Optimized ImageView

gistfile1.txt

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.util.AttributeSet;
import android.widget.ImageView;

/**
 * 
 * ImageView using the optimization from Jelly Bean.
 * 
 * @author Viktor Nyblom
 * 
 */
public class OptimizedImageView extends ImageView {

  private boolean mIgnoreNextRequestLayout = false;

	public OptimizedImageView(Context context) {
		super(context);
	}

	public OptimizedImageView(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

	public OptimizedImageView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
	}

	@Override
	public void setImageDrawable(final Drawable newDrawable) {
		if (VERSION.SDK_INT < VERSION_CODES.JELLY_BEAN_MR1) {

			// The currently set Drawable
			final Drawable oldDrawable = getDrawable();

			if (null != oldDrawable && oldDrawable != newDrawable) {
				final int oldWidth = oldDrawable.getIntrinsicWidth();
				final int oldHeight = oldDrawable.getIntrinsicHeight();

				/**
				 * Ignore the next requestLayout call if the new Drawable is the
				 * same size as the currently displayed one.
				 * */
				mIgnoreNextRequestLayout = oldHeight == newDrawable
						.getIntrinsicHeight()
						&& oldWidth == newDrawable.getIntrinsicWidth();
			}
		}

		// Finally, call up to super
		super.setImageDrawable(newDrawable);
	}

	@Override
	public void requestLayout() {
		if (!mIgnoreNextRequestLayout) {
			super.requestLayout();
		}

		// Reset Flag so that the requestLayout() will work again
		mIgnoreNextRequestLayout = false;
	}

}