CODEWITHSUNDEEP
androidandroid-studio
Varun Gawande
Varun Gawande

Reputation: 1120

How to give a RotationAnimation a steady speed?

In my Android app, I have a fan image whose rotation speed is set by regulator.
This is the animation part:

    private fun setFanSpeed(toggle:Boolean, speed:Float){
        var speed:Float = speed
        if (!toggle)
            speed = 0F
        val animation = RotateAnimation(0F, 720F,
            Animation.RELATIVE_TO_SELF,0.5f,
            Animation.RELATIVE_TO_SELF, 0.5f
        )
        animation.duration = speedToDuration(speed)*1000
        animation.repeatCount = Animation.INFINITE
        fan.animation = animation
        fan.startAnimation(animation)
    }

Unfortunately, the rotating fan feels weird because, instead of rotating at a constant speed i.e 720 rotation in a constant time it accelerates during the start of the animation, and decelerates to a stop during the end. Then speeds up again for the next rotation.

How can I remove the speed up and the speed down, and just make the animation work at a constant speed?

Upvotes: 0

Views: 55

Answers (1)

ardget
ardget

Reputation: 2651

It seems that AccelerateDecelerateInterpolator is the default interpolator for Animation, against the caption in documentation. Specifying LinearInterpolator explicitly, you'll be able to make it rotate uniformly.

animation.interpolator = LinearInterpolator()

Upvotes: 1

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