src/com/android/launcher3/util/VerticalSwipeController.java - platform/packages/apps/Launcher3 - Gitiles

 /*
  * Copyright (C) 2017 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package com.android.launcher3.util;

 import static com.android.launcher3.LauncherState.ALL_APPS;
 import static com.android.launcher3.anim.Interpolators.scrollInterpolatorForVelocity;
 import static com.android.launcher3.anim.SpringAnimationHandler.Y_DIRECTION;

 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.ValueAnimator;
 import android.support.animation.SpringAnimation;
 import android.util.Log;
 import android.view.MotionEvent;

 import com.android.launcher3.AbstractFloatingView;
 import com.android.launcher3.Launcher;
 import com.android.launcher3.LauncherState;
 import com.android.launcher3.Utilities;
 import com.android.launcher3.allapps.AllAppsContainerView;
 import com.android.launcher3.anim.AnimatorPlaybackController;
 import com.android.launcher3.anim.SpringAnimationHandler;
 import com.android.launcher3.touch.SwipeDetector;

 import java.util.ArrayList;

 /**
  * Handles vertical touch gesture on the DragLayer allowing transitioning from
  * {@link #mBaseState} to {@link LauncherState#ALL_APPS} and vice-versa.
  */
 public abstract class VerticalSwipeController extends AnimatorListenerAdapter
         implements TouchController, SwipeDetector.Listener {

     private static final String TAG = "VerticalSwipeController";

     private static final float RECATCH_REJECTION_FRACTION = .0875f;
     private static final int SINGLE_FRAME_MS = 16;

     // Progress after which the transition is assumed to be a success in case user does not fling
     private static final float SUCCESS_TRANSITION_PROGRESS = 0.5f;

     protected final Launcher mLauncher;
     private final SwipeDetector mDetector;
     private final LauncherState mBaseState;

     private boolean mNoIntercept;

     private AnimatorPlaybackController mCurrentAnimation;
     private LauncherState mToState;

     private float mStartProgress;
     // Ratio of transition process [0, 1] to drag displacement (px)
     private float mProgressMultiplier;

     private SpringAnimationHandler[] mSpringHandlers;

     public VerticalSwipeController(Launcher l, LauncherState baseState) {
         mLauncher = l;
         mDetector = new SwipeDetector(l, this, SwipeDetector.VERTICAL);
         mBaseState = baseState;
     }

     private boolean canInterceptTouch(MotionEvent ev) {
         if (mCurrentAnimation != null) {
             // If we are already animating from a previous state, we can intercept.
             return true;
         }
         if (AbstractFloatingView.getTopOpenView(mLauncher) != null) {
             return false;
         }
         return shouldInterceptTouch(ev);
     }

     protected abstract boolean shouldInterceptTouch(MotionEvent ev);

     @Override
     public void onAnimationCancel(Animator animation) {
         if (mCurrentAnimation != null && animation == mCurrentAnimation.getTarget()) {
             Log.e(TAG, "Who dare cancel the animation when I am in control", new Exception());
             mDetector.finishedScrolling();
             mCurrentAnimation = null;
         }
     }

     private void initSprings() {
         AllAppsContainerView appsView = mLauncher.getAppsView();

         SpringAnimationHandler handler = appsView.getSpringAnimationHandler();
         if (handler == null) {
             mSpringHandlers = new SpringAnimationHandler[0];
             return;
         }

         ArrayList<SpringAnimationHandler> handlers = new ArrayList<>();
         handlers.add(handler);

         SpringAnimation searchSpring = appsView.getSearchUiManager().getSpringForFling();
         if (searchSpring != null) {
             SpringAnimationHandler searchHandler =
                     new SpringAnimationHandler(Y_DIRECTION, handler.getFactory());
             searchHandler.add(searchSpring, true /* setDefaultValues */);
             handlers.add(searchHandler);
         }

         mSpringHandlers = handlers.toArray(new SpringAnimationHandler[handlers.size()]);
     }

     @Override
     public boolean onControllerInterceptTouchEvent(MotionEvent ev) {
         if (ev.getAction() == MotionEvent.ACTION_DOWN) {
             mNoIntercept = !canInterceptTouch(ev);
             if (mNoIntercept) {
                 return false;
             }

