VelocityTrackerCompat

java-static fun addMovement(tracker: VelocityTracker, event: MotionEvent): Unit

Add a user's movement to the tracker.

For pointer events, you should call this for the initial ACTION_DOWN, the following ACTION_MOVE events that you receive, and the final ACTION_UP. You can, however, call this for whichever events you desire.

java-static fun clear(tracker: VelocityTracker): Unit

Reset the velocity tracker back to its initial state.

java-static fun computeCurrentVelocity(tracker: VelocityTracker, units: Int): Unit

Equivalent to invoking computeCurrentVelocity with a maximum velocity of Float.MAX_VALUE.

java-static fun computeCurrentVelocity(
    tracker: VelocityTracker,
    units: Int,
    maxVelocity: Float
): Unit

Compute the current velocity based on the points that have been collected. Only call this when you actually want to retrieve velocity information, as it is relatively expensive. You can then retrieve the velocity with getAxisVelocity ()}.

java-static fun getAxisVelocity(tracker: VelocityTracker, axis: Int): Float

Equivalent to calling getAxisVelocity for axis and the active pointer.

java-static fun getAxisVelocity(tracker: VelocityTracker, axis: Int, pointerId: Int): Float

Retrieve the last computed velocity for a given motion axis. You must first call computeCurrentVelocity or computeCurrentVelocity before calling this function.

In addition to AXIS_X and AXIS_Y which have been supported since the introduction of this class, the following axes can be candidates for this method:

• AXIS_SCROLL: supported via the platform starting UPSIDE_DOWN_CAKE. Supported via a fallback logic at all platform levels for the active pointer only.

Before accessing velocities of an axis using this method, check that your VelocityTracker instance supports the axis by using isAxisSupported.

@ReplaceWith(expression = "tracker.getXVelocity(pointerId)")
java-static fun getXVelocity(tracker: VelocityTracker!, pointerId: Int): Float

Call getXVelocity. If running on a pre-HONEYCOMB device, returns getXVelocity.

@ReplaceWith(expression = "tracker.getYVelocity(pointerId)")
java-static fun getYVelocity(tracker: VelocityTracker!, pointerId: Int): Float

Call getYVelocity. If running on a pre-HONEYCOMB device, returns getYVelocity.

java-static fun isAxisSupported(tracker: VelocityTracker, axis: Int): Boolean

Checks whether a given velocity-trackable MotionEvent axis is supported for velocity tracking by this VelocityTracker instance (refer to getAxisVelocity for a list of potentially velocity-trackable axes).

Note that the value returned from this method will stay the same for a given instance, so a single check for axis support is enough per a VelocityTracker instance.

java-static fun recycle(tracker: VelocityTracker): Unit

Return a VelocityTracker object back to be re-used by others.

Call this method for your VelocityTracker when you have finished tracking velocity for the use-case you created this tracker for and decided that you no longer need it. This allows it to be returned back to the pool of trackers to be re-used by others.

You must not touch the object after calling this function. That is, don't call any methods on it, or pass it as an input to any of this class' compat APIs, as the instance is no longer valid for velocity tracking.