Android-->RecyclerView模仿探探左右
滑动布局
1:这种功能, 首先需要自己管理布局
继承 RecyclerView.LayoutManager , 显示自己管理布局, 比如最多显示4个view, 并且都是居中显示.
底部的View还需要进行缩放,平移操作.
public class OverLayCardLayoutManager extends RecyclerView.LayoutManager { private static final String TAG = \ public static int MAX_SHOW_COUNT = 4; public static float SCALE_GAP = 0.05f; public static int TRANS_Y_GAP;
public OverLayCardLayoutManager(Context context) { //平移时, 需要用到的参考值
TRANS_Y_GAP = (int) (20 * context.getResources().getDisplayMetrics().density); }
@Override
public RecyclerView.LayoutParams generateDefaultLayoutParams() { //必须要实现的方法
return new RecyclerView.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT); }
@Override
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) { //在这个方法中进行View的布局操作.此方法会被调用多次. detachAndScrapAttachedViews(recycler); int itemCount = getItemCount(); if (itemCount < 1) { return; }
//top-3View的position int bottomPosition; //边界处理
if (itemCount < MAX_SHOW_COUNT) { bottomPosition = 0; } else {
bottomPosition = itemCount - MAX_SHOW_COUNT; }
//从可见的最底层View开始layout，依次层叠上去
for (int position = bottomPosition; position < itemCount; position++) { //1:重recycler的缓存机制中拿到一个View
View view = recycler.getViewForPosition(position); //2:和自定义ViewGroup一样, 需要先addView addView(view);
//3:和自定义ViewGroup一样, 也需要测量View的大小 measureChildWithMargins(view, 0, 0);
int widthSpace = getWidth() - getDecoratedMeasuredWidth(view); int heightSpace = getHeight() - getDecoratedMeasuredHeight(view);
//4:和自定义ViewGroup的onLayout一样, 需要layout View.对View进行布局 //我们在布局时，将childView居中处理，这里也可以改为只水平居中 layoutDecoratedWithMargins(view, widthSpace / 2, heightSpace / 2, widthSpace / 2 + getDecoratedMeasuredWidth(view), heightSpace / 2 + getDecoratedMeasuredHeight(view)); /**
* TopView的Scale 为1，translationY 0
* 每一级Scale相差0.05f，translationY相差7dp左右 *
* 观察人人影视的UI，拖动时，topView被拖动，Scale不变，一直为1. * top-1View 的Scale慢慢变化至1，translation也慢慢恢复0
* top-2View的Scale慢慢变化至 top-1View的Scale，translation 也慢慢变化只top-1View的translation
* top-3View的Scale要变化，translation岿然不动 */
//第几层,举例子，count =7， 最后一个TopView（6）是第0层， int level = itemCount - position - 1;
//如果不需要缩放平移, 那么下面的代码可以注释掉... //除了顶层不需要缩小和位移
if (level > 0 /*&& level < mShowCount - 1*/) { //每一层都需要X方向的缩小
view.setScaleX(1 - SCALE_GAP * level); //前N层，依次向下位移和Y方向的缩小 if (level < MAX_SHOW_COUNT - 1) {
view.setTranslationY(TRANS_Y_GAP * level); view.setScaleY(1 - SCALE_GAP * level);
} else {//第N层在 向下位移和Y方向的缩小的成都与 N-1层保持一致 view.setTranslationY(TRANS_Y_GAP * (level - 1)); view.setScaleY(1 - SCALE_GAP * (level - 1)); } } }
} }
2:布局好了之后, 就需要监听鼠标事件了
谷歌官方提供了一个ItemTouchHelper工具类, 对滑动进行了惨无人道的优越封装, 傻x都能用…
使用方法: new ItemTouchHelper(callback).attachToRecyclerView(recyclerView);就这么简单, 接下来的操作, 都在回调callback里面进行.
public class RenRenCallback extends ItemTouchHelper.SimpleCallback {
private static final String TAG = \ private static final int MAX_ROTATION = 15; OnSwipeListener mSwipeListener; boolean isSwipeAnim = false;
public RenRenCallback() {
//第一个参数决定可以拖动排序的方向, 这里由于不需要拖动排序,所以传0 //第二个参数决定可以支持滑动的方向,这里设置了上下左右都可以滑动.
super(0, ItemTouchHelper.DOWN | ItemTouchHelper.UP | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT); }
public void setSwipeListener(OnSwipeListener swipeListener) { mSwipeListener = swipeListener; }
//水平方向是否可以被回收掉的阈值
public float getThreshold(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
//2016 12 26 考虑 探探垂直上下方向滑动，不删除卡片，这里参照源码写死0.5f return recyclerView.getWidth() * /*getSwipeThreshold(viewHolder)*/ 0.5f; }
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
//由于不支持滑动排序, 所以不需要处理此方法 return false; }
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) { //当view需要滑动的时候,会回调此方法
//但是这个方法只是告诉你View需要滑动, 并不是对View和Adapter进行额外的操作,
//所以, 如果你需要实现滑动删除, 那么需要在此方法中remove item等.
//我们这里需要对滑动过后的View,进行恢复操作.
viewHolder.itemView.setRotation(0);//恢复最后一次的旋转状态 if (mSwipeListener != null) {
mSwipeListener.onSwipeTo(viewHolder, 0); }
notifyListener(viewHolder.getAdapterPosition(), direction); }
private void notifyListener(int position, int direction) {
Log.w(TAG, \ if (mSwipeListener != null) {
mSwipeListener.onSwiped(position, direction); } }
@Override
public float getSwipeThreshold(RecyclerView.ViewHolder viewHolder) { //滑动的比例达到多少之后, 视为滑动 return 0.3f; }
@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, fwww.sm136.comloat dY, int actionState, boolean isCurrentlyActive) { super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
//当你在滑动的过程中, 此方法一直会被回调, 就跟onTouch事件一样... //先根据滑动的dx dy 算出现在动画的比例系数fraction float swipeValue = (float) Math.sqrt(dX * dX + dY * dY);
final float threshold = getThreshold(recyclerView, viewHolder); float fraction = swipeValue / threshold; //边界修正 最大为1 if (fraction > 1) { fraction = 1;
} else if (fraction < -1) { fraction = -1; }
//对每个ChildView进行缩放 位移
int childCount = recyclerView.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = recyclerView.getChildAt(i);
//第几层,举例子，count =7， 最后一个TopView（6）是第0层， int level = childCount - i - 1; if (level > 0) {
child.setScaleX(1 - SCALE_GAP * level + fraction * SCALE_GAP);
if (level < MAX_SHOW_COUNT - 1) {
child.setScaleY(1 - SCALE_GAP * level + fraction * SCALE_GAP); child.setTranslationY(TRANS_Y_GAP * level - fraction * TRANS_Y_GAP);
} else {
//child.setTranslationY((float) (mTranslationYGap * (level - 1) - fraction * mTranslationYGap)); } } else {
//最上层 //rotate
if (dX < -50) {
child.setRotation(-fraction * MAX_ROTATION); } else if (dX > 50) {
child.setRotation(fraction * MAX_ROTATION); } else {
child.setRotation(0); }
if (mSwipeListener != null) {
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
final int adapterPosition = params.getViewAdapterPosition();
mSwipeListener.onSwipeTo(recyclerView.findViewHolderForAdapterPosition(adapterPosition), dX);
} } } }
//扩展实现:点击按钮实现左滑效果
public void toLeft(RecyclerView recyclerView) { if (check(recyclerView)) {
animTo(recyclerView, false); } }