             // Now figure out which direction scroll events the controller will start
             // calling the callbacks.
             final int directionsToDetectScroll;
             boolean ignoreSlopWhenSettling = false;

             if (mCurrentAnimation != null) {
                 if (mCurrentAnimation.getProgressFraction() > 1 - RECATCH_REJECTION_FRACTION) {
                     directionsToDetectScroll = SwipeDetector.DIRECTION_POSITIVE;
                 } else if (mCurrentAnimation.getProgressFraction() < RECATCH_REJECTION_FRACTION ) {
                     directionsToDetectScroll = SwipeDetector.DIRECTION_NEGATIVE;
                 } else {
                     directionsToDetectScroll = SwipeDetector.DIRECTION_BOTH;
                     ignoreSlopWhenSettling = true;
                 }
             } else {
                 directionsToDetectScroll = getSwipeDirection(ev);
             }

             mDetector.setDetectableScrollConditions(
                     directionsToDetectScroll, ignoreSlopWhenSettling);

             if (mSpringHandlers == null) {
                 initSprings();
             }
         }

         if (mNoIntercept) {
             return false;
         }

         onControllerTouchEvent(ev);
         return mDetector.isDraggingOrSettling();
     }

     protected abstract int getSwipeDirection(MotionEvent ev);

     @Override
     public boolean onControllerTouchEvent(MotionEvent ev) {
         for (SpringAnimationHandler h : mSpringHandlers) {
             h.addMovement(ev);
         }
         return mDetector.onTouchEvent(ev);
     }

     @Override
     public void onDragStart(boolean start) {
         if (mCurrentAnimation == null) {
             float range = getShiftRange();
             long maxAccuracy = (long) (2 * range);

             // Build current animation
             mToState = mLauncher.isInState(ALL_APPS) ? mBaseState : ALL_APPS;
             mCurrentAnimation = mLauncher.getStateManager()
                     .createAnimationToNewWorkspace(mToState, maxAccuracy);
             mCurrentAnimation.getTarget().addListener(this);
             mStartProgress = 0;
             mProgressMultiplier = (mLauncher.isInState(ALL_APPS) ? 1 : -1) / range;
             mCurrentAnimation.dispatchOnStart();
         } else {
             mCurrentAnimation.pause();
             mStartProgress = mCurrentAnimation.getProgressFraction();
         }

         for (SpringAnimationHandler h : mSpringHandlers) {
             h.skipToEnd();
         }
     }

     private float getShiftRange() {
         return mLauncher.getAllAppsController().getShiftRange();
     }

     @Override
     public boolean onDrag(float displacement, float velocity) {
         float deltaProgress = mProgressMultiplier * displacement;
         mCurrentAnimation.setPlayFraction(deltaProgress + mStartProgress);
         return true;
     }

     @Override
     public void onDragEnd(float velocity, boolean fling) {
         final long animationDuration;
         final LauncherState targetState;
         final float progress = mCurrentAnimation.getProgressFraction();

         if (fling) {
             if (velocity < 0) {
                 targetState = ALL_APPS;
                 animationDuration = SwipeDetector.calculateDuration(velocity,
                         mToState == ALL_APPS ? (1 - progress) : progress);
             } else {
                 targetState = mBaseState;
                 animationDuration = SwipeDetector.calculateDuration(velocity,
                         mToState == ALL_APPS ? progress : (1 - progress));
             }
             // snap to top or bottom using the release velocity
         } else {
             if (progress > SUCCESS_TRANSITION_PROGRESS) {
                 targetState = mToState;
                 animationDuration = SwipeDetector.calculateDuration(velocity, 1 - progress);
             } else {
                 targetState = mToState == ALL_APPS ? mBaseState : ALL_APPS;
                 animationDuration = SwipeDetector.calculateDuration(velocity, progress);
             }
         }

         if (fling && targetState == ALL_APPS) {
             for (SpringAnimationHandler h : mSpringHandlers) {
                 // The icons are moving upwards, so we go to 0 from 1. (y-axis 1 is below 0.)
                 h.animateToFinalPosition(0 /* pos */, 1 /* startValue */);
             }
         }

         mCurrentAnimation.setEndAction(() -> {
             mLauncher.getStateManager().goToState(targetState, false);
             onTransitionComplete(fling, targetState == mToState);
             mDetector.finishedScrolling();
             mCurrentAnimation = null;
         });

         float nextFrameProgress = Utilities.boundToRange(
                 progress + velocity * SINGLE_FRAME_MS / getShiftRange(), 0f, 1f);

