Android 基于RecycledView的实现画廊控件.zip

package com.yao.cardgallery; import android.content.Context; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import android.util.AttributeSet; import android.view.View; import android.view.ViewGroup; import java.util.ArrayList; import java.util.List; /** * Created by Yao */ public class CardGalleryView extends RecyclerView { //CardGalleryView适配器 private Adapter<?> wrapperAdapter; //当前item的索引 private int currentIndex = 0; //改变选中的监听器集合 private List<OnPageChangedListener> mOnPageChangedListeners; //缩放的系数 private int scaleMultiple = 10; public CardGalleryView(Context context) { super(context); init(); } public CardGalleryView(Context context, AttributeSet attrs) { super(context, attrs); init(); } public CardGalleryView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } @Override public void setAdapter(RecyclerView.Adapter adapter) { wrapperAdapter = transformCardGalleryAdapter(adapter); super.setAdapter(wrapperAdapter); initPosition(); } @Override public void swapAdapter(RecyclerView.Adapter adapter, boolean removeAndRecycleExistingViews) { wrapperAdapter = transformCardGalleryAdapter(adapter); super.swapAdapter(wrapperAdapter, removeAndRecycleExistingViews); initPosition(); } @Override public RecyclerView.Adapter getAdapter() { if (wrapperAdapter != null) { return wrapperAdapter.adapter; } return null; } /** * 获取包装的Adapter * * @return */ public Adapter getWrapperAdapter() { return wrapperAdapter; } /** * 初始化item位置 */ private void initPosition() { scrollToPosition(getMiddlePosition()); new Thread() { @Override public void run() { while (getChildAt(0) == null) ; post(new Runnable() { @Override public void run() { alignView(0); } }); } }.start(); } /** * 转换为CardGallery.Adapter * * @param adapter * @return */ protected Adapter transformCardGalleryAdapter(RecyclerView.Adapter adapter) { return (adapter instanceof Adapter) ? (Adapter) adapter : new Adapter(this, adapter); } private void init() { setLayoutManager(new LinearLayoutManager(getContext(), LinearLayoutManager.HORIZONTAL, false));//设置横向滚动 setHorizontalScrollBarEnabled(false);//隐藏滚动条 //添加滚动监听 addOnScrollListener(new RecyclerView.OnScrollListener() { @Override public void onScrollStateChanged(RecyclerView recyclerView, int newState) { super.onScrollStateChanged(recyclerView, newState); if (newState == SCROLL_STATE_IDLE) {//停止滚动 int newIndex = getItem4ScreenXMin();//获取最靠近中线的Item索引 if (mOnPageChangedListeners != null) {//触发监听器 for (OnPageChangedListener onPageChangedListener : mOnPageChangedListeners) { if (onPageChangedListener != null) { onPageChangedListener.OnPageChanged(getActualCurrentIndex(), getChildAt(newIndex).getId()); } } } alignView(newIndex);//Item对齐 } } @Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) { super.onScrolled(recyclerView, dx, dy); int screenX = getView4ScreenX(CardGalleryView.this); for (int i = 0; i < getChildCount(); i++) { View view = getChildAt(i); int height = view.getHeight(); int width = view.getWidth(); int difference = Math.abs(screenX - getView4ScreenX(view));//item与recyclerView的距离 int padding = difference / scaleMultiple; view.setPadding(padding, (int) (padding * (float) height / width), padding, (int) (padding * (float) height / width)); view.getLayoutParams().height = height;//保持item高度不变 view.requestLayout(); //快速滚动时可能没有difference==0的情况，所以这里用difference <= 100来触发选中Item if (difference <= 100) { if (mOnPageChangedListeners != null) {//触发监听器 for (OnPageChangedListener onPageChangedListener : mOnPageChangedListeners) { if (onPageChangedListener != null) { onPageChangedListener.OnPageChanged(getActualCurrentIndex(), view.getId()); } } } currentIndex = i; } } } }); } public int getScaleMultiple() { return scaleMultiple; } public void setScaleMultiple(int scaleMultiple) { this.scaleMultiple = scaleMultiple; } /** * 根据索引居中item * * @param newIndex */ private void alignView(int newIndex) { currentIndex = newIndex; alignView(getChildAt(newIndex)); } /** * 居中view * * @param view */ private void alignView(View view) { int dx = getView4ScreenX(CardGalleryView.this) - getView4ScreenX(view); smoothScrollBy(-dx, 0); } //获取当前item真实索引 public int getActualCurrentIndex() { return getChildAt(currentIndex).getId(); } /** * 获取真实的item数 * * @return */ private int getActualItemCountFromAdapter() { return (getWrapperAdapter()).getActualItemCount(); } private int getMiddlePosition() { int middlePosition = Integer.MAX_VALUE / 2; final int actualItemCount = getActualItemCountFromAdapter(); if (actualItemCount > 0 && middlePosition % actualItemCount != 0) { middlePosition = middlePosition - middlePosition % actualItemCount; } return middlePosition; } /** * 获取距离RecyclerView中线最接近item的索引 * * @return */ private int getItem4ScreenXMin() { int screenX = getView4ScreenX(this); int min = 10086; int item = 0; for (int i = 0; i < getChildCount(); i++) { int difference = screenX - getView4ScreenX(getChildAt(i)); if (Math.abs(min) > Math.abs(difference)) { min = difference; item = i; } } return item; } /** * 获取view中线相对于屏幕的x坐标 * * @param view * @return */ private int getView4ScreenX(View view) { int w = view.getWidth(); int[] location = new int[2]; view.getLocationOnScreen(location); return w / 2 + location[0]; } public static class Adapter<VH extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<VH> implements View.OnClickListener { RecyclerView.Adapter<VH> adapter; CardGalleryView cardGalleryView; View.OnClickListener onClickListener;//当前选中item的点击监听器 int itemWidth;//item的宽度 public Adapter(final CardGalleryView cardGalleryView, RecyclerView.Adapter adapter) { this.adapter = adapter; this.car