Play predictive animation when quickly restarting back gesture after cancel

import android.view.RemoteAnimationTarget;

import android.view.SurfaceControl;

import android.view.View;

import android.view.animation.AnimationUtils;

import android.view.animation.DecelerateInterpolator;

import android.view.animation.Interpolator;

import android.window.BackEvent;

 *

 */

public class LauncherBackAnimationController {

    private static final int CANCEL_TRANSITION_DURATION = 233;

    private static final int SCRIM_FADE_DURATION = 233;

    private static final float MIN_WINDOW_SCALE = 0.85f;

    private static final float MAX_SCRIM_ALPHA_DARK = 0.8f;

    private final Matrix mTransformMatrix = new Matrix();

    /** The window position at the beginning of the back animation. */

    private final Rect mStartRect = new Rect();

    /** The window position when the back gesture is cancelled. */

    private final RectF mCancelRect = new RectF();

    /** The current window position. */

    private final RectF mCurrentRect = new RectF();

    private final QuickstepLauncher mLauncher;

    private final int mWindowScaleMarginX;

    private float mWindowScaleEndCornerRadius;

    private float mWindowScaleStartCornerRadius;

    private final Interpolator mCancelInterpolator;

    private final Interpolator mProgressInterpolator = Interpolators.STANDARD_DECELERATE;

    private final Interpolator mVerticalMoveInterpolator = new DecelerateInterpolator();

    private final PointF mInitialTouchPos = new PointF();

        loadCornerRadius();

        mWindowScaleMarginX = mLauncher.getResources().getDimensionPixelSize(

                R.dimen.swipe_back_window_scale_x_margin);

        mCancelInterpolator =

                AnimationUtils.loadInterpolator(mLauncher, R.interpolator.standard_interpolator);

    }

    /**

            mHandler.post(() -> {

                LauncherBackAnimationController controller = mControllerRef.get();

                if (controller != null) {

                    mProgressAnimator.onBackCancelled(

                            controller::resetPositionAnimated);

                    mProgressAnimator.onBackCancelled(controller::onCancelFinished);

                }

            });

        }

        public void onAnimationCancelled() {}

    }

    private void resetPositionAnimated() {

        ValueAnimator cancelAnimator = ValueAnimator.ofFloat(0, 1);

        mCancelRect.set(mCurrentRect);

        cancelAnimator.setDuration(CANCEL_TRANSITION_DURATION);

        cancelAnimator.setInterpolator(mCancelInterpolator);

        cancelAnimator.addUpdateListener(

                animation -> {

                    updateCancelProgress((float) animation.getAnimatedValue());

                });

        cancelAnimator.addListener(new AnimatorListenerAdapter() {

            @Override

            public void onAnimationEnd(Animator animation) {

                // Refresh the status bar appearance to the original one.

    private void onCancelFinished() {

        customizeStatusBarAppearance(false);

        finishAnimation();

    }

        });

        cancelAnimator.start();

    }

    /** Unregisters the back to launcher callback in shell. */

    public void unregisterBackCallbacks() {

    }

    private void startBack(BackMotionEvent backEvent) {

        // in case we're still animating an onBackCancelled event, let's remove the finish-

        // callback from the progress animator to prevent calling finishAnimation() before

        // restarting a new animation

        // Side note: startBack is never called during the post-commit phase if the back gesture

        // was committed (not cancelled). BackAnimationController prevents that. Therefore we

        // don't have to handle that case.

        mProgressAnimator.removeOnBackCancelledFinishCallback();

        mBackInProgress = true;

        RemoteAnimationTarget appTarget = backEvent.getDepartingAnimationTarget();

                new RemoteAnimationTarget[]{ mBackTarget });

        setLauncherTargetViewVisible(false);

        mCurrentRect.set(mStartRect);

        if (mScrimLayer == null) {

            addScrimLayer();

        }

        mTransaction.apply();

    }

        customizeStatusBarAppearance(progress > UPDATE_SYSUI_FLAGS_THRESHOLD);

    }

    private void updateCancelProgress(float progress) {

        if (mBackTarget == null) {

            return;

        }

        mCurrentRect.set(

                Utilities.mapRange(progress, mCancelRect.left, mStartRect.left),

                Utilities.mapRange(progress, mCancelRect.top, mStartRect.top),

                Utilities.mapRange(progress, mCancelRect.right, mStartRect.right),

                Utilities.mapRange(progress, mCancelRect.bottom, mStartRect.bottom));

        float endCornerRadius = Utilities.mapRange(

                mBackProgress, mWindowScaleStartCornerRadius, mWindowScaleEndCornerRadius);

        float cornerRadius = Utilities.mapRange(

                progress, endCornerRadius, mWindowScaleStartCornerRadius);

        applyTransform(mCurrentRect, cornerRadius);

    }

    /** Transform the target window to match the target rect. */

    private void applyTransform(RectF targetRect, float cornerRadius) {

        final float scale = targetRect.width() / mStartRect.width();

        mBackInProgress = false;

        mBackProgress = 0;

        mTransformMatrix.reset();

        mCancelRect.setEmpty();

        mCurrentRect.setEmpty();

        mStartRect.setEmpty();

        mInitialTouchPos.set(0, 0);