android联网代码

android APN的打开与关闭 
由于Android对于APN的网络API没有公开，不过我们可以阅读源代码，然后进行数 
据库操作，系统会自动监听数据库的变化，从而实现开启或者关闭APN。 
大家可以研究一下frameworks/base/core/java/android/provider 
/Telephony.java这个类， 
比较重要的就是 URI 和数据库字段： content://telephony/carriers 
字段可以在Telephony.java中找到。 
其实原理很简单 ： 
1 、 当开启APN的时候，设置一个正确的移动或者联通的APN 
2、 关闭的时候设置一个错误APN就会自动关闭网络 
看代码：Activity： 

Java代码 
package cc.mdev.apn; 
import java.util.ArrayList; 
import java.util.List; 
import android.app.Activity; 
import android.content.ContentValues; 
import android.database.Cursor; 
import android.net.Uri; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.View; 
import android.widget.Button; 

public class Main extends Activity { 

Uri uri = Uri.parse("content://telephony/carriers"); 
@Override 
public void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.main); 
Button open= (Button) findViewById(R.id.open); 
Button close= (Button) findViewById(R.id.close); 
open.setOnClickListener(new View.OnClickListener() { 
@Override 
public void onClick(View v) { 
openAPN(); 
} 
}); 
close.setOnClickListener(new View.OnClickListener() { 
@Override 
public void onClick(View v) { 
closeAPN(); 
} 
}); 
} 
public  void openAPN(){ 
List<APN> list = getAPNList(); 
for (APN apn : list) { 
ContentValues cv = new ContentValues(); 
cv.put("apn", APNMatchTools.matchAPN(apn.apn)); 
cv.put("type", APNMatchTools.matchAPN(apn.type)); 
getContentResolver().update(uri, cv, "_id=?", new String[]{apn.id}); 
} 
} 
public void closeAPN(){ 
List<APN> list = getAPNList(); 
for (APN apn : list) { 
ContentValues cv = new ContentValues(); 
cv.put("apn", APNMatchTools.matchAPN(apn.apn)+"mdev"); 
cv.put("type", APNMatchTools.matchAPN(apn.type)+"mdev"); 
getContentResolver().update(uri, cv, "_id=?", new String[]{apn.id}); 
} 
} 
private List<APN> getAPNList(){ 
String tag = "Main.getAPNList()"; 
//current不为空表示可以使用的APN 
String  projection[] = {"_id,apn,type,current"}; 
Cursor cr = this.getContentResolver().query(uri, projection, null, null, null); 
List<APN> list = new ArrayList<APN>(); 
while(cr!=null && cr.moveToNext()){ 
Log.d(tag, cr.getString(cr.getColumnIndex("_id")) + "  " + cr.getString(cr.getColumnIndex("apn")) + "  " + cr.getString(cr.getColumnIndex("type"))+ "  " + cr.getString(cr.getColumnIndex("current"))); 
APN a = new APN(); 
a.id = cr.getString(cr.getColumnIndex("_id")); 
a.apn = cr.getString(cr.getColumnIndex("apn")); 
a.type = cr.getString(cr.getColumnIndex("type")); 
list.add(a); 
} 
if(cr!=null) 
cr.close(); 
return list; 
} 
public static class APN{ 
String id; 
String apn; 
String type; 
} 
} 


APNMatchTools.java 
Java代码 
package cc.mdev.apn; 

public final class APNMatchTools { 
public static class APNNet{ 

public static String CMWAP = "cmwap"; 

public static String CMNET = "cmnet"; 
//中国联通3GWAP设置        中国联通3G因特网设置        中国联通WAP设置        中国联通因特网设置 
//3gwap                 3gnet                uniwap            uninet 

public static String GWAP_3 = "3gwap"; 

public static String GNET_3="3gnet"; 

public static String UNIWAP="uniwap"; 

public static String UNINET="uninet"; 
} 
public static String matchAPN(String currentName) { 
if("".equals(currentName) || null==currentName){ 
return ""; 
} 
currentName = currentName.toLowerCase(); 
if(currentName.startsWith(APNNet.CMNET)) 
return APNNet.CMNET; 
else if(currentName.startsWith(APNNet.CMWAP)) 
return APNNet.CMWAP; 
else if(currentName.startsWith(APNNet.GNET_3)) 
return APNNet.GNET_3; 
else if(currentName.startsWith(APNNet.GWAP_3)) 
return APNNet.GWAP_3; 
else if(currentName.startsWith(APNNet.UNINET)) 
return APNNet.UNINET; 
else if(currentName.startsWith(APNNet.UNIWAP)) 
return APNNet.UNIWAP; 
else if(currentName.startsWith("default")) 
return "default"; 
else return ""; 
// return currentName.substring(0, currentName.length() - SUFFIX.length()); 
} 
} 

最后不要忘记加上修改APN的权限： 
Xml代码 
   1. <uses-permission android:name="android.permission.WRITE_APN_SETTINGS"></uses-permission> 
<uses-permission android:name="android.permission.WRITE_APN_SETTINGS"></uses-permission> 
经过测试在G1 上联通和移动卡均是成功的。