Handlers and memory leaks in Android

Question

Please have a look at the code below:

public class MyGridFragment extends Fragment{

     Handler myhandler = new Handler() {
    @Override
    public void handleMessage(Message message) {
        switch (message.what) {
        case 2: {

            ArrayList<HashMap<String,String>> theurls = (ArrayList<HashMap<String,String>>) message.obj;
            urls.addAll(theurls);
            theimageAdapter.notifyDataSetChanged();
            dismissBusyDialog();
            break;
        }}}};
         }

When I use handler like this I get a warning "handler should be static, else it is prone to memory leaks." Can someone tell me what is the best way to do this?

Answer 1

I recently updated something similar in my own code. I just made the anonymous Handler class a protected inner class and the Lint warning went away. See if something like the below code will work for you:

public class MyGridFragment extends Fragment{

    static class MyInnerHandler extends Handler{
        WeakReference<MyGridFragment> mFrag;

        MyInnerHandler(MyGridFragment aFragment) {
            mFrag = new WeakReference<MyGridFragment>(aFragment);
        }

        @Override
        public void handleMessage(Message message) {
            MyGridFragment theFrag = mFrag.get();
            switch (message.what) {
            case 2:
                ArrayList<HashMap<String,String>> theurls = (ArrayList<HashMap<String,String>>) message.obj;
                theFrag.urls.addAll(theurls);
                theFrag.theimageAdapter.notifyDataSetChanged();
                theFrag.dismissBusyDialog();
                break;
            }//end switch
        }
    }
    MyInnerHandler myHandler = new MyInnerHandler(this);
}

You may have to change where I put "theFrag." as I could only guess as to what those referenced.