Java tutorial
/** * * Apache License * Version 2.0, January 2004 * http://www.apache.org/licenses/ * * TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION * * 1. Definitions. * * "License" shall mean the terms and conditions for use, reproduction, * and distribution as defined by Sections 1 through 9 of this document. * * "Licensor" shall mean the copyright owner or entity authorized by * the copyright owner that is granting the License. * * "Legal Entity" shall mean the union of the acting entity and all * other entities that control, are controlled by, or are under common * control with that entity. For the purposes of this definition, * "control" means (i) the power, direct or indirect, to cause the * direction or management of such entity, whether by contract or * otherwise, or (ii) ownership of fifty percent (50%) or more of the * outstanding shares, or (iii) beneficial ownership of such entity. * * "You" (or "Your") shall mean an individual or Legal Entity * exercising permissions granted by this License. * * "Source" form shall mean the preferred form for making modifications, * including but not limited to software source code, documentation * source, and configuration files. * * "Object" form shall mean any form resulting from mechanical * transformation or translation of a Source form, including but * not limited to compiled object code, generated documentation, * and conversions to other media types. * * "Work" shall mean the work of authorship, whether in Source or * Object form, made available under the License, as indicated by a * copyright notice that is included in or attached to the work * (an example is provided in the Appendix below). * * "Derivative Works" shall mean any work, whether in Source or Object * form, that is based on (or derived from) the Work and for which the * editorial revisions, annotations, elaborations, or other modifications * represent, as a whole, an original work of authorship. For the purposes * of this License, Derivative Works shall not include works that remain * separable from, or merely link (or bind by name) to the interfaces of, * the Work and Derivative Works thereof. * * "Contribution" shall mean any work of authorship, including * the original version of the Work and any modifications or additions * to that Work or Derivative Works thereof, that is intentionally * submitted to Licensor for inclusion in the Work by the copyright owner * or by an individual or Legal Entity authorized to submit on behalf of * the copyright owner. For the purposes of this definition, "submitted" * means any form of electronic, verbal, or written communication sent * to the Licensor or its representatives, including but not limited to * communication on electronic mailing lists, source code control systems, * and issue tracking systems that are managed by, or on behalf of, the * Licensor for the purpose of discussing and improving the Work, but * excluding communication that is conspicuously marked or otherwise * designated in writing by the copyright owner as "Not a Contribution." * * "Contributor" shall mean Licensor and any individual or Legal Entity * on behalf of whom a Contribution has been received by Licensor and * subsequently incorporated within the Work. * * 2. Grant of Copyright License. Subject to the terms and conditions of * this License, each Contributor hereby grants to You a perpetual, * worldwide, non-exclusive, no-charge, royalty-free, irrevocable * copyright license to reproduce, prepare Derivative Works of, * publicly display, publicly perform, sublicense, and distribute the * Work and such Derivative Works in Source or Object form. * * 3. Grant of Patent License. Subject to the terms and conditions of * this License, each Contributor hereby grants to You a perpetual, * worldwide, non-exclusive, no-charge, royalty-free, irrevocable * (except as stated in this section) patent license to make, have made, * use, offer to sell, sell, import, and otherwise transfer the Work, * where such license applies only to those patent claims licensable * by such Contributor that are necessarily infringed by their * Contribution(s) alone or by combination of their Contribution(s) * with the Work to which such Contribution(s) was submitted. If You * institute patent litigation against any entity (including a * cross-claim