         ValueAnimator anim = mCurrentAnimation.getAnimationPlayer();
         anim.setFloatValues(nextFrameProgress, targetState == mToState ? 1f : 0f);
         anim.setDuration(animationDuration);
         anim.setInterpolator(scrollInterpolatorForVelocity(velocity));
         anim.start();
     }

     protected abstract void onTransitionComplete(boolean wasFling, boolean stateChanged);
 }
	/*
	* Copyright (C) 2017 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.android.launcher3.util;

	import static com.android.launcher3.LauncherState.ALL_APPS;
	import static com.android.launcher3.anim.Interpolators.scrollInterpolatorForVelocity;
	import static com.android.launcher3.anim.SpringAnimationHandler.Y_DIRECTION;

	import android.animation.Animator;
	import android.animation.AnimatorListenerAdapter;
	import android.animation.ValueAnimator;
	import android.support.animation.SpringAnimation;
	import android.util.Log;
	import android.view.MotionEvent;

	import com.android.launcher3.AbstractFloatingView;
	import com.android.launcher3.Launcher;
	import com.android.launcher3.LauncherState;
	import com.android.launcher3.Utilities;
	import com.android.launcher3.allapps.AllAppsContainerView;
	import com.android.launcher3.anim.AnimatorPlaybackController;
	import com.android.launcher3.anim.SpringAnimationHandler;
	import com.android.launcher3.touch.SwipeDetector;

	import java.util.ArrayList;

	/**
	* Handles vertical touch gesture on the DragLayer allowing transitioning from
	* {@link #mBaseState} to {@link LauncherState#ALL_APPS} and vice-versa.
	*/
	public abstract class VerticalSwipeController extends AnimatorListenerAdapter
	implements TouchController, SwipeDetector.Listener {

	private static final String TAG = "VerticalSwipeController";

	private static final float RECATCH_REJECTION_FRACTION = .0875f;
	private static final int SINGLE_FRAME_MS = 16;

	// Progress after which the transition is assumed to be a success in case user does not fling
	private static final float SUCCESS_TRANSITION_PROGRESS = 0.5f;

	protected final Launcher mLauncher;
	private final SwipeDetector mDetector;
	private final LauncherState mBaseState;

	private boolean mNoIntercept;

	private AnimatorPlaybackController mCurrentAnimation;
	private LauncherState mToState;

	private float mStartProgress;
	// Ratio of transition process [0, 1] to drag displacement (px)
	private float mProgressMultiplier;

	private SpringAnimationHandler[] mSpringHandlers;

	public VerticalSwipeController(Launcher l, LauncherState baseState) {
	mLauncher = l;
	mDetector = new SwipeDetector(l, this, SwipeDetector.VERTICAL);
	mBaseState = baseState;
	}

	private boolean canInterceptTouch(MotionEvent ev) {
	if (mCurrentAnimation != null) {
	// If we are already animating from a previous state, we can intercept.
	return true;
	}
	if (AbstractFloatingView.getTopOpenView(mLauncher) != null) {
	return false;
	}
	return shouldInterceptTouch(ev);
	}

	protected abstract boolean shouldInterceptTouch(MotionEvent ev);

	@Override
	public void onAnimationCancel(Animator animation) {
	if (mCurrentAnimation != null && animation == mCurrentAnimation.getTarget()) {
	Log.e(TAG, "Who dare cancel the animation when I am in control", new Exception());
	mDetector.finishedScrolling();
	mCurrentAnimation = null;
	}
	}

	private void initSprings() {
	AllAppsContainerView appsView = mLauncher.getAppsView();

	SpringAnimationHandler handler = appsView.getSpringAnimationHandler();
	if (handler == null) {
	mSpringHandlers = new SpringAnimationHandler[0];
	return;
	}

	ArrayList<SpringAnimationHandler> handlers = new ArrayList<>();
	handlers.add(handler);

	SpringAnimation searchSpring = appsView.getSearchUiManager().getSpringForFling();
	if (searchSpring != null) {
	SpringAnimationHandler searchHandler =
	new SpringAnimationHandler(Y_DIRECTION, handler.getFactory());
	searchHandler.add(searchSpring, true /* setDefaultValues */);
	handlers.add(searchHandler);
	}

	mSpringHandlers = handlers.toArray(new SpringAnimationHandler[handlers.size()]);
	}

	@Override
	public boolean onControllerInterceptTouchEvent(MotionEvent ev) {
	if (ev.getAction() == MotionEvent.ACTION_DOWN) {
	mNoIntercept = !canInterceptTouch(ev);
	if (mNoIntercept) {
	return false;
	}

