Android判断设备网络连接状态及判断连接方式的方法

/** 
* 检测网络是否连接 
* @return 
*/ 
private boolean checkNetworkState() {
   boolean flag = false;
   //得到网络连接信息
   manager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); 
   //去进行判断网络是否连接
   if (manager.getActiveNetworkInfo() != null) {
     flag = manager.getActiveNetworkInfo().isAvailable();
   }
   if (!flag) {
     setNetwork();
   } else {
     isNetworkAvailable();
   }
   return flag;
}
/**
* 网络未连接时，调用设置方法
*/
private void setNetwork(){
   Toast.makeText(this, "wifi is closed!", Toast.LENGTH_SHORT).show();
   AlertDialog.Builder builder = new AlertDialog.Builder(this);
   builder.setIcon(R.drawable.ic_launcher);
   builder.setTitle("网络提示信息");
   builder.setMessage("网络不可用，如果继续，请先设置网络！");
   builder.setPositiveButton("设置", new OnClickListener() {
     @Override
     public void onClick(DialogInterface dialog, int which) {
       Intent intent = null;
       /**
       * 判断手机系统的版本！如果API大于10 就是3.0+
       * 因为3.0以上的版本的设置和3.0以下的设置不一样，调用的方法不同
       */
       if (android.os.Build.VERSION.SDK_INT > 10) {
         intent = new Intent(android.provider.Settings.ACTION_WIFI_SETTINGS);
       } else {
         intent = new Intent();
         ComponentName component = new ComponentName(
             "com.android.settings",
             "com.android.settings.WirelessSettings");
         intent.setComponent(component);
         intent.setAction("android.intent.action.VIEW");
       }
       startActivity(intent);
     }
   });
   builder.setNegativeButton("取消", new OnClickListener() {
     @Override
     public void onClick(DialogInterface dialog, int which) {
     }
   });
   builder.create();
   builder.show();
}
/**
* 网络已经连接，然后去判断是wifi连接还是GPRS连接
* 设置一些自己的逻辑调用
*/
private void isNetworkAvailable(){
   State gprs = manager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState();
  State wifi = manager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState();
  if(gprs == State.CONNECTED || gprs == State.CONNECTING){
    Toast.makeText(this, "wifi is open! gprs", Toast.LENGTH_SHORT).show();
  }
  //判断为wifi状态下才加载广告，如果是GPRS手机网络则不加载！
  if(wifi == State.CONNECTED || wifi == State.CONNECTING){
    Toast.makeText(this, "wifi is open! wifi", Toast.LENGTH_SHORT).show();
    loadAdmob();
  }
}