Java tutorial
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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.component; import android.content.Context; import android.support.annotation.NonNull; import android.support.v4.view.ViewPager; import android.text.TextUtils; import android.view.Gravity; import android.view.View; import android.view.ViewGroup; import android.widget.FrameLayout; import com.taobao.weex.WXSDKInstance; import com.taobao.weex.WXSDKManager; import com.taobao.weex.common.WXThread; import com.taobao.weex.dom.WXDomManager; import com.taobao.weex.dom.WXDomObject; import com.taobao.weex.ui.ComponentCreator; import com.taobao.weex.ui.view.WXCircleIndicator; import com.taobao.weex.ui.view.WXCirclePageAdapter; import com.taobao.weex.ui.view.WXCircleViewPager; import com.taobao.weex.utils.WXUtils; import com.taobao.weex.utils.WXViewUtils; import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.util.List; import java.util.concurrent.ConcurrentHashMap; /** * Known Issus: In auto play mode, neighbor view not scaled or aplhaed rarely. * * Created by xingjiu on 16/8/18. */ public class WXSliderNeighbor extends WXSlider { public static final String NEIGHBOR_SCALE = "neighborScale"; // the init scale of neighbor page public static final String NEIGHBOR_ALPHA = "neighborAlpha"; // the init alpha of neighbor page public static final String NEIGHBOR_SPACE = "neighborSpace"; // the init space of neighbor page private static final int DEFAULT_NEIGHBOR_SPACE = 25; private static final float DEFAULT_NEIGHBOR_SCALE = 0.8F; private static final float DEFAULT_NEIGHBOR_ALPHA = 0.6F; private float mNeighborScale = DEFAULT_NEIGHBOR_SCALE; private float mNeighborAlpha = DEFAULT_NEIGHBOR_ALPHA; private float mNeighborSpace = DEFAULT_NEIGHBOR_SPACE; private static final float WX_DEFAULT_MAIN_NEIGHBOR_SCALE = 0.9f; private ZoomTransformer mCachedTransformer; public WXSliderNeighbor(WXSDKInstance instance, WXDomObject node, WXVContainer parent) { super(instance, node, parent); } public static class Creator implements ComponentCreator { public WXComponent createInstance(WXSDKInstance instance, WXDomObject node, WXVContainer parent) throws IllegalAccessException, InvocationTargetException, InstantiationException { return new WXSliderNeighbor(instance, node, parent); } } @Override public void bindData(WXComponent component) { super.bindData(component); } @Override protected FrameLayout initComponentHostView(@NonNull Context context) { FrameLayout view = new FrameLayout(context); // init view pager FrameLayout.LayoutParams pagerParams = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT); pagerParams.gravity = Gravity.CENTER; mViewPager = new WXCircleViewPager(getContext()); mViewPager.setLayoutParams(pagerParams); // init adapter mAdapter = new WXCirclePageAdapter(); mViewPager.setAdapter(mAdapter); // add to parent view.addView(mViewPager); mViewPager.addOnPageChangeListener(mPageChangeListener); mViewPager.setOverScrollMode(View.OVER_SCROLL_NEVER); registerActivityStateListener(); mViewPager.setPageTransformer(false, createTransformer()); return view; } ZoomTransformer createTransformer() { if (mCachedTransformer == null) { mCachedTransformer = new ZoomTransformer(); } return mCachedTransformer; } @Override protected void addSubView(View view, final int index) { if (view == null || mAdapter == null) { return; } if (view instanceof WXCircleIndicator) { return; } FrameLayout wrapper = new FrameLayout(getContext()); FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT); params.gravity = Gravity.CENTER; view.setLayoutParams(params); wrapper.addView(view); super.addSubView(wrapper, index); updateAdapterScaleAndAlpha(mNeighborAlpha, mNeighborScale); // we need to set neighbor view status when added. mViewPager.postDelayed(WXThread.secure(new Runnable() { @Override public void run() { try { if (mViewPager.getRealCount() > 0 && index > 2) { // index > 2 mean more than two times, then need a fake drag // prevent a bug of init status. ZoomTransformer no called as excepted. mViewPager.beginFakeDrag(); mViewPager.fakeDragBy(1); // must be 1 } } catch (IndexOutOfBoundsException e) { // do nothing } finally { try { mViewPager.endFakeDrag(); } catch (Exception e) { // do nothing } } } }), 50); } private void updateScaleAndAlpha(View view, float alpha, float scale) { if (null == view) { return; } if (alpha >= 0 && view.getAlpha() != alpha) { view.setAlpha(alpha); } if (scale >= 0 && view.getScaleX() != scale) { view.setScaleX(scale); view.setScaleY(scale); } } private void updateAdapterScaleAndAlpha(final float alpha, final float scale) { final List<View> pageViews = mAdapter.getViews(); final int curPos = mViewPager.getCurrentItem(); if (pageViews.size() > 0) { final View currentPage = pageViews.get(curPos); updateScaleAndAlpha(((ViewGroup) currentPage).getChildAt(0), 1.0F, WX_DEFAULT_MAIN_NEIGHBOR_SCALE); if (pageViews.size() < 2) { return; } //make sure View's width & height are measured. currentPage.post(WXThread.secure(new Runnable() { @Override public void run() { //change left and right page's translation updateNeighbor(currentPage, alpha, scale); } })); // make sure only display view current, left, right. int left = (curPos == 0) ? pageViews.size() - 1 : curPos - 1; int right = (curPos == pageViews.size() - 1) ? 