来自 技术 2019-04-17 的文章

android -------- RecyclerView的可(多个Item水平,垂直

八年Java开发的感悟:什么才是程序员的立身之本>>>   

RecyclerView的可滚动的列表实现,视图相邻的视图在屏幕上部分或完全可见(水平3个item,第一个和第三个显示一部分,第二个完全显示)

效果如图:

基于RecyclerView完成的(自定义控件)

public class DiscreteRecyclerView extends RecyclerView { public static final int NO_POSITION = DiscreteRecyclerLayoutManager.NO_POSITION; private static final int DEFAULT_ORIENTATION = DSVOrientation.HORIZONTAL.ordinal(); private DiscreteRecyclerLayoutManager layoutManager; private List<ScrollStateChangeListener> scrollStateChangeListeners; private List<OnItemChangedListener> onItemChangedListeners; private boolean isOverScrollEnabled; public DiscreteRecyclerView(Context context) { super(context); init(null); } public DiscreteRecyclerView(Context context, AttributeSet attrs) { super(context, attrs); init(attrs); } public DiscreteRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(attrs); } private void init(AttributeSet attrs) { scrollStateChangeListeners = new ArrayList<>(); onItemChangedListeners = new ArrayList<>(); int orientation = DEFAULT_ORIENTATION; if (attrs != null) { TypedArray ta = getContext().obtainStyledAttributes(attrs, R.styleable.DiscreteRecyclerView); orientation = ta.getInt(R.styleable.DiscreteRecyclerView_dsv_orientation, DEFAULT_ORIENTATION); ta.recycle(); } isOverScrollEnabled = getOverScrollMode() != OVER_SCROLL_NEVER; layoutManager = new DiscreteRecyclerLayoutManager( getContext(), new ScrollStateListener(), DSVOrientation.values()[orientation]); setLayoutManager(layoutManager); } @Override public void setLayoutManager(LayoutManager layout) { if (layout instanceof DiscreteRecyclerLayoutManager) { super.setLayoutManager(layout); } else { throw new IllegalArgumentException(getContext().getString(R.string.dsv_ex_msg_dont_set_lm)); } } @Override public boolean fling(int velocityX, int velocityY) { boolean isFling = super.fling(velocityX, velocityY); if (isFling) { layoutManager.onFling(velocityX, velocityY); } else { layoutManager.returnToCurrentPosition(); } return isFling; } @Nullable public ViewHolder getViewHolder(int position) { View view = layoutManager.findViewByPosition(position); return view != null ? getChildViewHolder(view) : null; } /** * @return adapter position of the current item or -1 if nothing is selected */ public int getCurrentItem() { return layoutManager.getCurrentPosition(); } public void setItemTransformer(DiscreteScrollItemTransformer transformer) { layoutManager.setItemTransformer(transformer); } public void setItemTransitionTimeMillis(@IntRange(from = 10) int millis) { layoutManager.setTimeForItemSettle(millis); } public void setSlideOnFling(boolean result){ layoutManager.setShouldSlideOnFling(result); } public void setSlideOnFlingThreshold(int threshold){ layoutManager.setSlideOnFlingThreshold(threshold); } public void setOrientation(DSVOrientation orientation) { layoutManager.setOrientation(orientation); } public void setOffscreenItems(int items) { layoutManager.setOffscreenItems(items); } public void setClampTransformProgressAfter(@IntRange(from = 1) int itemCount) { if (itemCount <= 1) { throw new IllegalArgumentException("must be >= 1"); } layoutManager.setTransformClampItemCount(itemCount); } public void setOverScrollEnabled(boolean overScrollEnabled) { isOverScrollEnabled = overScrollEnabled; setOverScrollMode(OVER_SCROLL_NEVER); } public void addScrollStateChangeListener(@NonNull ScrollStateChangeListener<?> scrollStateChangeListener) { scrollStateChangeListeners.add(scrollStateChangeListener); } public void addScrollListener(@NonNull ScrollListener<?> scrollListener) { addScrollStateChangeListener(new ScrollListenerAdapter(scrollListener)); } public void addOnItemChangedListener(@NonNull OnItemChangedListener<?> onItemChangedListener) { onItemChangedListeners.add(onItemChangedListener); } public void removeScrollStateChangeListener(@NonNull ScrollStateChangeListener<?