/* * Copyright (C) 2012 Google Inc. * Licensed to 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.mail.ui; import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.animation.ObjectAnimator; import android.animation.ValueAnimator; import android.animation.ValueAnimator.AnimatorUpdateListener; import android.content.Context; import android.content.res.Resources; import android.graphics.RectF; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.animation.DecelerateInterpolator; import com.android.mail.R; import com.android.mail.utils.LogUtils; import com.android.mail.utils.Utils; public class SwipeHelper { static final String TAG = "com.android.systemui.SwipeHelper"; private static final boolean DEBUG_INVALIDATE = false; private static final boolean CONSTRAIN_SWIPE = true; private static final boolean FADE_OUT_DURING_SWIPE = true; private static final boolean DISMISS_IF_SWIPED_FAR_ENOUGH = true; // Turn on for debugging only during development. private static final boolean LOG_SWIPE_DISMISS_VELOCITY = false; public static final int X = 0; public static final int Y = 1; private static DecelerateInterpolator sDecelerateInterpolator = new DecelerateInterpolator(1.0f); private static int SWIPE_ESCAPE_VELOCITY = -1; private static int DEFAULT_ESCAPE_ANIMATION_DURATION; private static int MAX_ESCAPE_ANIMATION_DURATION; private static int MAX_DISMISS_VELOCITY; private static int SNAP_ANIM_LEN; private static float MIN_SWIPE; public static float ALPHA_FADE_START = 0f; // fraction of thumbnail width // where fade starts public static float ALPHA_TEXT_FADE_START = 0.4f; static final float ALPHA_FADE_END = 0.7f; // fraction of thumbnail width // beyond which alpha->0 private static final float FACTOR = 1.2f; /* Dead region where swipe cannot be initiated. */ private final static int DEAD_REGION_FOR_SWIPE = 56; private float mPagingTouchSlop; private final Callback mCallback; private final int mSwipeDirection; private final VelocityTracker mVelocityTracker; private float mInitialTouchPosX; private boolean mDragging; private SwipeableItemView mCurrView; private View mCurrAnimView; private boolean mCanCurrViewBeDimissed; private float mDensityScale; private float mLastY; private float mInitialTouchPosY; private LeaveBehindItem mPrevView; public SwipeHelper(Context context, int swipeDirection, Callback callback, float densityScale, float pagingTouchSlop) { mCallback = callback; mSwipeDirection = swipeDirection; mVelocityTracker = VelocityTracker.obtain(); mDensityScale = densityScale; mPagingTouchSlop = pagingTouchSlop; if (SWIPE_ESCAPE_VELOCITY == -1) { Resources res = context.getResources(); SWIPE_ESCAPE_VELOCITY = res.getInteger(R.integer.swipe_escape_velocity); DEFAULT_ESCAPE_ANIMATION_DURATION = res.getInteger(R.integer.escape_animation_duration); MAX_ESCAPE_ANIMATION_DURATION = res.getInteger(R.integer.max_escape_animation_duration); MAX_DISMISS_VELOCITY = res.getInteger(R.integer.max_dismiss_velocity); SNAP_ANIM_LEN = res.getInteger(R.integer.snap_animation_duration); MIN_SWIPE = res.getDimension(R.dimen.min_swipe); } } public void setDensityScale(float densityScale) { mDensityScale = densityScale; } public void setPagingTouchSlop(float pagingTouchSlop) { mPagingTouchSlop = pagingTouchSlop; } private float getVelocity(VelocityTracker vt) { return mSwipeDirection == X ? vt.getXVelocity() : vt.getYVelocity(); } private ObjectAnimator createTranslationAnimation(View v, float newPos) { ObjectAnimator anim = ObjectAnimator.ofFloat(v, mSwipeDirection == X ? "translationX" : "translationY", newPos); return anim; } private ObjectAnimator createDismissAnimation(View v, float newPos, int duration) { ObjectAnimator anim = createTranslationAnimation(v, newPos); anim.setInterpolator(sDecelerateInterpolator); anim.setDuration(duration); return anim; } private float getPerpendicularVelocity(VelocityTracker vt) { return mSwipeDirection == X ? vt.getYVelocity() : vt.getXVelocity(); } private void setTranslation(View v, float translate) { if (mSwipeDirection == X) { v.setTranslationX(translate); } else { v.setTranslationY(translate); } } private float getSize(View v) { return mSwipeDirection == X ? v.getMeasuredWidth() : v.getMeasuredHeight(); } private float getAlphaForOffset(View view) { float viewSize = getSize(view); final float fadeSize = ALPHA_FADE_END * viewSize; float result = 1.0f; float pos = view.getTranslationX(); if (pos >= viewSize * ALPHA_FADE_START) { result = 1.0f - (pos - viewSize * ALPHA_FADE_START) / fadeSize; } else if (pos < viewSize * (1.0f - ALPHA_FADE_START)) { result = 1.0f + (viewSize * ALPHA_FADE_START + pos) / fadeSize; } float minAlpha = 0.5f; return Math.max(minAlpha, result); } private float getTextAlphaForOffset(View view) { float viewSize = getSize(view); final float fadeSize = ALPHA_TEXT_FADE_START * viewSize; float result = 1.0f; float pos = view.getTranslationX(); if (pos >= 0) { result = 1.0f - pos / fadeSize; } else if (pos < 0) { result = 1.0f + pos / fadeSize; } return Math.max(0, result); } // invalidate the view's own bounds all the way up the view hierarchy public static void invalidateGlobalRegion(View view) { invalidateGlobalRegion( view, new RectF(view.getLeft(), view.getTop(), view.getRight(), view.getBottom())); } // invalidate a rectangle relative to the view's coordinate system all the way up the view // hierarchy public static void invalidateGlobalRegion(View view, RectF childBounds) { //childBounds.offset(view.getTranslationX(), view.getTranslationY()); if (DEBUG_INVALIDATE) LogUtils.v(TAG, "-------------"); while (view.getParent() != null && view.getParent() instanceof View) { view = (View) view.getParent(); view.getMatrix().mapRect(childBounds); view.invalidate((int) Math.floor(childBounds.left), (int) Math.floor(childBounds.top), (int) Math.ceil(childBounds.right), (int) Math.ceil(childBounds.bottom)); if (DEBUG_INVALIDATE) { LogUtils.v(TAG, "INVALIDATE(" + (int) Math.floor(childBounds.left) + "," + (int) Math.floor(childBounds.top) + "," + (int) Math.ceil(childBounds.right) + "," + (int) Math.ceil(childBounds.bottom)); } } } public boolean onInterceptTouchEvent(MotionEvent ev) { final int action = ev.getAction(); switch (action) { case MotionEvent.ACTION_DOWN: mLastY = ev.getY(); mDragging = false; View view = mCallback.getChildAtPosition(ev); if (view instanceof SwipeableItemView) { mCurrView = (SwipeableItemView) view; } mVelocityTracker.clear(); if (mCurrView != null) { mCurrAnimView = mCurrView.getSwipeableView().getView(); mCanCurrViewBeDimissed = mCallback.canChildBeDismissed(mCurrView); mVelocityTracker.addMovement(ev); mInitialTouchPosX = ev.getX(); mInitialTouchPosY = ev.getY(); } mCallback.cancelDismissCounter(); break; case MotionEvent.ACTION_MOVE: if (mCurrView != null) { // Check the movement direction. if (mLastY >= 0 && !mDragging) { float currY = ev.getY(); float currX = ev.getX(); float deltaY = Math.abs(currY - mInitialTouchPosY); float deltaX = Math.abs(currX - mInitialTouchPosX); if (deltaY > mCurrView.getMinAllowScrollDistance() && deltaY > (FACTOR * deltaX)) { mLastY = ev.getY(); mCallback.onScroll(); return false; } } mVelocityTracker.addMovement(ev); float pos = ev.getX(); float delta = pos - mInitialTouchPosX; if (Math.abs(delta) > mPagingTouchSlop) { mCallback.onBeginDrag(mCurrView.getSwipeableView().getView()); mPrevView = mCallback.getLastSwipedItem(); mDragging = true; mInitialTouchPosX = ev.getX() - mCurrAnimView.getTranslationX(); mInitialTouchPosY = ev.getY(); } } mLastY = ev.getY(); break; case MotionEvent.ACTION_UP: case MotionEvent.ACTION_CANCEL: mDragging = false; mCurrView = null; mCurrAnimView = null; mLastY = -1; break; } return mDragging; } /** * @param view The view to be dismissed * @param velocity The desired pixels/second speed at which the view should * move */ private void dismissChild(final SwipeableItemView view, float velocity) { final View animView = view.getSwipeableView().getView(); final boolean canAnimViewBeDismissed = mCallback.canChildBeDismissed(view); float newPos = determinePos(animView, velocity); int duration = determineDuration(animView, newPos, velocity); Utils.enableHardwareLayer(animView); ObjectAnimator anim = createDismissAnimation(animView, newPos, duration); anim.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { mCallback.onChildDismissed(view); animView.setLayerType(View.LAYER_TYPE_NONE, null); } }); anim.addUpdateListener(new AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { if (FADE_OUT_DURING_SWIPE && canAnimViewBeDismissed) { animView.setAlpha(getAlphaForOffset(animView)); } invalidateGlobalRegion(animView); } }); anim.start(); } private static int determineDuration(View animView, float newPos, float velocity) { int duration = MAX_ESCAPE_ANIMATION_DURATION; if (velocity != 0) { duration = Math .min(duration, (int) (Math.abs(newPos - animView.getTranslationX()) * 1000f / Math .abs(velocity))); } else { duration = DEFAULT_ESCAPE_ANIMATION_DURATION; } return duration; } private float determinePos(View animView, float velocity) { final float newPos; if (velocity < 0 || (velocity == 0 && animView.getTranslationX() < 0) // if we use the Menu to