CODEWITHSUNDEEP
androidandroid-animation
dors
dors

Reputation: 5892

Create a DecelerateAccelerateInterpolator

Android provides the following animation interpolators: AccelerateInterpolator, DecelerateInterpolator, AccelerateDecelerateInterpolator.

How can I achieve a DecelerateAccelerateInterpolator?

Upvotes: 2

Views: 428

Answers (1)

pdegand59
pdegand59

Reputation: 13039

You want an interpolator that goes fast at the start and end but slow in the middle ?

Find the proper math function that represents your interpolator and implement the Interpolator interface with your math function.

Example from http://cogitolearning.co.uk/?p=1078

public class DecelerateAccelerateInterpolator implements Interpolator {
  public DecelerateAccelerateInterpolator() {}
  public float getInterpolation(float t) {
    float x=2.0f*t-1.0f;
    return 0.5f*(x*x*x + 1.0f);
  }
}

Or combine a DecelerateInterpolator following by and AccelerateInterpolator.

public class DecelerateAccelerateInterpolator implements Interpolator {
  final float factor;
  public DecelerateAccelerateInterpolator() {
    this(1);
  }

  public DecelerateAccelerateInterpolator(float factor) {
    this.factor = factor;
  }

  public float getInterpolation(float t) {
    if (t < 0.5f) {
      return new DecelerateInterpolator(factor).getInterpolation(2 * t);
    } else {
      return new AccelerateInterpolator(factor).getInterpolation(2 * (t - 0.5f));
    }
  }
}

Upvotes: 4

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