Android下检测网络状态 3G WIFI

实现 代码如下

 

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。