or counterclaim in a lawsuit) alleging that the Work * or a Contribution incorporated within the Work constitutes direct * or contributory patent infringement, then any patent licenses * granted to You under this License for that Work shall terminate * as of the date such litigation is filed. * * 4. Redistribution. You may reproduce and distribute copies of the * Work or Derivative Works thereof in any medium, with or without * modifications, and in Source or Object form, provided that You * meet the following conditions: * * (a) You must give any other recipients of the Work or * Derivative Works a copy of this License; and * * (b) You must cause any modified files to carry prominent notices * stating that You changed the files; and * * (c) You must retain, in the Source form of any Derivative Works * that You distribute, all copyright, patent, trademark, and * attribution notices from the Source form of the Work, * excluding those notices that do not pertain to any part of * the Derivative Works; and * * (d) If the Work includes a "NOTICE" text file as part of its * distribution, then any Derivative Works that You distribute must * include a readable copy of the attribution notices contained * within such NOTICE file, excluding those notices that do not * pertain to any part of the Derivative Works, in at least one * of the following places: within a NOTICE text file distributed * as part of the Derivative Works; within the Source form or * documentation, if provided along with the Derivative Works; or, * within a display generated by the Derivative Works, if and * wherever such third-party notices normally appear. The contents * of the NOTICE file are for informational purposes only and * do not modify the License. You may add Your own attribution * notices within Derivative Works that You distribute, alongside * or as an addendum to the NOTICE text from the Work, provided * that such additional attribution notices cannot be construed * as modifying the License. * * You may add Your own copyright statement to Your modifications and * may provide additional or different license terms and conditions * for use, reproduction, or distribution of Your modifications, or * for any such Derivative Works as a whole, provided Your use, * reproduction, and distribution of the Work otherwise complies with * the conditions stated in this License. * * 5. Submission of Contributions. Unless You explicitly state otherwise, * any Contribution intentionally submitted for inclusion in the Work * by You to the Licensor shall be under the terms and conditions of * this License, without any additional terms or conditions. * Notwithstanding the above, nothing herein shall supersede or modify * the terms of any separate license agreement you may have executed * with Licensor regarding such Contributions. * * 6. Trademarks. This License does not grant permission to use the trade * names, trademarks, service marks, or product names of the Licensor, * except as required for reasonable and customary use in describing the * origin of the Work and reproducing the content of the NOTICE file. * * 7. Disclaimer of Warranty. Unless required by applicable law or * agreed to in writing, Licensor provides the Work (and each * Contributor provides its Contributions) on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or * implied, including, without limitation, any warranties or conditions * of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A * PARTICULAR PURPOSE. You are solely responsible for determining the * appropriateness of using or redistributing the Work and assume any * risks associated with Your exercise of permissions under this License. * * 8. Limitation of Liability. In no event and under no legal theory, * whether in tort (including negligence), contract, or otherwise, * unless required by applicable law (such as deliberate and grossly * negligent acts) or agreed to in writing, shall any Contributor be * liable to You for damages, including any direct, indirect, special, * incidental, or consequential damages of any character arising as a * result of this License or out of the use or inability to use the * Work (including but not limited to damages for loss of goodwill, * work stoppage, computer failure or malfunction, or any and all * other commercial damages or