具有给定速度的动画？

Question

I am using a VelocityTracker to find out the velocity of a MotionEvent in the onTouch method. After the MotionEvent is finished, I want to start an animation (translate a view) with the velocity detected prior and then accelerate/deaccelerate.

To make clear: I'm not asking about duration , i want an animation that starts with a given velocity .

Answer 1

You will need to implement your own Interpolator that takes a start velocity and interpolates values from there. getInterpolation() is the method you want to override to provide your own interpolation, and the documentation there describes what different return values mean.

In a nutshell, the input is how far along (from 0f to 1f) you are in time, and the output is how far along you want your View to be in its animation.

You will have to do a bit of calculation when creating your interpolator to determine the appropriate return values to respect the initial velocity.

For reference, I would start by looking at the source for the stock AccelerateInterpolator