Android network status 3G/WIFI

package Android.HelloAndroid; 

import android.app.Activity; 

import android.app.AlertDialog; 

import android.content.Context; 

import android.os.Bundle; 

import android.widget.TextView; 

import android.net.ConnectivityManager; 

import android.net.NetworkInfo; 

import android.net.NetworkInfo.State; 

public class Hello extends Activity { 

/** Called when the activity is first created. */ 

@Override 

public void onCreate(Bundle savedInstanceState) { 

super.onCreate(savedInstanceState); 

TextView tv = new TextView(this); 

tv.setText("检测网络状态"); 

setContentView(tv); 

checkNetworkInfo(); 

goodNet(); 

} 

public boolean goodNet() 

{ 

ConnectivityManager manager = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE); 

NetworkInfo networkinfo = manager.getActiveNetworkInfo(); 

if (networkinfo == null || !networkinfo.isAvailable()) { 

new AlertDialog.Builder(this).setMessage("没有可以使用的网络").setPositiveButton("Ok", null).show(); 

return false; 

} 

new AlertDialog.Builder(this).setMessage("网络正常可以使用").setPositiveButton("Ok", null).show(); 

return true; 

} 

private void checkNetworkInfo() 

{ 

ConnectivityManager conMan = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); //mobile 3G Data Network 

State mobile = conMan.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState(); 

new AlertDialog.Builder(this).setMessage(mobile.toString()).setPositiveButton("3G", null).show();//显示3G网络连接状态 

State wifi = conMan.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState(); 

new AlertDialog.Builder(this).setMessage(wifi.toString()).setPositiveButton("WIFI", null).show();//显示wifi网络连接状态 

} 

} 

需要注意:

根据Android的安全机制，在使用ConnectivityManager时，必须在AndroidManifest.xml中添加<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> 否则无法获得系统的许可。