Alternative to setAlpha in api level 8

Chintan Soni picture Chintan Soni · May 26, 2013 · Viewed 16.4k times · Source

I am working on an app, which can run on Froyo as well as JellyBean. I have a class that extends PageTransformer as below:

import android.support.v4.view.ViewPager.PageTransformer;
import android.view.View;

public class ZoomOutPageTransformer implements PageTransformer {
    private static float MIN_SCALE = 0.85f;
    private static float MIN_ALPHA = 0.5f;

    public void transformPage(View view, float position) {
        int pageWidth = view.getWidth();
        int pageHeight = view.getHeight();

        if (position < -1) { 
            view.setAlpha(0);

        } else if (position <= 1) { 
            float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
            float vertMargin = pageHeight * (1 - scaleFactor) / 2;
            float horzMargin = pageWidth * (1 - scaleFactor) / 2;
            if (position < 0) {
                view.setTranslationX(horzMargin - vertMargin / 2);
            } else {
                view.setTranslationX(-horzMargin + vertMargin / 2);
            }


            view.setScaleX(scaleFactor);
            view.setScaleY(scaleFactor);


            view.setAlpha(MIN_ALPHA +
                    (scaleFactor - MIN_SCALE) /
                    (1 - MIN_SCALE) * (1 - MIN_ALPHA));

        } else { 
            view.setAlpha(0);
        }
    }
}

The problem is, the methods written in this class were added in API level 11 and i have minimum sdk version of API level 8. The following are those methods that were added in API level 11:

  1. setAlpha()
  2. setTranslationX()
  3. setScaleX()
  4. setScaleY()

What can be the solution for this problem ?

Answer

cV2 picture cV2 · Sep 25, 2013

so, some resolutions here:


setAlphaAnimation … API LEVEL 1

AlphaAnimation alpha = new AlphaAnimation(0.7F, 0.7F);
alpha.setDuration(0); // Make animation instant
alpha.setFillAfter(true); // Tell it to persist after the animation ends
view.startAnimation(alpha);

setAlpha INT -> From API LEVEL 1 -> deprecated in 16

Drawable background = localLinLayout.getBackground();
background.setAlpha(180); //255 is max (visible)

setAlpha FLOAT -> API Level 11+ ->


setImageAlpha -> API LEVEL 16+ (use just for ImageViews)