losses), even if such Contributor * has been advised of the possibility of such damages. * * 9. Accepting Warranty or Additional Liability. While redistributing * the Work or Derivative Works thereof, You may choose to offer, * and charge a fee for, acceptance of support, warranty, indemnity, * or other liability obligations and/or rights consistent with this * License. However, in accepting such obligations, You may act only * on Your own behalf and on Your sole responsibility, not on behalf * of any other Contributor, and only if You agree to indemnify, * defend, and hold each Contributor harmless for any liability * incurred by, or claims asserted against, such Contributor by reason * of your accepting any such warranty or additional liability. * * END OF TERMS AND CONDITIONS * * APPENDIX: How to apply the Apache License to your work. * * To apply the Apache License to your work, attach the following * boilerplate notice, with the fields enclosed by brackets "[]" * replaced with your own identifying information. (Don't include * the brackets!) The text should be enclosed in the appropriate * comment syntax for the file format. We also recommend that a * file or class name and description of purpose be included on the * same "printed page" as the copyright notice for easier * identification within third-party archives. * * Copyright 2016 Alibaba Group * * 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.taobao.weex.ui.view; import android.annotation.SuppressLint; import android.content.Context; import android.graphics.Canvas; import android.graphics.Rect; import android.os.Handler; import android.os.Handler.Callback; import android.os.Message; import android.support.v4.view.NestedScrollingChild; import android.support.v4.view.NestedScrollingChildHelper; import android.support.v4.view.ViewCompat; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.widget.ScrollView; import com.taobao.weex.common.WXThread; import com.taobao.weex.ui.component.WXComponent; import com.taobao.weex.ui.component.WXScroller; import com.taobao.weex.ui.view.gesture.WXGesture; import com.taobao.weex.ui.view.gesture.WXGestureObservable; import com.taobao.weex.utils.WXLogUtils; import com.taobao.weex.utils.WXReflectionUtils; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Map.Entry; /** * Custom-defined scrollView */ public class WXScrollView extends ScrollView implements Callback, IWXScroller, WXGestureObservable, NestedScrollingChild { private NestedScrollingChildHelper childHelper; private float ox; private float oy; private int[] consumed = new int[2]; private int[] offsetInWindow = new int[2]; int mScrollX; int mScrollY; private WXGesture wxGesture; private List<WXScrollViewListener> mScrollViewListeners; private WXScroller mWAScroller; //sticky private View mCurrentStickyView; private boolean mRedirectTouchToStickyView; private int mStickyOffset; private boolean mHasNotDoneActionDown = true; @SuppressLint("HandlerLeak") private Handler mScrollerTask; private int mInitialPosition; private int mCheckTime = 100; /** * The location of mCurrentStickyView */ private int[] mStickyP = new int[2]; /** * Location of the scrollView */ private Rect mScrollRect; private int[] stickyScrollerP = new int[2]; private int[] stickyViewP = new int[2]; private boolean scrollable = true; public WXScrollView(Context context) { super(context); mScrollViewListeners = new ArrayList<>(); init(); try { WXReflectionUtils.setValue(this, "mMinimumVelocity", 5); } catch (Exception e) { WXLogUtils.e("[WXScrollView] WXScrollView: ", e); } } private void init() { setWillNotDraw(false); startScrollerTask(); setOverScrollMode(View.OVER_SCROLL_NEVER); childHelper = new NestedScrollingChildHelper(this); childHelper.setNestedScrollingEnabled(true); } public void startScrollerTask() { if (mScrollerTask == null) { mScrollerTask = new Handler(WXThread.secure(this)); } mInitialPosition = getScrollY(); mScrollerTask.sendEmptyMessageDelayed(0, mCheckTime); } public WXScrollView(Context context, AttributeSet attrs) { super(context, attrs); init(); } public WXScrollView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); setOverScrollMode(View.OVER_SCROLL_NEVER); } /** * Add listener for scrollView. */ public void addScrollViewListener(WXScrollViewListener scrollViewListener) { if (!mScrollViewListeners.contains(scrollViewListener)) { mScrollViewListeners.add(scrollViewListener); } } public void removeScrollViewListener(WXScrollViewListener scrollViewListener) { mScrollViewListeners.remove(scrollViewListener); } @Override public boolean dispatchTouchEvent(MotionEvent ev) { if (ev.getAction() == MotionEvent.ACTION_DOWN) { mRedirectTouchToStickyView = true; } if (mRedirectTouchToStickyView) { mRedirectTouchToStickyView = mCurrentStickyView != null; if (mRedirectTouchToStickyView) { mRedirectTouchToStickyView = ev.getY() <= mCurrentStickyView.getHeight() && ev.getX() >= mCurrentStickyView.getLeft() && ev.getX() <= mCurrentStickyView.getRight(); } } if (mRedirectTouchToStickyView) { if (mScrollRect == null) { mScrollRect = new Rect(); getGlobalVisibleRect(mScrollRect); } mCurrentStickyView.getLocationOnScreen(stickyViewP); ev.offsetLocation(0, stickyViewP[1] - mScrollRect.top); } return super.dispatchTouchEvent(ev); } @Override protected void dispatchDraw(Canvas canvas) { super.dispatchDraw(canvas); if (mCurrentStickyView != null) { canvas.save(); mCurrentStickyView.getLocationOnScreen(mStickyP); int realOffset = (mStickyOffset <= 0 ? mStickyOffset : 0); canvas.translate(mStickyP[0], getScrollY() + realOffset); canvas.clipRect(0, realOffset, mCurrentStickyView.getWidth(), mCurrentStickyView.getHeight()); mCurrentStickyView.draw(canvas); canvas.restore(); } } @Override public boolean onTouchEvent(MotionEvent ev) { if (!scrollable) { return true; // when scrollable is set to false, then eat the touch event } if (mRedirectTouchToStickyView) { if (mScrollRect == null) { mScrollRect = new Rect(); getGlobalVisibleRect(mScrollRect); } mCurrentStickyView.getLocationOnScreen(stickyViewP); ev.offsetLocation(0, -(stickyViewP[1] - mScrollRect.top)); } if (ev.getAction() == MotionEvent.ACTION_DOWN) { mHasNotDoneActionDown = false; } if (mHasNotDoneActionDown) { MotionEvent down = MotionEvent.obtain(ev); down.setAction(MotionEvent.ACTION_DOWN); mHasNotDoneActionDown = false; down.recycle(); } if (ev.getAction() == MotionEvent.ACTION_DOWN) { ox = ev.getX(); oy = ev.getY(); // Dispatch touch event to parent view startNestedScroll(ViewCompat.SCROLL_AXIS_HORIZONTAL | ViewCompat.SCROLL_AXIS_VERTICAL); } if (ev.getAction() == MotionEvent.ACTION_UP || ev.getAction() == MotionEvent.ACTION_CANCEL) { mHasNotDoneActionDown = true; // stop nested scrolling dispatch stopNestedScroll(); } if (ev.getAction() == MotionEvent.ACTION_MOVE) { float clampedX = ev.getX(); float clampedY = ev.getY(); int dx = (int) (ox - clampedX); int dy = (int) (oy - clampedY); if (dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow)) { // sub dx/dy was consumed by parent view!!! ev.setLocation(clampedX + consumed[0], clampedY + consumed[1]); } ox = ev.getX(); oy = ev.getY(); } boolean result = super.onTouchEvent(ev); if (wxGesture != null) { result |= wxGesture.onTouch(this, ev); } return result; } @Override public void setNestedScrollingEnabled(boolean enabled) { childHelper.setNestedScrollingEnabled(enabled); } @Override public boolean isNestedScrollingEnabled() { return childHelper.isNestedScrollingEnabled(); } @Override public boolean startNestedScroll(int axes) { return childHelper.startNestedScroll(axes); } @Override public void stopNestedScroll() { childHelper.stopNestedScroll(); } @Override public boolean hasNestedScrollingParent() { return childHelper.hasNestedScrollingParent(); } public boolean isScrollable() { return scrollable; } public void setScrollable(boolean scrollable) { this.scrollable = scrollable; } @Override public boolean dispatchNestedScroll(int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int[] offsetInWindow) { return childHelper.dispatchNestedScroll(dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, offsetInWindow); } @Override public boolean dispatchNestedPreScroll(int dx, int dy, int[] consumed, int[] offsetInWindow) { return childHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow); } @Override public boolean dispatchNestedFling(float velocityX, float velocityY, boolean consumed) { return childHelper.dispatchNestedFling(velocityX, velocityY, consumed); } @Override public boolean dispatchNestedPreFling(float velocityX, float velocityY) { return childHelper.dispatchNestedPreFling(velocityX, velocityY); } @Override public boolean onNestedPreFling(View target, float