generated method stub
String uname = params[0];//得到用户名
String upass = params[1];//得到密码
String url = params[2];//得到url
String rs = NetWorkUtil.loginCheck_Get_HttpClient(uname, upass, url);//请求服务器。得到结果

return rs;//把请求的结果传递到onPostExecute方法中
}
//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
@Override
protected void onPostExecute(String result) {//result的类型和AsyncTask类的第三个泛型对应
// TODO Auto-generated method stub
login.setText(result);
//判断登陆的结果，决定是否跳转

// super.onPostExecute(result);
}

}

}

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;

}

}