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Commit 8aacfb80 authored by Jorim Jaggi's avatar Jorim Jaggi Committed by Android (Google) Code Review
Browse files

Merge "Improve logic when flinging up."

parents 05b7e2c6 efbd7e3b

packages/SystemUI/src/com/android/systemui/statusbar/FlingAnimationUtils.java

+26 −5
Original line number Diff line number Diff line
@@ -28,33 +28,35 @@ import android.view.animation.PathInterpolator; 
public class FlingAnimationUtils {



    private static final float LINEAR_OUT_SLOW_IN_X2 = 0.35f;

    private static final float LINEAR_OUT_FASTER_IN_Y2 = 0.7f;

    private static final float LINEAR_OUT_FASTER_IN_Y2_MIN = 0.7f;

    private static final float LINEAR_OUT_FASTER_IN_Y2_MAX = 1f;

    private static final float MIN_VELOCITY_DP_PER_SECOND = 250;

    private static final float HIGH_VELOCITY_DP_PER_SECOND = 3000;



    /**

     * Crazy math. http://en.wikipedia.org/wiki/B%C3%A9zier_curve

     */

    private static final float LINEAR_OUT_SLOW_IN_START_GRADIENT = 1.0f / LINEAR_OUT_SLOW_IN_X2;

    private static final float LINEAR_OUT_FASTER_IN_START_GRADIENT = LINEAR_OUT_FASTER_IN_Y2;



    private Interpolator mLinearOutSlowIn;

    private Interpolator mFastOutSlowIn;

    private Interpolator mFastOutLinearIn;

    private Interpolator mLinearOutFasterIn;



    private float mMinVelocityPxPerSecond;

    private float mMaxLengthSeconds;

    private float mHighVelocityPxPerSecond;



    public FlingAnimationUtils(Context ctx, float maxLengthSeconds) {

        mMaxLengthSeconds = maxLengthSeconds;

        mLinearOutSlowIn = new PathInterpolator(0, 0, LINEAR_OUT_SLOW_IN_X2, 1);

        mLinearOutFasterIn = new PathInterpolator(0, 0, 1, LINEAR_OUT_FASTER_IN_Y2);

        mFastOutSlowIn

                = AnimationUtils.loadInterpolator(ctx, android.R.interpolator.fast_out_slow_in);

        mFastOutLinearIn

                = AnimationUtils.loadInterpolator(ctx, android.R.interpolator.fast_out_linear_in);

        mMinVelocityPxPerSecond

                = MIN_VELOCITY_DP_PER_SECOND * ctx.getResources().getDisplayMetrics().density;

        mHighVelocityPxPerSecond

                = HIGH_VELOCITY_DP_PER_SECOND * ctx.getResources().getDisplayMetrics().density;

    }



    /**
@@ -126,7 +128,12 @@ public class FlingAnimationUtils { 
                * Math.pow(Math.abs(endValue - currValue) / maxDistance, 0.5f));

        float diff = Math.abs(endValue - currValue);

        float velAbs = Math.abs(velocity);

        float durationSeconds = LINEAR_OUT_FASTER_IN_START_GRADIENT * diff / velAbs;

        float y2 = calculateLinearOutFasterInY2(velAbs);



        // The gradient at the start of the curve is just y2.

        float startGradient = y2;

        Interpolator mLinearOutFasterIn = new PathInterpolator(0, 0, 1, y2);

        float durationSeconds = startGradient * diff / velAbs;

        if (durationSeconds <= maxLengthSeconds) {

            animator.setInterpolator(mLinearOutFasterIn);

        } else if (velAbs >= mMinVelocityPxPerSecond) {
@@ -148,6 +155,20 @@ public class FlingAnimationUtils { 
        animator.setDuration((long) (durationSeconds * 1000));

    }



    /**

     * Calculates the y2 control point for a linear-out-faster-in path interpolator depending on the

     * velocity. The faster the velocity, the more "linear" the interpolator gets.

     *

     * @param velocity the velocity of the gesture.

     * @return the y2 control point for a cubic bezier path interpolator

     */

    private float calculateLinearOutFasterInY2(float velocity) {

        float t = (velocity - mMinVelocityPxPerSecond)

                / (mHighVelocityPxPerSecond - mMinVelocityPxPerSecond);

        t = Math.max(0, Math.min(1, t));

        return (1 - t) * LINEAR_OUT_FASTER_IN_Y2_MIN + t * LINEAR_OUT_FASTER_IN_Y2_MAX;

    }



    /**

     * @return the minimum velocity a gesture needs to have to be considered a fling

     */