我有一个RecyclerView，方向为HORIZONTAL。我想自动从右向左滚动RecyclerView。
另外，我需要以下选项
应无限循环滚动
在自动滚动时支持触摸
支持反向自动滚动（从左到右）
应该在所有布局管理器（LinearLayoutManager，GridLayoutManager，StaggeredGridLayoutManager）中工作
答案 0 :(得分：0)
最后，我找到了使用所有选项的上述问题的解决方案。
开始自动滚动
recyclerView.startAutoScroll();
无限循环
recyclerView.setLoopEnabled(true);
触摸
recyclerView.setCanTouch(true);
用于暂停自动滚动
recyclerView.pauseAutoScroll(true);
它将与所有版式管理器（LinearLayoutManager，GridLayoutManager，StaggeredGridLayoutManager）一起使用
AutoScrollRecyclerView
public class AutoScrollRecyclerView extends RecyclerView {
private static final String TAG = AutoScrollRecyclerView.class.getSimpleName();
private static final int SPEED = 10;
/**
* Sliding estimator
*/
private UniformSpeedInterpolator mInterpolator;
/**
* Dx and dy between units
*/
private int mSpeedDx, mSpeedDy;
/**
* Sliding speed, default 100
*/
private int mCurrentSpeed = SPEED;
/**
* Whether to display the list infinitely
*/
private boolean mLoopEnabled;
/**
* Whether to slide backwards
*/
private boolean mReverse;
/**
* Whether to turn on automatic sliding
*/
private boolean mIsOpenAuto;
/**
* Whether the user can manually slide the screen
*/
private boolean mCanTouch = true;
/**
* Whether the user clicks on the screen
*/
private boolean mPointTouch;
/**
* Are you ready for data?
*/
private boolean mReady;
/**
* Whether initialization is complete
*/
private boolean mInflate;
/**
* Whether to stop scroll
*/
private boolean isStopAutoScroll = false;
public AutoScrollRecyclerView(Context context) {
this(context, null);
}
public AutoScrollRecyclerView(Context context, @Nullable AttributeSet attrs) {
this(context, attrs, 0);
}
public AutoScrollRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mInterpolator = new UniformSpeedInterpolator();
mReady = false;
}
/**
* Start sliding
*/
public void startAutoScroll() {
isStopAutoScroll = false;
openAutoScroll(mCurrentSpeed, false);
}
/**
* Start sliding
*
* @param speed Sliding distance (determining the sliding speed)
* @param reverse Whether to slide backwards
*/
public void openAutoScroll(int speed, boolean reverse) {
mReverse = reverse;
mCurrentSpeed = speed;
mIsOpenAuto = true;
notifyLayoutManager();
startScroll();
}
/**
* Is it possible to manually slide when swiping automatically?
*/
public void setCanTouch(boolean b) {
mCanTouch = b;
}
public boolean canTouch() {
return mCanTouch;
}
/**
* Set whether to display the list infinitely
*/
public void setLoopEnabled(boolean loopEnabled) {
this.mLoopEnabled = loopEnabled;
if (getAdapter() != null) {
getAdapter().notifyDataSetChanged();
startScroll();
}
}
/**
* Whether to slide infinitely
*/
public boolean isLoopEnabled() {
return mLoopEnabled;
}
/**
* Set whether to reverse
*/
public void setReverse(boolean reverse) {
mReverse = reverse;
notifyLayoutManager();
startScroll();
}
/**
* @param isStopAutoScroll
*/
public void pauseAutoScroll(boolean isStopAutoScroll) {
this.isStopAutoScroll = isStopAutoScroll;
}
public boolean getReverse() {
return mReverse;
}
/**
* Start scrolling
*/
private void startScroll() {
if (!mIsOpenAuto)
return;
if (getScrollState() == SCROLL_STATE_SETTLING)
return;
if (mInflate && mReady) {
mSpeedDx = mSpeedDy = 0;
smoothScroll();
}
}
private void smoothScroll() {
if (!isStopAutoScroll) {
int absSpeed = Math.abs(mCurrentSpeed);
int d = mReverse ? -absSpeed : absSpeed;
smoothScrollBy(d, d, mInterpolator);
}
}
private void notifyLayoutManager() {
LayoutManager layoutManager = getLayoutManager();
if (layoutManager instanceof LinearLayoutManager) {
LinearLayoutManager linearLayoutManager = ((LinearLayoutManager) layoutManager);
if (linearLayoutManager != null) {
linearLayoutManager.setReverseLayout(mReverse);
}
} else {
StaggeredGridLayoutManager staggeredGridLayoutManager = ((StaggeredGridLayoutManager) layoutManager);
if (staggeredGridLayoutManager != null) {
staggeredGridLayoutManager.setReverseLayout(mReverse);
}
}
}
@Override
public void swapAdapter(Adapter adapter, boolean removeAndRecycleExistingViews) {
super.swapAdapter(generateAdapter(adapter), removeAndRecycleExistingViews);
mReady = true;
}
@Override
