android 登录前检查网络状态
package com.dx;import android.app.Activity;import android.app.AlertDialog;import android.content.Context;import android.net.ConnectivityManager;import android.net.NetworkInfo;import android.net.NetworkInfo.State;import android.os.Bundle;import android.widget.TextView;public class Main extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);// setContentView(R.layout.main); TextView textView = new TextView(this); textView.setText("网络检测"); setContentView(textView); if(checkNetWorkInfo()){ goToNetWork(); }; }private boolean goToNetWork() {// TODO Auto-generated method stubConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo info = connectivityManager.getActiveNetworkInfo();if(info == null || !info.isAvailable()){new AlertDialog.Builder(this).setMessage("没有可以使用的网络").setPositiveButton("Ok", null).show(); return false;}else{new AlertDialog.Builder(this).setMessage("网络正常可以使用").setPositiveButton("Ok", null).show(); return true;}}private boolean checkNetWorkInfo() {// TODO Auto-generated method stubConnectivityManager manager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);State wifi = manager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState();if(wifi != null){new AlertDialog.Builder(this).setMessage(wifi.toString()).setPositiveButton("wifi", null).show();//显示wifi网络连接状态 return true;}else{State mobile = manager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState();if(mobile != null){new AlertDialog.Builder(this).setMessage(mobile.toString()).setPositiveButton("3G", null).show();//显示3G网络连接状态 return true;}}return false;}}??