android 网络连接操作

1. Manifest配置

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

2.检查网络连接状态 未连接显示提示信息，连接执行网络连接操作

示例代码：

public void myClickHandler(View view) {
...
ConnectivityManager connMgr = (ConnectivityManager)
getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected()) {
// fetch data
} else {
// display error
}
...
}

3.改造官方文档写的一个tool类

HttpUtils.java

 

package com.example.yueyundong1.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class HttpUtils {
public static String getJsonContent(String path) {
try {
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setConnectTimeout(15000);
conn.setReadTimeout(10000);
conn.setRequestMethod("GET");
conn.setDoInput(true);
conn.connect();
int responseCode = conn.getResponseCode();

if (responseCode == 200)
return changeInputStream(conn.getInputStream());
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
public static String changeInputStream(InputStream inputStream) {
Reader reader;
String contentAsString=null;
try {
reader = new InputStreamReader(inputStream, "UTF-8");
char[] buffer = new char[1024];
reader.read(buffer);
contentAsString = new String(buffer);

} catch (UnsupportedEncodingException e) {
e.printStackTrace();
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return contentAsString;
}
}

4.由第3步得到的jsonString构造JSONObject 然后解析相要的数据