velocityX, float velocityY) { return dispatchNestedPreFling(velocityX, velocityY); } @Override public boolean onNestedFling(View target, float velocityX, float velocityY, boolean consumed) { return dispatchNestedFling(velocityX, velocityY, consumed); } @Override public void fling(int velocityY) { super.fling(velocityY); if (mScrollerTask != null) { mScrollerTask.removeMessages(0); } startScrollerTask(); } @Override protected void onScrollChanged(int x, int y, int oldx, int oldy) { mScrollX = getScrollX(); mScrollY = getScrollY(); onScroll(WXScrollView.this, mScrollX, mScrollY); View view = getChildAt(getChildCount() - 1); if (view == null) { return; } int d = view.getBottom(); d -= (getHeight() + mScrollY); if (d == 0) { onScrollToBottom(mScrollX, mScrollY); } int count = mScrollViewListeners == null ? 0 : mScrollViewListeners.size(); for (int i = 0; i < count; ++i) { mScrollViewListeners.get(i).onScrollChanged(this, x, y, oldx, oldy); } showStickyView(); } protected void onScroll(WXScrollView scrollView, int x, int y) { int count = mScrollViewListeners == null ? 0 : mScrollViewListeners.size(); for (int i = 0; i < count; ++i) { mScrollViewListeners.get(i).onScroll(this, x, y); } } protected void onScrollToBottom(int x, int y) { int count = mScrollViewListeners == null ? 0 : mScrollViewListeners.size(); for (int i = 0; i < count; ++i) { mScrollViewListeners.get(i).onScrollToBottom(this, x, y); } } private void showStickyView() { if (mWAScroller == null) { return; } View curStickyView = procSticky(mWAScroller.getStickMap()); if (curStickyView != null) { mCurrentStickyView = curStickyView; } else { mCurrentStickyView = null; } } private View procSticky(Map<String, HashMap<String, WXComponent>> mStickyMap) { if (mStickyMap == null) { return null; } HashMap<String, WXComponent> stickyMap = mStickyMap.get(mWAScroller.getRef()); if (stickyMap == null) { return null; } Iterator<Entry<String, WXComponent>> iterator = stickyMap.entrySet().iterator(); Entry<String, WXComponent> entry = null; WXComponent stickyData; while (iterator.hasNext()) { entry = iterator.next(); stickyData = entry.getValue(); getLocationOnScreen(stickyScrollerP); stickyData.getHostView().getLocationOnScreen(stickyViewP); int parentH = 0; if (stickyData.getParent() != null && stickyData.getParent().getRealView() != null) { parentH = stickyData.getParent().getRealView().getHeight(); } int stickyViewH = stickyData.getHostView().getHeight(); int stickyShowPos = stickyScrollerP[1]; int stickyStartHidePos = -parentH + stickyScrollerP[1] + stickyViewH; if (stickyViewP[1] <= stickyShowPos && stickyViewP[1] >= (stickyStartHidePos - stickyViewH)) { mStickyOffset = stickyViewP[1] - stickyStartHidePos; stickyData.setStickyOffset(stickyViewP[1] - stickyScrollerP[1]); return stickyData.getHostView(); } else { stickyData.setStickyOffset(0); } } return null; } @Override public boolean handleMessage(Message msg) { switch (msg.what) { case 0: if (mScrollerTask != null) { mScrollerTask.removeMessages(0); } int newPosition = getScrollY(); if (mInitialPosition - newPosition == 0) {//has stopped onScrollStopped(WXScrollView.this, getScrollX(), getScrollY()); } else { onScroll(WXScrollView.this, getScrollX(), getScrollY()); mInitialPosition = getScrollY(); if (mScrollerTask != null) { mScrollerTask.sendEmptyMessageDelayed(0, mCheckTime); } } break; default: break; } return true; } protected void onScrollStopped(WXScrollView scrollView, int x, int y) { int count = mScrollViewListeners == null ? 0 : mScrollViewListeners.size(); for (int i = 0; i < count; ++i) { mScrollViewListeners.get(i).onScrollStopped(this, x, y); } } @Override public void destroy() { if (mScrollerTask != null) { mScrollerTask.removeCallbacksAndMessages(null); } } @Override public void registerGestureListener(WXGesture wxGesture) { this.wxGesture = wxGesture; } public Rect getContentFrame() { return new Rect(0, 0, computeHorizontalScrollRange(), computeVerticalScrollRange()); } public interface WXScrollViewListener { void onScrollChanged(WXScrollView scrollView, int x, int y, int oldx, int oldy); void onScrollToBottom(WXScrollView scrollView, int x, int y); void onScrollStopped(WXScrollView scrollView, int x, int y); void onScroll(WXScrollView scrollView, int x, int y); } public void setWAScroller(WXScroller mWAScroller) { this.mWAScroller = mWAScroller; } }