Question

Here is my code

public void invalidateWidget(boolean invalidateUsingCaches) {
        mUpdatingWidget = true;

        if (invalidateUsingCaches) {
            widget.invalidateUsingCaches();
            if (widget.isRefreshRequired()) {
                widget.initializeRefreshRequired();
                mWidgetUpdateHandler.removeMessages(handlerMessage);
                mWidgetUpdateHandler.sendEmptyMessageDelayed(handlerMessage,
                        handlerDelay);
            }
        } else {
            widget.invalidate(false);
        }

        refreshImageView();

        mUpdatingWidget = false;
    }

This line

mWidgetUpdateHandler.sendEmptyMessageDelayed(handlerMessage,
                        handlerDelay); 

causes imageview to not update with changes on phones with android versions 2.3 but works on newer android versions.

So far I have tried the following:

1. imageview.invalidate();
2. used a runnable with handler.
3. activity.runOnUiThread();

Remember the code works on newer android versions. Well it should work on all versions as the code follows Android guidelines.

Does anybody has a clue why this should be happenning? Solution?
Is MessageQueue has something to do here?

Answer 1

The problem was with supplying new bitmap to imageview. In handler’s handleMessage() I was giving new bitmap to the imageview which caused it to not refresh with changes. The handler worked fine. Though I still don’t understand why imageview refused new bitmap on old android versions.

I solved the problem by keeping the same bitmap.