Change View Color with alpha animation

Question

Change View Color with alpha animation

I am writing an code where need to modified view background from one color to other color along alpha animation.

I tried with

ObjectAnimator backgroundColorAnimator = ObjectAnimator.ofObject(stickyLayout,
                        "backgroundColor",
                        new ArgbEvaluator(),
                        0xFFFFFFFF,
                        0xff78c5f9);

EDIT: Since most of us not clear, Assume we need to change this color with alpha on seekbar updated values above mentioned solution work somewhat but not as expected with alpha...any suggestion?

android

android-animation

background-color

asked on Stack Overflow Jan 5, 2015 by

CoDe • edited Mar 21, 2015 by

Adrian Cid Almaguer

6 Answers

ValueAnimator colorAnim = ObjectAnimator.ofInt(**myView**, "backgroundColor", Color.RED, Color.BLUE);
colorAnim.setDuration(3000);
colorAnim.setEvaluator(new ArgbEvaluator());
colorAnim.setRepeatCount(ValueAnimator.INFINITE);
colorAnim.setRepeatMode(ValueAnimator.REVERSE);
colorAnim.start();

Where myView is the view on which you want to apply Animation

answered on Stack Overflow Mar 25, 2015 by

Divyang Panchal • edited Nov 11, 2015 by

Kyslik

You don't really need these methods: initHeaderColor & translateHeaderView.

Define an ArgbEvaluator as a class member:

ArgbEvaluator mArgbEvaluator;

// define start & end colors
int mStartColor, mEndColor;

// initialize start & end colors

Call ArgbEvaluator's evaluate method with parameters (slideOffset, startColor, endColor), cast the return value to Integer, and use it to set the background color of fmActionBar:

void updateActionBarbgColor(float slideOffset) {
    if (mArgbEvaluator == null)
        mArgbEvaluator = new ArgbEvaluator();

    int bgColor = (Integer) mArgbEvaluator.evaluate(slideOffset, mStartColor, mEndColor);
    fmActionBar.setBackgroundColor(bgColor);
}

For reference, ArgbEvaluator#evaluate(...):

public Object evaluate(float fraction, Object startValue, Object endValue) {
    int startInt = (Integer) startValue;
    int startA = (startInt >> 24) & 0xff;
    int startR = (startInt >> 16) & 0xff;
    int startG = (startInt >> 8) & 0xff;
    int startB = startInt & 0xff;

    int endInt = (Integer) endValue;
    int endA = (endInt >> 24) & 0xff;
    int endR = (endInt >> 16) & 0xff;
    int endG = (endInt >> 8) & 0xff;
    int endB = endInt & 0xff;

    return (int)((startA + (int)(fraction * (endA - startA))) << 24) |
            (int)((startR + (int)(fraction * (endR - startR))) << 16) |
            (int)((startG + (int)(fraction * (endG - startG))) << 8) |
            (int)((startB + (int)(fraction * (endB - startB))));
}

answered on Stack Overflow Mar 20, 2015 by

Vikram

You can use different evaluator or animate alpha independently with AnimatorSet.

answered on Stack Overflow Jan 5, 2015 by

Bracadabra

This is working code I found so far:

    /**
     * Initialise header color while translate animation
     */
    private void initHeaderColor(int startColor, int endColor) {

        initR = Color.red(startColor);
        initG = Color.green(startColor);
        initB = Color.blue(startColor);
        initAlpha = Color.alpha(startColor);

        endR = Color.red(endColor);
        endG = Color.green(endColor);
        endB = Color.blue(endColor);
        endAlpha = Color.alpha(endColor);
    }

and set offset of your wish.

   /**
     * Translate header view component
     * @param slideOffset
     */
    private void translateHeaderView(float slideOffset) {

            finalR = (int) (initR + (endR - initR) * slideOffset);
            finalG = (int) (initG + (endG - initG) * slideOffset);
            finalB = (int) (initB + (endB - initB) * slideOffset);
            finalAlpha = (int) (initAlpha + (endAlpha - initAlpha) * slideOffset);

            int color = Color.argb(finalAlpha, finalR, finalG, finalB);
            fmActionBar.setBackgroundColor(color);
        }

answered on Stack Overflow Mar 20, 2015 by

CoDe

I use an static helper Method to interpolate two colors.

public static int interpolateColor(int colorA, int colorB, float proportion) {
float[] hsva = new float[3];
float[] hsvb = new float[3];
Color.colorToHSV(colorA, hsva);
Color.colorToHSV(colorB, hsvb);
for (int i = 0; i < 3; i++) {
  hsvb[i] = interpolate(hsva[i], hsvb[i], proportion);
}
int alpha1 = Color.alpha(colorA);
int alpha2 = Color.alpha(colorB);
int newAlpha = interpolate(alpha1, alpha2, proportion);
return Color.HSVToColor(newAlpha, hsvb);  }

Also the interpolate Method:

private static float interpolate(float a, float b, float proportion) {
return (a + ((b - a) * proportion)); }

This method gives the correct color for a proportion value betwenn 0-1 where 0 is colorA is fully visible and 1 means colorB is fully visible.

You then can use a ValueAnimator add an onUpdateListener and get the animationPercentage and pass it as proportion to the interpolate Method.

As you can see i added the alpha values into the method aswell.

answered on Stack Overflow Mar 20, 2015 by

Lukas Olsen • edited Mar 20, 2015 by

Lukas Olsen

Use Color.parseColor instead of directly 0x value. Code example in Kotlin though

val objectAnimator = ObjectAnimator.ofObject(my_2_text, "backgroundColor",  ArgbEvaluator(),
    Color.parseColor("#FFFFFFFF"), Color.parseColor("#FF78c5f9"))

answered on Stack Overflow May 30, 2020 by

Elye

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