Passing reference to activity to utility class android

Question

I realise this question has been asked many times, but I am still unable to completely understand this concept. In my application, I am using a static utility class to keep common methods (like showing error dialogs)

Here is how my static class looks like:

    public class GlobalMethods {

//To show error messages
        public static final void showSimpleAlertDialog(final Activity activity, String  message, final boolean shouldFinishActivity) {

            if (!activity.isFinishing()) {

                AlertDialog.Builder builder = new AlertDialog.Builder(activity, AlertDialog.THEME_HOLO_DARK);
                builder.setCancelable(true).setMessage("\n" + message + "\n").setNeutralButton(activity.getResources().getString(R.string.label_ok), new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        dialog.cancel();

                    }
                }).setOnCancelListener(new DialogInterface.OnCancelListener() {

                    @Override
                    public void onCancel(DialogInterface dialog) {
                        // TODO Auto-generated method stub
                        if (shouldFinishActivity)
                            activity.finish();
                    }
                }).show();
            }

        }

//check for connectivity
    public static final boolean isOnline(Context context) {
        NetworkInfo networkInfo = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();
        return (networkInfo != null && networkInfo.isConnectedOrConnecting());
    }

//for the 'HOME' button on every activity
    public static final void goToDashboard(Activity activity) {
        goToActivity(ActivityDashboard.class, activity);

    }

    }

In my main activity, I call this function like this

GlobalMethods.showSimpleAlertDialog(this, R.string.error_msg_failed_load, true);

Is this a good approach? Does this cause memory leaks? If yes, please guide me on the best practices on using utility classes

Actually, there's nothing wrong with your current code. It's true that you want to be careful when passing around `Activity` contexts, but in this scenario there are no static/long lived references that break the activity life cycle, and/or any long-running operations that may prevent a reference from being garbage collected. The summary in the link given by @agamov basically says it all. No need to clutter your code with `WeakReference` in this particular case though. — MH., Sep 18 '13 at 19:08

agamov · Accepted Answer · 2013-09-18T07:46:54.680

6

No, it's a bad approach. You better pass WeakReference<Activity> to your methods, and implement methods like this:

public static final void showSimpleAlertDialog(final WeakReference<Activity> mReference, String  message, final boolean shouldFinishActivity) {
    Activity activity = mReference.get();
    if (activity != null) {
        //your code goes here
    }

Further reading: http://android-developers.blogspot.ae/2009/01/avoiding-memory-leaks.html

edited Sep 18 '13 at 07:46

answered Sep 18 '13 at 06:28

agamov

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Thank you for the quick response, can you give an example of how WeakReference must be implemented here? – TMS Sep 18 '13 at 07:29
1

Thanks for the detailed answer! Is this the correct way to use this from Activity? globalMethods.showSimpleAlertDialog(new WeakReference(this),R.string.error_msg_failed_load, true); – TMS Sep 18 '13 at 11:38
as for me it seems ok) – agamov Sep 18 '13 at 11:56
5

This is an old question/answer, but I wanted to add my 2 cents: I think, in the case of a static method, unless you are holding the reference beyond the scope of the method itself (passing the reference to another class that stores that reference in a static member variable, for instance), WeakReference is not necessary. – jkane001 Apr 12 '16 at 16:34
The question is an old one, but the search engine still gives as a result, which means it is always good to update the stuff with the new thoughts based on the practice which we get during the years. – X-HuMan May 31 '16 at 17:19
@jkane001 I was thinking about the same thing. Unless its the case you mentioned, what's the advantage of passing a weak reference to the util class method? – Shobhit Puri Aug 06 '17 at 23:43

Passing reference to activity to utility class android

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