Question

In my app when I click on a menu button it will go to an activity where I will load data and images from a remote server to a custom list view. The problem is if the WiFi is switched off, I’m getting a crash in the second activity. I have put the code in the try catch block and set the adapter to null in the catch section.So when i click the button it will go the activity and if the WiFi is off, since i set adapter = null in the catch activity will be shown with out a list view. How can i stay in the menu screen with out getting a crash. Any idea?

        Intent mainIntent = new Intent( SplashScreenActivity.this, GiftListActivity.class );
        SplashScreenActivity.this.startActivity( mainIntent );

This is my call to the second activity.

try{
    adapter = new GiftJewelryListAdapter(GiftListActivity.this, giftlist);
    itemsListView.setAdapter(adapter);
}
catch(Exception e){
    adapter=null;
    MyAlertDialog.ShowAlertDialog(GiftJewelryListActivity.this, "", "Check Network Connection", "OK");
}

I want to stay in the activity from which i called, after showing the message “check network connection”.What change should i do here?

Answer 1

You can check network availability in the activity from which you called the new activity. If a network is available, you can start the new activity.

The below function is used to detect whether device is connected to a network or not.

 public static boolean isNetworkAvailable(Context context) {
     ConnectivityManager connectivity = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
     if (connectivity != null) {
        NetworkInfo[] info = connectivity.getAllNetworkInfo();
        if (info != null) {
           for (int i = 0; i < info.length; i++) {
              if (info[i].getState() == NetworkInfo.State.CONNECTED) {
                 return true;
              }
           }
        }
     }
     return false;
  }

You can invoke the function as shown below…

if(!isNetworkAvailable(context))
     MyAlertDialog.ShowAlertDialog(GiftJewelryListActivity.this, "", "Check Network Connection", "OK")
else{
     Intent mainIntent = new Intent( SplashScreenActivity.this, GiftListActivity.class );
     SplashScreenActivity.this.startActivity( mainIntent );
}

Dont forget to add permission in Manifest.XMl .

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> 

Hope it helps..