memory - java.lang.OutOfMemoryError: bitmap size exceeds VM budget - android - how many images?

Question

I am developing an android app and as I read all around and learned for myself, I cant have a lot of images on the screen at the same time or I will get an exception.

The question is how many images or how many KB in images or how many layouts/images can I have at the same time in the screen.

I know this is not the only thing that has influence on memory, but I am looking for a number so I can plan around it.

Thanks

Daniel

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Edit:

I just found this on the android dev site (http://developer.android.com/resources/articles/future-proofing.html)

Technique to Avoid, #3: Going Overboard with Layouts

Due to changes in the View rendering infrastructure, unreasonably deep (more than 10 or so) or broad (more than 30 total) View hierarchies in layouts are now likely to cause crashes. This was always a risk for excessively complex layouts, but you can think of Android 1.5 as being better than 1.1 at exposing this problem. Most developers won't need to worry about this, but if your app has very complicated layouts, you'll need to put it on a diet. You can simplify your layouts using the more advanced layout classes like FrameLayout and TableLayout.

I guess this can be my problem.

When it says 'broad' , is it saying on the last level ?

Thanks

Daniel

Answer 1

One of the most common errors that I found developing Android Apps is the

java.lang.OutOfMemoryError: Bitmap Size Exceeds VM Budget error.

I found this error frequently on activities using lots of bitmaps after changing orientation: the Activity is destroyed, created again and the layouts are “inflated” from the XML consuming the VM memory available for bitmaps.

Bitmaps on the previous activity layout are not properly deallocated by the garbage collector because they have crossed references to their activity. After many experiments I found a quite good solution for this problem.

First, set the id attribute on the parent view of your XML layout:

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:id="@+id/RootView"
     >
     ...

Then, on the onDestroy() method of your Activity, call the unbindDrawables() method passing a refence to the parent View and then do a System.gc()

    @Override
    protected void onDestroy() {
    super.onDestroy();

    unbindDrawables(findViewById(R.id.RootView));
    System.gc();
    }

    private void unbindDrawables(View view) {
        if (view.getBackground() != null) {
        view.getBackground().setCallback(null);
        }
        if (view instanceof ViewGroup) {
            for (int i = 0; i < ((ViewGroup) view).getChildCount(); i++) {
            unbindDrawables(((ViewGroup) view).getChildAt(i));
            }
        ((ViewGroup) view).removeAllViews();
        }
    }

This unbindDrawables() method explores the view tree recursively and:

• Removes callbacks on all the background drawables
• Removes childs on every viewgroup