700字范文 > Android中实现类似探探中图片左右滑动切换效果

Android中实现类似探探中图片左右滑动切换效果

时间：2018-11-06 09:38:02

偶然之间发现探探的左右滑动的图片挺好玩，试着去做了下，再到后来，看到许多大神也推出了同样仿探探效果的博客，从头到尾阅读下来，写得通俗易懂，基本上没什么问题。于是，实现仿探探效果的想法再次出现在脑海中。那么，还犹豫什么，趁热来一发吧!就这么愉快地决定了。

RecyclerView 是最佳选择!

重要的话讲三遍!!!

究其原因，第一，RecyclerView 是自带 Item View 回收和重用功能的，就不需要我们考虑这个问题了;第二，RecyclerView 的布局方式是通过设置 LayoutManager 来实现的，这样就充分地把布局和 RecyclerView “解耦”开来了。而 LayoutManager 是可以通过自定义的方式来实现的。这恰恰是我们想要的!!!再说一点，这也正是不选用 ListView 的原因之一。

下面，我们就开始动手了。带你见证奇迹的时刻。

1.创建 CardLayoutManager 并继承自 RecyclerView.LayoutManager 。需要我们自己实现 generateDefaultLayoutParams() 方法：

@Overridepublic RecyclerView.LayoutParams generateDefaultLayoutParams() {

return new RecyclerView.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,ViewGroup.LayoutParams.WRAP_CONTENT);}

2.一般情况下，像上面这样写即可。

下面这个方法就是我们的重点了。 onLayoutChildren(final RecyclerView.Recycler recycler, RecyclerView.State state) 方法就是用来实现 Item View 布局的：

@Overridepublic void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {

super.onLayoutChildren(recycler, state);removeAllViews();detachAndScrapAttachedViews(recycler);

int itemCount = getItemCount();

if(itemCount>CardConfig.DEFAULT_SHOW_ITEM){

for(int position = CardConfig.DEFAULT_SHOW_ITEM;position>=0;position--){

final View view = recycler.getViewForPosition(position);addView(view);measureChildWithMargins(view,0,0);

int widthSpace = getWidth() -getDecoratedMeasuredWidth(view);

int heightSpace = getHeight() - getBottomDecorationHeight(view);layoutDecoratedWithMargins(view,widthSpace/2,heightSpace/2,widthSpace/2+getDecoratedMeasuredWidth(view),heightSpace/2+getBottomDecorationHeight(view));

if(position == CardConfig.DEFAULT_SHOW_ITEM){view.setScaleX(1-(position-1)*CardConfig.DEFAULT_SCALE);view.setScaleY(1-(position-1)*CardConfig.DEFAULT_SCALE);view.setTranslationY((position-1)*view.getMeasuredHeight()/CardConfig.DEFAULT_TRANSLATE_Y);}else if(position>0){view.setScaleX(1 - position * CardConfig.DEFAULT_SCALE);view.setScaleY(1 - position * CardConfig.DEFAULT_SCALE);view.setTranslationY(position * view.getMeasuredHeight() / CardConfig.DEFAULT_TRANSLATE_Y);}else{view.setOnTouchListener(mOnTouchListener);}}}else{

// 当数据源个数小于或等于最大显示数时for (int position = itemCount - 1; position >= 0; position--) {

final View view = recycler.getViewForPosition(position);addView(view);measureChildWithMargins(view, 0, 0);

int widthSpace = getWidth() - getDecoratedMeasuredWidth(view);

int heightSpace = getHeight() - getDecoratedMeasuredHeight(view);

// recyclerview 布局layoutDecoratedWithMargins(view, widthSpace / 2, heightSpace / 2,widthSpace / 2 + getDecoratedMeasuredWidth(view),heightSpace / 2 + getDecoratedMeasuredHeight(view));

if (position > 0) {view.setScaleX(1 - position * CardConfig.DEFAULT_SCALE);view.setScaleY(1 - position * CardConfig.DEFAULT_SCALE);view.setTranslationY(position * view.getMeasuredHeight() / CardConfig.DEFAULT_TRANSLATE_Y);} else {view.setOnTouchListener(mOnTouchListener);}}}}

3.创建onTouchListener

private View.OnTouchListener mOnTouchListener = new View.OnTouchListener() {

@Overridepublic boolean onTouch(View v, MotionEvent event) {RecyclerView.ViewHolder childViewHolder = mRecyclerView.getChildViewHolder(v);

if (MotionEventCompat.getActionMasked(event) == MotionEvent.ACTION_DOWN) {mItemTouchHelper.startSwipe(childViewHolder);}

return false;}};

4.完整CardLayoutManager代码如下

public class CardLayoutManager extends RecyclerView.LayoutManager {

private RecyclerView mRecyclerView;

private ItemTouchHelper mItemTouchHelper;

public CardLayoutManager(@NonNull RecyclerView recyclerView, @NonNull ItemTouchHelper itemTouchHelper) {

this.mRecyclerView = recyclerView;

this.mItemTouchHelper = itemTouchHelper;}