CODEWITHSUNDEEP
androidtranslate-animation
user2687482
user2687482

Reputation: 215

Android ValueAnimator Sin wave

I've got a Custom ViewGroup class and an image I've added to it. When the screen is tapped I want to animate the added image to travel across the screen in a wavelike pattern. What I have now is below but though the image moves in a wavelike pattern it jumps around too quickly and is a blur. How can I slow it down to move in a steady wave?

    ValueAnimator animator = ValueAnimator.ofFloat(0, 1); // values from 0 to 1
    if(animateImage) {
        incrementalValue = 0f;
        animator.setDuration(4000);
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                float value = ((Float) (animation.getAnimatedValue()))
                        .floatValue();
                float amplitude = 100f;
                mImage.setTranslationX(incrementalValue);
                mImage.setTranslationY((float) (amplitude * Math.sin((incrementalValue) * Math.PI)));
                 incrementalValue += 5f;
            }
        });
        animator.setTarget(mImage);
        animator.start();
    }

Upvotes: 1

Views: 2096

Answers (1)

Gumbo
Gumbo

Reputation: 1746

You declare a float value in onAnimationUpdate and never use it again. The calcualtion for the image translation is mImage.setTranslationY((float) (amplitude * Math.sin((incrementalValue) * Math.PI)));. If you insert the values and incrementalValue ( = 0) doesn't change, this calculation will always return 0 because sin(0) = 0 and one 0 in a multiplication makes the product 0. You should insert animator.getAnimatedValue for incrementalValue. Besides, i suggest you change the calculation to sin(animator.getAnimatedValue()*PI*2) this makes the wavelength of the sine 1sin(x*pi*2) and the image will move up and down once per repetition of the animation and it won't jump when the aimation restarts.

Note you can still multiply with amplitude to make the image move a certain distance.

Upvotes: 2

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