0 : curPos + 1; for (int i = 0; i < mAdapter.getRealCount(); i++) { if (i != left && i != curPos && i != right) { ((ViewGroup) pageViews.get(i)).getChildAt(0).setAlpha(0F); } } } } private void updateNeighbor(View currentPage, final float alpha, final float scale) { final List<View> pageViews = mAdapter.getViews(); final int curPos = mViewPager.getCurrentItem(); float translation = calculateTranslation(currentPage); int left = (curPos == 0) ? pageViews.size() - 1 : curPos - 1; View leftPage = pageViews.get(left); int right = (curPos == pageViews.size() - 1) ? 0 : curPos + 1; View rightPage = pageViews.get(right); if (pageViews.size() == 2) { if (curPos == 0) { moveRight(rightPage, translation, alpha, scale); } else if (curPos == 1) { moveLeft(leftPage, translation, alpha, scale); } } else { moveLeft(leftPage, translation, alpha, scale); moveRight(rightPage, translation, alpha, scale); } } private void moveLeft(View page, float translation, float alpha, float scale) { updateScaleAndAlpha(((ViewGroup) page).getChildAt(0), alpha, scale); page.setTranslationX(translation); ((ViewGroup) page).getChildAt(0).setTranslationX(translation); } private void moveRight(View page, float translation, float alpha, float scale) { moveLeft(page, -translation, alpha, scale); } @WXComponentProp(name = NEIGHBOR_SCALE) public void setNeighborScale(String input) { float neighborScale = DEFAULT_NEIGHBOR_SCALE; if (!TextUtils.isEmpty(input)) { try { neighborScale = Float.parseFloat(input); } catch (NumberFormatException e) { } } // addSubView is called before setProperty, so we need to modify the neighbor view in mAdapter. if (this.mNeighborScale != neighborScale) { this.mNeighborScale = neighborScale; updateAdapterScaleAndAlpha(-1, neighborScale); } } @WXComponentProp(name = NEIGHBOR_ALPHA) public void setNeighborAlpha(String input) { float neighborAlpha = DEFAULT_NEIGHBOR_ALPHA; if (!TextUtils.isEmpty(input)) { try { neighborAlpha = Float.parseFloat(input); } catch (NumberFormatException e) { } } // The same work as setNeighborScale() if (this.mNeighborAlpha != neighborAlpha) { this.mNeighborAlpha = neighborAlpha; updateAdapterScaleAndAlpha(neighborAlpha, -1); } } @WXComponentProp(name = NEIGHBOR_SPACE) @SuppressWarnings("unused") public void setNeighborSpace(String input) { float neighborSpace = DEFAULT_NEIGHBOR_SPACE; if (!TextUtils.isEmpty(input)) { try { neighborSpace = Float.parseFloat(input); } catch (NumberFormatException e) { } } if (this.mNeighborSpace != neighborSpace) { this.mNeighborSpace = neighborSpace; } } @Override protected boolean setProperty(String key, Object param) { String input; switch (key) { case NEIGHBOR_SCALE: input = WXUtils.getString(param, null); if (input != null) { setNeighborScale(input); } return true; case NEIGHBOR_ALPHA: input = WXUtils.getString(param, null); if (input != null) { setNeighborAlpha(input); } return true; case NEIGHBOR_SPACE: input = WXUtils.getString(param, null); if (input != null) { setNeighborSpace(input); } return true; } return super.setProperty(key, param); } /** * we need add translation for left and right card view. * */ private float calculateTranslation(@NonNull View hostPage) { if (!(hostPage instanceof ViewGroup)) { return 0; } View realView = ((ViewGroup) hostPage).getChildAt(0); float translation = (hostPage.getMeasuredWidth() - realView.getMeasuredWidth() * mNeighborScale) / 4; translation += ((hostPage.getMeasuredWidth() - realView.getMeasuredWidth() * WX_DEFAULT_MAIN_NEIGHBOR_SCALE) / 2 - WXViewUtils.getRealPxByWidth(mNeighborSpace)) / 2; return translation; } // Here is the trick. class ZoomTransformer implements ViewPager.PageTransformer { @Override public void transformPage(View page, float position) { int pagePosition = mAdapter.getPagePosition(page); int curPosition = mViewPager.getCurrentItem(); int realCount = mAdapter.getRealCount(); boolean ignore = false; if (curPosition != 0 && curPosition != realCount - 1 && Math.abs(pagePosition - curPosition) > 1) { ignore = true; } if (curPosition == 0 && pagePosition < realCount - 1 && pagePosition > 1) { ignore = true; } if (curPosition == realCount - 1 && pagePosition < realCount - 2 && pagePosition > 0) { ignore = true; } // just transfer the neighbor(left & right) page. if (ignore) { return; } View realView = ((ViewGroup) page).getChildAt(0); if (realView == null) { return; } float alpha, scale; if (position <= (-realCount + 1)) { position = position + realCount; } if (position >= realCount - 1) { position = position - realCount; } if (position >= -1 && position <= 1) { float factor = Math.abs(Math.abs(position) - 1); scale = mNeighborScale + factor * (WX_DEFAULT_MAIN_NEIGHBOR_SCALE - mNeighborScale); alpha = (1 - mNeighborAlpha) * factor + mNeighborAlpha; float translation = calculateTranslation(page); if (position > 0) { translation = (position * translation); realView.setTranslationX(-translation); page.setTranslationX(-translation); } else if (position == 0) { page.setTranslationX(0); realView.setTranslationX(0); updateAdapterScaleAndAlpha(mNeighborAlpha, mNeighborScale); } else { if (realCount == 2 && Math.abs(position) == 1) { return; } translation = (-position * translation); realView.setTranslationX(translation); page.setTranslationX(translation); } realView.setScaleX(scale); realView.setScaleY(scale); realView.setAlpha(alpha); } } } }