Alternative to setAlpha in api level 8

Question

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 a         


        

Answer 1

Also, If you want use PageTransformer even in 2.2. You must change some validation that are made in the ViewPager class. Check out this example

Answer 2

The easiest solution is to use the NineOldAndroids library, which backports the animations to all versions of Android. The Usage section has examples of how you'd use the library.

Answer 3

To be both forward and backward compatible I use following implementation for my views:

private void fadeOut(final View view) {
    int sdk = android.os.Build.VERSION.SDK_INT;
    if(sdk < android.os.Build.VERSION_CODES.JELLY_BEAN) {
        AlphaAnimation alpha = new AlphaAnimation(1f, 0f);
        alpha.setDuration(mAnimationDuration);
        alpha.setFillAfter(true);
        view.startAnimation(alpha);
    } else {
        view.animate()
        .alpha(0f)
        .setDuration(mAnimationDuration)
        .setListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                view.setVisibility(View.GONE);
            }
        });
    }
}

private void fadeIn(View view) {
    int sdk = android.os.Build.VERSION.SDK_INT;
    if(sdk < android.os.Build.VERSION_CODES.JELLY_BEAN) {
        view.setVisibility(View.VISIBLE);
        AlphaAnimation alpha = new AlphaAnimation(0f, 1f);
        alpha.setDuration(mAnimationDuration);
        alpha.setFillAfter(true);
        view.startAnimation(alpha);
    } else {
        view.setAlpha(0f);
        view.setVisibility(View.VISIBLE);

        view.animate()
        .alpha(1f)
        .setDuration(mAnimationDuration)
        .setListener(null);
    }
}

Answer 4

In case anyone is cough lazy and wants the ZoomOutPageTransformer compatible back to API 8. Uses nineoldandroids and the ViewHelper class.

package com.weddingwire.vendorsearch.Animation;

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

import com.nineoldandroids.view.ViewHelper;

public class ZoomOutPageTransformer implements ViewPager.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) { // [-Infinity,-1)
            // This page is way off-screen to the left.
            ViewHelper.setAlpha(view, 0);

        } else if (position <= 1) { // [-1,1]
            // Modify the default slide transition to shrink the page as well
            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) {
                ViewHelper.setTranslationX(view, (horzMargin - vertMargin / 2));
            } else {
                ViewHelper.setTranslationX(view, -horzMargin + vertMargin / 2);
            }

            // Scale the page down (between MIN_SCALE and 1)
            ViewHelper.setScaleX(view, scaleFactor);
            ViewHelper.setScaleY(view, scaleFactor);

            // Fade the page relative to its size.
            ViewHelper.setAlpha(view, MIN_ALPHA +
                    (scaleFactor - MIN_SCALE) /
                            (1 - MIN_SCALE) * (1 - MIN_ALPHA));

        } else { // (1,+Infinity]
            // This page is way off-screen to the right.
            ViewHelper.setAlpha(view, 0);
        }
    }
}

Answer 5

so, some resolutions here:

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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);

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

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

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setAlpha FLOAT -> API Level 11+ ->

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