Android网络编程之使用HttpClient进行Get方式通信

标签：android   网络编程   httpclient   httpget   

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <LinearLayout 
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:orientation="horizontal" >

		<TextView
		    android:layout_width="wrap_content"
		    android:layout_height="wrap_content"
		    android:layout_weight="1"
		    android:gravity="center"
		    android:text="城市："
		    android:textSize="23sp" />

		<EditText 
            android:id="@+id/city"
            android:layout_width="wrap_content"
			android:layout_height="wrap_content"
			android:layout_weight="3"
            android:inputType="text" />"
    </LinearLayout>

    <Button
        android:id="@+id/query"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:text="查询" 
        android:textSize="23sp" />
    
    <TextView
		android:id="@+id/result"
		android:layout_width="match_parent"
		android:layout_height="match_parent" />
</LinearLayout>

Java源代码文件：MainActivity.java

package com.rainsong.httpclientgetdemo;

import java.io.IOException;
import java.net.URLEncoder;
import java.util.ArrayList;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import android.os.Bundle;
import android.os.StrictMode;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
    private static final String JUHE_URL_ENVIRONMENT_AIR_PM = 
                                    "http://web.juhe.cn:8080/environment/air/pm";
    private static final String JUHE_APPKEY = "你申请的APPKEY值";
    EditText et_city;
    Button btn_query;
    TextView tv_result;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // 强制直接在UI线程中进行网络操作
        StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
            .detectDiskReads().detectDiskWrites().detectNetwork()
            .penaltyLog().build());
        StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
            .detectLeakedSqlLiteObjects().detectLeakedClosableObjects()
            .penaltyLog().penaltyDeath().build());

        setContentView(R.layout.activity_main);
        et_city = (EditText)findViewById(R.id.city);
        tv_result = (TextView)findViewById(R.id.result);
        btn_query = (Button)findViewById(R.id.query);
        btn_query.setOnClickListener(new OnClickListener() {
            public void onClick(View view) {
                tv_result.setText("");
                String city;
                city = et_city.getText().toString();
                if (city.length() < 1) {
                    Toast.makeText(MainActivity.this, "请输入城市名",
                            Toast.LENGTH_LONG).show();
                    return;
                }
                ArrayList<NameValuePair> headerList = new ArrayList<NameValuePair>();
                headerList.add(new BasicNameValuePair("Content-Type",
                        "text/html; charset=utf-8"));
                String targetUrl = JUHE_URL_ENVIRONMENT_AIR_PM;
                ArrayList<NameValuePair> paramList = new ArrayList<NameValuePair>();
                paramList.add(new BasicNameValuePair("key", JUHE_APPKEY));
                paramList.add(new BasicNameValuePair("dtype", "json"));
                paramList.add(new BasicNameValuePair("city", city));
                
                for (int i = 0; i < paramList.size(); i++) {
                    NameValuePair nowPair = paramList.get(i);
                    String value = nowPair.getValue();
                    try {
                        value = URLEncoder.encode(value, "UTF-8");
                    } catch (Exception e) {
                        
                    }
                    if (i == 0) {
                        targetUrl += ("?" + nowPair.getName() + "=" + value);
                    } else {
                        targetUrl += ("&" + nowPair.getName() + "=" + value);
                    }
                }

                HttpGet httpRequest = new HttpGet(targetUrl);
                try {
                    for (int i = 0; i < headerList.size(); i++) {
                        httpRequest.addHeader(headerList.get(i).getName(),
                                                headerList.get(i).getValue());
                    }

                    HttpClient httpClient = new DefaultHttpClient();

                    HttpResponse httpResponse = httpClient.execute(httpRequest);
                    if (httpResponse.getStatusLine().getStatusCode() == 200) {
                        String strResult = EntityUtils.toString(httpResponse.getEntity());
                        tv_result.setText(strResult);
                    } else {
                        Toast.makeText(MainActivity.this, "查询失败",
                                Toast.LENGTH_LONG).show();
                        tv_result.setText("");
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

注：本来不应该直接在UI线程进行网络操作，会阻塞UI，影响用户体验。但为了不引入其他知识点，把焦点聚集在HttpClient网络通信上，在本例中强制直接在UI线程中进行网络操作。在下篇文章中会介绍如何避免直接在UI线程中进行网络操作。

Android网络编程之使用HttpClient进行Get方式通信

标签：android   网络编程   httpclient   httpget   

原文地址：http://blog.csdn.net/hantangsongming/article/details/42121091