dismiss an item in landscape, animate up || (velocity == 0 && animView.getTranslationX() == 0 && mSwipeDirection == Y)) { newPos = -getSize(animView); } else { newPos = getSize(animView); } return newPos; } public void snapChild(final SwipeableItemView view) { final View animView = view.getSwipeableView().getView(); final boolean canAnimViewBeDismissed = mCallback.canChildBeDismissed(view); final ObjectAnimator anim = createTranslationAnimation(animView, 0); final int duration = SNAP_ANIM_LEN; anim.setDuration(duration); anim.addUpdateListener(new AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { if (FADE_OUT_DURING_SWIPE && canAnimViewBeDismissed) { animView.setAlpha(getAlphaForOffset(animView)); } invalidateGlobalRegion(animView); } }); anim.addListener(new Animator.AnimatorListener() { @Override public void onAnimationStart(Animator animation) { } @Override public void onAnimationEnd(Animator animation) { animView.setAlpha(1.0f); mCallback.onDragCancelled(mCurrView); } @Override public void onAnimationCancel(Animator animation) { } @Override public void onAnimationRepeat(Animator animation) { } }); anim.start(); } public boolean onTouchEvent(MotionEvent ev) { if (!mDragging) { return false; } mVelocityTracker.addMovement(ev); final int action = ev.getAction(); switch (action) { case MotionEvent.ACTION_OUTSIDE: case MotionEvent.ACTION_MOVE: if (mCurrView != null) { float deltaX = ev.getX() - mInitialTouchPosX; // If the swipe started in the dead region, ignore it. if (mInitialTouchPosX <= (DEAD_REGION_FOR_SWIPE * mDensityScale)){ return true; } // If the user has gone vertical and not gone horizontalish AT // LEAST minBeforeLock, switch to scroll. Otherwise, cancel // the swipe. float minDistance = MIN_SWIPE; if (Math.abs(deltaX) < minDistance) { // Don't start the drag until at least X distance has // occurred. return true; } // don't let items that can't be dismissed be dragged more // than maxScrollDistance if (CONSTRAIN_SWIPE && !mCallback.canChildBeDismissed(mCurrView)) { float size = getSize(mCurrAnimView); float maxScrollDistance = 0.15f * size; if (Math.abs(deltaX) >= size) { deltaX = deltaX > 0 ? maxScrollDistance : -maxScrollDistance; } else { deltaX = maxScrollDistance * (float) Math.sin((deltaX / size) * (Math.PI / 2)); } } setTranslation(mCurrAnimView, deltaX); if (FADE_OUT_DURING_SWIPE && mCanCurrViewBeDimissed) { mCurrAnimView.setAlpha(getAlphaForOffset(mCurrAnimView)); if (mPrevView != null) { // Base how much the text of the prev item is faded // on how far the current item has moved. mPrevView.setTextAlpha(getTextAlphaForOffset(mCurrAnimView)); } } invalidateGlobalRegion(mCurrView.getSwipeableView().getView()); } break; case MotionEvent.ACTION_UP: case MotionEvent.ACTION_CANCEL: if (mCurrView != null) { float maxVelocity = MAX_DISMISS_VELOCITY * mDensityScale; mVelocityTracker.computeCurrentVelocity(1000 /* px/sec */, maxVelocity); float escapeVelocity = SWIPE_ESCAPE_VELOCITY * mDensityScale; float velocity = getVelocity(mVelocityTracker); float perpendicularVelocity = getPerpendicularVelocity(mVelocityTracker); // Decide whether to dismiss the current view // Tweak constants below as required to prevent erroneous // swipe/dismiss float translation = Math.abs(mCurrAnimView.getTranslationX()); float currAnimViewSize = getSize(mCurrAnimView); // Long swipe = translation of .4 * width boolean childSwipedFarEnough = DISMISS_IF_SWIPED_FAR_ENOUGH && translation > 0.4 * currAnimViewSize; // Fast swipe = > escapeVelocity and translation of .1 * // width boolean childSwipedFastEnough = (Math.abs(velocity) > escapeVelocity) && (Math.abs(velocity) > Math.abs(perpendicularVelocity)) && (velocity > 0) == (mCurrAnimView.getTranslationX() > 0) && translation > 0.05 * currAnimViewSize; if (LOG_SWIPE_DISMISS_VELOCITY) { LogUtils.v(TAG, "Swipe/Dismiss: " + velocity + "/" + escapeVelocity + "/" + perpendicularVelocity + ", x: " + translation + "/" + currAnimViewSize); } boolean dismissChild = mCallback.canChildBeDismissed(mCurrView) && (childSwipedFastEnough || childSwipedFarEnough); if (dismissChild) { dismissChild(mCurrView, childSwipedFastEnough ? velocity : 0f); } else { snapChild(mCurrView); } } break; } return true; } public interface Callback { View getChildAtPosition(MotionEvent ev); void cancelDismissCounter(); void onScroll(); boolean canChildBeDismissed(SwipeableItemView v); void onBeginDrag(View v); void onChildDismissed(SwipeableItemView v); void onDragCancelled(SwipeableItemView v); ConversationCheckedSet getCheckedSet(); LeaveBehindItem getLastSwipedItem(); } }