Java tutorial
/* * Copyright (C) 2015 Two Toasters * * 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.twotoasters.jazzylistview; import android.content.Context; import android.content.res.TypedArray; import android.support.v4.view.ViewCompat; import android.support.v4.view.ViewPropertyAnimatorCompat; import android.util.AttributeSet; import android.view.View; import android.view.ViewGroup; import android.view.animation.AccelerateDecelerateInterpolator; import android.widget.AbsListView; import com.twotoasters.jazzylistview.effects.CardsEffect; import com.twotoasters.jazzylistview.effects.CurlEffect; import com.twotoasters.jazzylistview.effects.FadeEffect; import com.twotoasters.jazzylistview.effects.FanEffect; import com.twotoasters.jazzylistview.effects.FlipEffect; import com.twotoasters.jazzylistview.effects.FlyEffect; import com.twotoasters.jazzylistview.effects.GrowEffect; import com.twotoasters.jazzylistview.effects.HelixEffect; import com.twotoasters.jazzylistview.effects.ReverseFlyEffect; import com.twotoasters.jazzylistview.effects.SlideInEffect; import com.twotoasters.jazzylistview.effects.StandardEffect; import com.twotoasters.jazzylistview.effects.TiltEffect; import com.twotoasters.jazzylistview.effects.TwirlEffect; import com.twotoasters.jazzylistview.effects.WaveEffect; import com.twotoasters.jazzylistview.effects.ZipperEffect; import java.util.HashSet; public class JazzyHelper implements AbsListView.OnScrollListener { public static final int STANDARD = 0; public static final int GROW = 1; public static final int CARDS = 2; public static final int CURL = 3; public static final int WAVE = 4; public static final int FLIP = 5; public static final int FLY = 6; public static final int REVERSE_FLY = 7; public static final int HELIX = 8; public static final int FAN = 9; public static final int TILT = 10; public static final int ZIPPER = 11; public static final int FADE = 12; public static final int TWIRL = 13; public static final int SLIDE_IN = 14; public static final int DURATION = 300; public static final int OPAQUE = 1, TRANSPARENT = 0; private JazzyEffect mTransitionEffect = null; private boolean mIsScrolling = false; private int mFirstVisibleItem = -1; private int mLastVisibleItem = -1; private int mPreviousFirstVisibleItem = 0; private long mPreviousEventTime = 0; private double mSpeed = 0; private int mMaxVelocity = 0; public static final int MAX_VELOCITY_OFF = 0; private AbsListView.OnScrollListener mAdditionalOnScrollListener; private boolean mOnlyAnimateNewItems; private boolean mOnlyAnimateOnFling; private boolean mIsFlingEvent; private boolean mSimulateGridWithList; private final HashSet<Integer> mAlreadyAnimatedItems; public JazzyHelper() { this(null, null); } public JazzyHelper(Context context, AttributeSet attrs) { mAlreadyAnimatedItems = new HashSet<>(); int transitionEffect = HELIX; int maxVelocity = 0; if (context != null && attrs != null) { TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.JazzyListView); transitionEffect = a.getInteger(R.styleable.JazzyListView_effect, STANDARD); maxVelocity = a.getInteger(R.styleable.JazzyListView_max_velocity, MAX_VELOCITY_OFF); mOnlyAnimateNewItems = a.getBoolean(R.styleable.JazzyListView_only_animate_new_items, false); mOnlyAnimateOnFling = a.getBoolean(R.styleable.JazzyListView_only_animate_fling, false); mSimulateGridWithList = a.getBoolean(R.styleable.JazzyListView_simulate_grid_with_list, false); a.recycle(); } setTransitionEffect(transitionEffect); setMaxAnimationVelocity(maxVelocity); } public void setOnScrollListener(AbsListView.OnScrollListener l) { // hijack the scroll listener setter and have this list also notify the additional listener mAdditionalOnScrollListener = l; } /** * @see AbsListView.OnScrollListener#onScroll */ @Override public final void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { onScrolled(view, firstVisibleItem, visibleItemCount, totalItemCount); notifyAdditionalOnScrollListener(view, firstVisibleItem, visibleItemCount, totalItemCount); } public final void onScrolled(ViewGroup viewGroup, int firstVisibleItem, int visibleItemCount, int totalItemCount) { boolean shouldAnimateItems = (mFirstVisibleItem != -1 && mLastVisibleItem != -1); int lastVisibleItem = firstVisibleItem + visibleItemCount - 1; if (mIsScrolling && shouldAnimateItems) { setVelocity(firstVisibleItem, totalItemCount); int indexAfterFirst = 0; while (firstVisibleItem + indexAfterFirst < mFirstVisibleItem) { View item = viewGroup.getChildAt(indexAfterFirst); if (item != null) { doJazziness(item, firstVisibleItem + indexAfterFirst, -1); } indexAfterFirst++; } int indexBeforeLast = 0; while (lastVisibleItem - indexBeforeLast > mLastVisibleItem) { View item = viewGroup.getChildAt(lastVisibleItem - firstVisibleItem - indexBeforeLast); if (item != null) { doJazziness(item, lastVisibleItem - indexBeforeLast, 1); } indexBeforeLast++; } } else if (!shouldAnimateItems) { for (int i = firstVisibleItem; i < visibleItemCount; i++) { mAlreadyAnimatedItems.add(i); } } mFirstVisibleItem = firstVisibleItem; mLastVisibleItem = lastVisibleItem; } /** * Should be called in onScroll to keep take of current Velocity. * * @param firstVisibleItem The index of the first visible item in the ListView. */ private void setVelocity(int firstVisibleItem, int totalItemCount) { if (mMaxVelocity > MAX_VELOCITY_OFF && mPreviousFirstVisibleItem != firstVisibleItem) { long currTime = System.currentTimeMillis(); long timeToScrollOneItem = currTime - mPreviousEventTime; if (timeToScrollOneItem < 1) { double newSpeed = ((1.0d / timeToScrollOneItem) * 1000); // We need to normalize velocity so different size item don't // give largely different velocities. if (newSpeed < (0.9f * mSpeed)) { mSpeed *= 0.9f; } else if (newSpeed > (1.1f * mSpeed)) { mSpeed *= 1.1f; } else { mSpeed = newSpeed; } } else { mSpeed = ((1.0d / timeToScrollOneItem) * 1000); } mPreviousFirstVisibleItem = firstVisibleItem; mPreviousEventTime = currTime; } } /** * Initializes the item view and triggers the animation. * * @param item The view to be animated. * @param position The index of the view in the list. * @param scrollDirection Positive number indicating scrolling down, or negative number indicating scrolling up. */ private void doJazziness(View item, int position, int scrollDirection) { if (mIsScrolling) { if (mOnlyAnimateNewItems && mAlreadyAnimatedItems.contains(position)) return; if (mOnlyAnimateOnFling && !mIsFlingEvent) return; if (mMaxVelocity > MAX_VELOCITY_OFF && mMaxVelocity < mSpeed) return; if (mSimulateGridWithList) { ViewGroup itemRow = (ViewGroup) item; for (int i = 0; i < itemRow.getChildCount(); i++) doJazzinessImpl(itemRow.getChildAt(i), position, scrollDirection); } else { doJazzinessImpl(item, position, scrollDirection); } mAlreadyAnimatedItems.add(position); } } private void doJazzinessImpl(View item, int position, int scrollDirection) { ViewPropertyAnimatorCompat animator = ViewCompat.animate(item).setDuration(DURATION) .setInterpolator(new AccelerateDecelerateInterpolator()); scrollDirection = scrollDirection > 0 ? 1 : -1; mTransitionEffect.initView(item, position, scrollDirection); mTransitionEffect.setupAnimation(item, position, scrollDirection, animator); animator.start(); } /** * @see AbsListView.OnScrollListener#onScrollStateChanged */ @Override public void onScrollStateChanged(AbsListView view, int scrollState) { switch (scrollState) { case AbsListView.OnScrollListener.SCROLL_STATE_IDLE: mIsScrolling = false; mIsFlingEvent = false; break; case AbsListView.OnScrollListener.SCROLL_STATE_FLING: mIsFlingEvent = true; break; case AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL: mIsScrolling = true; mIsFlingEvent = false; break; default: break; } notifyAdditionalOnScrollStateChangedListener(view, scrollState); } public void setTransitionEffect(int transitionEffect) { switch (transitionEffect) { case STANDARD: setTransitionEffect(new StandardEffect()); break; case GROW: setTransitionEffect(new GrowEffect()); break; case CARDS: setTransitionEffect(new CardsEffect()); break; case CURL: setTransitionEffect(new CurlEffect()); break; case WAVE: setTransitionEffect(new WaveEffect()); break; case FLIP: setTransitionEffect(new FlipEffect()); break; case FLY: setTransitionEffect(new FlyEffect()); break; case REVERSE_FLY: setTransitionEffect(new ReverseFlyEffect()); break; case HELIX: setTransitionEffect(new HelixEffect()); break; case FAN: setTransitionEffect(new FanEffect()); break; case TILT: setTransitionEffect(new TiltEffect()); break; case ZIPPER: setTransitionEffect(new ZipperEffect()); break; case FADE: setTransitionEffect(new FadeEffect()); break; case TWIRL: setTransitionEffect(new TwirlEffect()); break; case SLIDE_IN: setTransitionEffect(new SlideInEffect()); break; default: break; } } public void setTransitionEffect(JazzyEffect transitionEffect) { mTransitionEffect = transitionEffect; } public void setShouldOnlyAnimateNewItems(boolean onlyAnimateNew) { mOnlyAnimateNewItems = onlyAnimateNew; } public void setShouldOnlyAnimateFling(boolean onlyFling) { mOnlyAnimateOnFling = onlyFling; } public void setMaxAnimationVelocity(int itemsPerSecond) { mMaxVelocity = itemsPerSecond; } public void setSimulateGridWithList(boolean simulateGridWithList) { mSimulateGridWithList = simulateGridWithList; } public void setScrolling(boolean isScrolling) { mIsScrolling = isScrolling; } public void setFlingEvent(boolean isFlingEvent) { mIsFlingEvent = isFlingEvent; } /** * Notifies the OnScrollListener of an onScroll event, since JazzyListView is the primary listener for onScroll events. */ private void notifyAdditionalOnScrollListener(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { if (mAdditionalOnScrollListener != null) { mAdditionalOnScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount); } } /** * Notifies the OnScrollListener of an onScrollStateChanged event, since JazzyListView is the primary listener for onScrollStateChanged events. */ private void notifyAdditionalOnScrollStateChangedListener(AbsListView view, int scrollState) { if (mAdditionalOnScrollListener != null) { mAdditionalOnScrollListener.onScrollStateChanged(view, scrollState); } } }