public void setAdapter(Adapter adapter) {
super.setAdapter(generateAdapter(adapter));
mReady = true;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent e) {
if (mCanTouch) {
switch (e.getAction()) {
case MotionEvent.ACTION_DOWN:
mPointTouch = true;
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
if (mIsOpenAuto) {
return true;
}
}
return super.onInterceptTouchEvent(e);
} else return true;
}
@Override
public boolean onTouchEvent(MotionEvent e) {
if (mCanTouch) {
switch (e.getAction()) {
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
if (mIsOpenAuto) {
mPointTouch = false;
smoothScroll();
return true;
}
}
return super.onTouchEvent(e);
} else return true;
}
@Override
public boolean performClick() {
return super.performClick();
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
startScroll();
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
mInflate = true;
}
@Override
public void onScrolled(int dx, int dy) {
if (mPointTouch) {
mSpeedDx = 0;
mSpeedDy = 0;
return;
}
boolean vertical;
if (dx == 0) {//Vertical scrolling
mSpeedDy += dy;
vertical = true;
} else {//Horizontal scrolling
mSpeedDx += dx;
vertical = false;
}
if (vertical) {
if (Math.abs(mSpeedDy) >= Math.abs(mCurrentSpeed)) {
mSpeedDy = 0;
smoothScroll();
}
} else {
if (Math.abs(mSpeedDx) >= Math.abs(mCurrentSpeed)) {
mSpeedDx = 0;
smoothScroll();
}
}
}
@NonNull
@SuppressWarnings("unchecked")
private NestingRecyclerViewAdapter generateAdapter(Adapter adapter) {
return new NestingRecyclerViewAdapter(this, adapter);
}
/**
* Custom estimator
* Swipe the list at a constant speed
*/
private static class UniformSpeedInterpolator implements Interpolator {
@Override
public float getInterpolation(float input) {
return input;
}
}
/**
* Customize the Adapter container so that the list can be displayed in an infinite loop
*/
private static class NestingRecyclerViewAdapter<VH extends RecyclerView.ViewHolder>
extends RecyclerView.Adapter<VH> {
private AutoScrollRecyclerView mRecyclerView;
RecyclerView.Adapter<VH> mAdapter;
NestingRecyclerViewAdapter(AutoScrollRecyclerView recyclerView, RecyclerView.Adapter<VH> adapter) {
mAdapter = adapter;
mRecyclerView = recyclerView;
}
@NonNull
@Override
public VH onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
return mAdapter.onCreateViewHolder(parent, viewType);
}
@Override
public void registerAdapterDataObserver(@NonNull RecyclerView.AdapterDataObserver observer) {
super.registerAdapterDataObserver(observer);
mAdapter.registerAdapterDataObserver(observer);
}
@Override
public void unregisterAdapterDataObserver(@NonNull RecyclerView.AdapterDataObserver observer) {
super.unregisterAdapterDataObserver(observer);
mAdapter.unregisterAdapterDataObserver(observer);
}
@Override
public void onBindViewHolder(@NonNull VH holder, int position) {
mAdapter.onBindViewHolder(holder, generatePosition(position));
}
@Override
public void setHasStableIds(boolean hasStableIds) {
super.setHasStableIds(hasStableIds);
mAdapter.setHasStableIds(hasStableIds);
}
@Override
public int getItemCount() {
//If it is an infinite scroll mode, set an unlimited number of items
return getLoopEnable() ? Integer.MAX_VALUE : mAdapter.getItemCount();
}
@Override
public int getItemViewType(int position) {
return mAdapter.getItemViewType(generatePosition(position));
}
@Override
public long getItemId(int position) {
return mAdapter.getItemId(generatePosition(position));
}
/**
* Returns the corresponding position according to the current scroll mode
*/
private int generatePosition(int position) {
if (getLoopEnable()) {
return getActualPosition(position);
} else {
return position;
}
}
/**
* Returns the actual position of the item
*
* @param position The position after starting to scroll will grow indefinitely
* @return Item actual location
*/
private int getActualPosition(int position) {
int itemCount = mAdapter.getItemCount();
return position >= itemCount ? position % itemCount : position;
}
private boolean getLoopEnable() {
return mRecyclerView.mLoopEnabled;
}
public boolean getReverse() {
return mRecyclerView.mReverse;
}
}
}