Merge "VelocityTracker API Documentation Improvements" (16c0e892) · Commits · e / os / android_frameworks_base

core/java/android/view/VelocityTracker.java

+22 −8

Original line number	Diff line number	Diff line
		@@ -28,7 +28,7 @@ import java.lang.annotation.RetentionPolicy;
		import java.util.Map;

		/**
		* Helper for tracking the velocity of touch events, for implementing
		* Helper for tracking the velocity of motion events, for implementing
		* flinging and other such gestures.
		*
		* Use {@link #obtain} to retrieve a new instance of the class when you are going
		@@ -43,6 +43,15 @@ public final class VelocityTracker {

		private static final int ACTIVE_POINTER_ID = -1;

		/** @hide */
		@IntDef(value = {
		MotionEvent.AXIS_X,
		MotionEvent.AXIS_Y,
		MotionEvent.AXIS_SCROLL
		})
		@Retention(RetentionPolicy.SOURCE)
		public @interface VelocityTrackableMotionEventAxis {}

		/**
		* Velocity Tracker Strategy: Invalid.
		*
		@@ -306,10 +315,12 @@ public final class VelocityTracker {
		}

		/**
		* Checks whether a given motion axis is supported for velocity tracking.
		* Checks whether a given velocity-trackable {@link MotionEvent} axis is supported for velocity
		* tracking by this {@link VelocityTracker} instance (refer to
		* {@link #getAxisVelocity(int, int)} for a list of potentially velocity-trackable axes).
		*
		* <p>The axis values that would make sense to use for this method are the ones defined in the
		* {@link MotionEvent} class.
		* <p>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 {@link VelocityTracker} instance.
		*
		* @param axis The axis to check for velocity support.
		* @return {@code true} if {@code axis} is supported for velocity tracking, or {@code false}
		@@ -317,7 +328,7 @@ public final class VelocityTracker {
		* @see #getAxisVelocity(int, int)
		* @see #getAxisVelocity(int)
		*/
		public boolean isAxisSupported(int axis) {
		public boolean isAxisSupported(@VelocityTrackableMotionEventAxis int axis) {
		return nativeIsAxisSupported(axis);
		}

		@@ -421,13 +432,16 @@ public final class VelocityTracker {
		* calling this function.
		*
		* <p>In addition to {@link MotionEvent#AXIS_X} and {@link MotionEvent#AXIS_Y} which have been
		* supported since the introduction of this class, the following axes are supported for this
		* supported since the introduction of this class, the following axes can be candidates for this
		* method:
		* <ul>
		* <li> {@link MotionEvent#AXIS_SCROLL}: supported starting
		* {@link Build.VERSION_CODES#UPSIDE_DOWN_CAKE}
		* </ul>
		*
		* <p>Before accessing velocities of an axis using this method, check that your
		* {@link VelocityTracker} instance supports the axis by using {@link #isAxisSupported(int)}.
		*
		* @param axis Which axis' velocity to return.
		* @param id Which pointer's velocity to return.
		* @return The previously computed velocity for {@code axis} for pointer ID of {@code id} if
		@@ -435,7 +449,7 @@ public final class VelocityTracker {
		* for the axis.
		* @see #isAxisSupported(int)
		*/
		public float getAxisVelocity(int axis, int id) {
		public float getAxisVelocity(@VelocityTrackableMotionEventAxis int axis, int id) {
		return nativeGetVelocity(mPtr, axis, id);
		}

		@@ -450,7 +464,7 @@ public final class VelocityTracker {
		* @see #isAxisSupported(int)
		* @see #getAxisVelocity(int, int)
		*/
		public float getAxisVelocity(int axis) {
		public float getAxisVelocity(@VelocityTrackableMotionEventAxis int axis) {
		return nativeGetVelocity(mPtr, axis, ACTIVE_POINTER_ID);
		}