> scrollStateChangeListener) { scrollStateChangeListeners.remove(scrollStateChangeListener); } public void removeScrollListener(@NonNull ScrollListener<?> scrollListener) { removeScrollStateChangeListener(new ScrollListenerAdapter<>(scrollListener)); } public void removeItemChangedListener(@NonNull OnItemChangedListener<?> onItemChangedListener) { onItemChangedListeners.remove(onItemChangedListener); } private void notifyScrollStart(ViewHolder holder, int current) { for (ScrollStateChangeListener listener : scrollStateChangeListeners) { listener.onScrollStart(holder, current); } } private void notifyScrollEnd(ViewHolder holder, int current) { for (ScrollStateChangeListener listener : scrollStateChangeListeners) { listener.onScrollEnd(holder, current); } } private void notifyScroll(float position, int currentIndex, int newIndex, ViewHolder currentHolder, ViewHolder newHolder) { for (ScrollStateChangeListener listener : scrollStateChangeListeners) { listener.onScroll(position, currentIndex, newIndex, currentHolder, newHolder); } } private void notifyCurrentItemChanged(ViewHolder holder, int current) { for (OnItemChangedListener listener : onItemChangedListeners) { listener.onCurrentItemChanged(holder, current); } } private void notifyCurrentItemChanged() { if (onItemChangedListeners.isEmpty()) { return; } int current = layoutManager.getCurrentPosition(); ViewHolder currentHolder = getViewHolder(current); notifyCurrentItemChanged(currentHolder, current); } private class ScrollStateListener implements DiscreteRecyclerLayoutManager.ScrollStateListener { @Override public void onIsBoundReachedFlagChange(boolean isBoundReached) { if (isOverScrollEnabled) { setOverScrollMode(isBoundReached ? OVER_SCROLL_ALWAYS : OVER_SCROLL_NEVER); } } @Override public void onScrollStart() { if (scrollStateChangeListeners.isEmpty()) { return; } int current = layoutManager.getCurrentPosition(); ViewHolder holder = getViewHolder(current); if (holder != null) { notifyScrollStart(holder, current); } } @Override public void onScrollEnd() { if (onItemChangedListeners.isEmpty() && scrollStateChangeListeners.isEmpty()) { return; } int current = layoutManager.getCurrentPosition(); ViewHolder holder = getViewHolder(current); if (holder != null) { notifyScrollEnd(holder, current); notifyCurrentItemChanged(holder, current); } } @Override public void onScroll(float currentViewPosition) { if (scrollStateChangeListeners.isEmpty()) { return; } int currentIndex = getCurrentItem(); int newIndex = layoutManager.getNextPosition(); if (currentIndex != newIndex) { notifyScroll(currentViewPosition, currentIndex, newIndex, getViewHolder(currentIndex), getViewHolder(newIndex)); } } @Override public void onCurrentViewFirstLayout() { post(new Runnable() { @Override public void run() { notifyCurrentItemChanged(); } }); } @Override public void onDataSetChangeChangedPosition() { notifyCurrentItemChanged(); } } public interface ScrollStateChangeListener<T extends ViewHolder> { void onScrollStart(@NonNull T currentItemHolder, int adapterPosition); void onScrollEnd(@NonNull T currentItemHolder, int adapterPosition); void onScroll(float scrollPosition, int currentPosition, int newPosition, @Nullable T currentHolder, @Nullable T newCurrent); } public interface ScrollListener<T extends ViewHolder> { void onScroll(float scrollPosition, int currentPosition, int newPosition, @Nullable T currentHolder, @Nullable T newCurrent); } public interface OnItemChangedListener<T extends ViewHolder> { /* * This method will be also triggered when view appears on the screen for the first time. * If data set is empty, viewHolder will be null and adapterPosition will be NO_POSITION */ void onCurrentItemChanged(@Nullable T viewHolder, int adapterPosition); }}

源码:https://github.com/DickyQie/android-discrete-recyclerview

标签:   Android      linux 状态      linux文件解压   
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