判断网络状态进行网络加载等操作

@Override
protected void onResume() {
   Log.i("lzan13", "onResume");
   checkNetworkState();
   super.onResume();
}

/**
 * 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();
    }
   
}

/**
 * 在wifi状态下 加载admob广告
 */
private void loadAdmob(){
   ll = (LinearLayout) findViewById(R.id.load_ads);
   ll.removeAllViews();
   adsView = new AdView(this, AdSize.BANNER, "a15194a1ac9505d");
   ll.addView(adsView);

   adsView.loadAd(new AdRequest());
}