	// Now figure out which direction scroll events the controller will start
	// calling the callbacks.
	final int directionsToDetectScroll;
	boolean ignoreSlopWhenSettling = false;

	if (mCurrentAnimation != null) {
	if (mCurrentAnimation.getProgressFraction() > 1 - RECATCH_REJECTION_FRACTION) {
	directionsToDetectScroll = SwipeDetector.DIRECTION_POSITIVE;
	} else if (mCurrentAnimation.getProgressFraction() < RECATCH_REJECTION_FRACTION ) {
	directionsToDetectScroll = SwipeDetector.DIRECTION_NEGATIVE;
	} else {
	directionsToDetectScroll = SwipeDetector.DIRECTION_BOTH;
	ignoreSlopWhenSettling = true;
	}
	} else {
	directionsToDetectScroll = getSwipeDirection(ev);
	}

	mDetector.setDetectableScrollConditions(
	directionsToDetectScroll, ignoreSlopWhenSettling);

	if (mSpringHandlers == null) {
	initSprings();
	}
	}

	if (mNoIntercept) {
	return false;
	}

	onControllerTouchEvent(ev);
	return mDetector.isDraggingOrSettling();
	}

	protected abstract int getSwipeDirection(MotionEvent ev);

	@Override
	public boolean onControllerTouchEvent(MotionEvent ev) {
	for (SpringAnimationHandler h : mSpringHandlers) {
	h.addMovement(ev);
	}
	return mDetector.onTouchEvent(ev);
	}

	@Override
	public void onDragStart(boolean start) {
	if (mCurrentAnimation == null) {
	float range = getShiftRange();
	long maxAccuracy = (long) (2 * range);

	// Build current animation
	mToState = mLauncher.isInState(ALL_APPS) ? mBaseState : ALL_APPS;
	mCurrentAnimation = mLauncher.getStateManager()
	.createAnimationToNewWorkspace(mToState, maxAccuracy);
	mCurrentAnimation.getTarget().addListener(this);
	mStartProgress = 0;
	mProgressMultiplier = (mLauncher.isInState(ALL_APPS) ? 1 : -1) / range;
	mCurrentAnimation.dispatchOnStart();
	} else {
	mCurrentAnimation.pause();
	mStartProgress = mCurrentAnimation.getProgressFraction();
	}

	for (SpringAnimationHandler h : mSpringHandlers) {
	h.skipToEnd();
	}
	}

	private float getShiftRange() {
	return mLauncher.getAllAppsController().getShiftRange();
	}

	@Override
	public boolean onDrag(float displacement, float velocity) {
	float deltaProgress = mProgressMultiplier * displacement;
	mCurrentAnimation.setPlayFraction(deltaProgress + mStartProgress);
	return true;
	}

	@Override
	public void onDragEnd(float velocity, boolean fling) {
	final long animationDuration;
	final LauncherState targetState;
	final float progress = mCurrentAnimation.getProgressFraction();

	if (fling) {
	if (velocity < 0) {
	targetState = ALL_APPS;
	animationDuration = SwipeDetector.calculateDuration(velocity,
	mToState == ALL_APPS ? (1 - progress) : progress);
	} else {
	targetState = mBaseState;
	animationDuration = SwipeDetector.calculateDuration(velocity,
	mToState == ALL_APPS ? progress : (1 - progress));
	}
	// snap to top or bottom using the release velocity
	} else {
	if (progress > SUCCESS_TRANSITION_PROGRESS) {
	targetState = mToState;
	animationDuration = SwipeDetector.calculateDuration(velocity, 1 - progress);
	} else {
	targetState = mToState == ALL_APPS ? mBaseState : ALL_APPS;
	animationDuration = SwipeDetector.calculateDuration(velocity, progress);
	}
	}

	if (fling && targetState == ALL_APPS) {
	for (SpringAnimationHandler h : mSpringHandlers) {
	// The icons are moving upwards, so we go to 0 from 1. (y-axis 1 is below 0.)
	h.animateToFinalPosition(0 /* pos /, 1 / startValue */);
	}
	}

	mCurrentAnimation.setEndAction(() -> {
	mLauncher.getStateManager().goToState(targetState, false);
	onTransitionComplete(fling, targetState == mToState);
	mDetector.finishedScrolling();
	mCurrentAnimation = null;
	});

	float nextFrameProgress = Utilities.boundToRange(
	progress + velocity * SINGLE_FRAME_MS / getShiftRange(), 0f, 1f);

	ValueAnimator anim = mCurrentAnimation.getAnimationPlayer();
	anim.setFloatValues(nextFrameProgress, targetState == mToState ? 1f : 0f);
	anim.setDuration(animationDuration);
	anim.setInterpolator(scrollInterpolatorForVelocity(velocity));
	anim.start();
	}

	protected abstract void onTransitionComplete(boolean wasFling, boolean stateChanged);
	}