我曾经面临过同样的问题，并试图在网上找到解决方案。大多数解决方案采用两层方法（一个层次视图项，另一个层次按钮），但我想坚持只使用ItemTouchHelper。最终，我提出了一个可行的解决方案。请查看下面。
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.Rect;
import android.graphics.RectF;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Queue;
public abstract class SwipeHelper extends ItemTouchHelper.SimpleCallback {
public static final int BUTTON_WIDTH = YOUR_WIDTH_IN_PIXEL_PER_BUTTON
private RecyclerView recyclerView;
private List<UnderlayButton> buttons;
private GestureDetector gestureDetector;
private int swipedPos = -1;
private float swipeThreshold = 0.5f;
private Map<Integer, List<UnderlayButton>> buttonsBuffer;
private Queue<Integer> recoverQueue;
private GestureDetector.SimpleOnGestureListener gestureListener = new GestureDetector.SimpleOnGestureListener(){
@Override
public boolean onSingleTapConfirmed(MotionEvent e) {
for (UnderlayButton button : buttons){
if(button.onClick(e.getX(), e.getY()))
break;
}
return true;
}
};
private View.OnTouchListener onTouchListener = new View.OnTouchListener() {
@Override
public boolean onTouch(View view, MotionEvent e) {
if (swipedPos < 0) return false;
Point point = new Point((int) e.getRawX(), (int) e.getRawY());
RecyclerView.ViewHolder swipedViewHolder = recyclerView.findViewHolderForAdapterPosition(swipedPos);
View swipedItem = swipedViewHolder.itemView;
Rect rect = new Rect();
swipedItem.getGlobalVisibleRect(rect);
if (e.getAction() == MotionEvent.ACTION_DOWN || e.getAction() == MotionEvent.ACTION_UP ||e.getAction() == MotionEvent.ACTION_MOVE) {
if (rect.top < point.y && rect.bottom > point.y)
gestureDetector.onTouchEvent(e);
else {
recoverQueue.add(swipedPos);
swipedPos = -1;
recoverSwipedItem();
}
}
return false;
}
};
public SwipeHelper(Context context, RecyclerView recyclerView) {
super(0, ItemTouchHelper.LEFT);
this.recyclerView = recyclerView;
this.buttons = new ArrayList<>();
this.gestureDetector = new GestureDetector(context, gestureListener);
this.recyclerView.setOnTouchListener(onTouchListener);
buttonsBuffer = new HashMap<>();
recoverQueue = new LinkedList<Integer>(){
@Override
public boolean add(Integer o) {
if (contains(o))
return false;
else
return super.add(o);
}
};
attachSwipe();
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
int pos = viewHolder.getAdapterPosition();
if (swipedPos != pos)
recoverQueue.add(swipedPos);
swipedPos = pos;
if (buttonsBuffer.containsKey(swipedPos))
buttons = buttonsBuffer.get(swipedPos);
else
buttons.clear();
buttonsBuffer.clear();
swipeThreshold = 0.5f * buttons.size() * BUTTON_WIDTH;
recoverSwipedItem();
}
@Override
public float getSwipeThreshold(RecyclerView.ViewHolder viewHolder) {
return swipeThreshold;
}
@Override
public float getSwipeEscapeVelocity(float defaultValue) {
return 0.1f * defaultValue;
}
@Override
public float getSwipeVelocityThreshold(float defaultValue) {
return 5.0f * defaultValue;
}
@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
int pos = viewHolder.getAdapterPosition();
float translationX = dX;
View itemView = viewHolder.itemView;
if (pos < 0){
swipedPos = pos;
return;
}
if(actionState == ItemTouchHelper.ACTION_STATE_SWIPE){
if(dX < 0) {
List<UnderlayButton> buffer = new ArrayList<>();
if (!buttonsBuffer.containsKey(pos)){
instantiateUnderlayButton(viewHolder, buffer);
buttonsBuffer.put(pos, buffer);
}
else {
buffer = buttonsBuffer.get(pos);
}
translationX = dX * buffer.size() * BUTTON_WIDTH / itemView.getWidth();
drawButtons(c, itemView, buffer, pos, translationX);
}
}
super.onChildDraw(c, recyclerView, viewHolder, translationX, dY, actionState, isCurrentlyActive);
}
private synchronized void recoverSwipedItem(){
while (!recoverQueue.isEmpty()){
int pos = recoverQueue.poll();
if (pos > -1) {
recyclerView.getAdapter().notifyItemChanged(pos);
}
}
}
private void drawButtons(Canvas c, View itemView, List<UnderlayButton> buffer, int pos, float dX){
float right = itemView.getRight();
float dButtonWidth = (-1) * dX / buffer.size();
for (UnderlayButton button : buffer) {
float left = right - dButtonWidth;
button.onDraw(
c,
new RectF(
left,
itemView.getTop(),
right,
itemView.getBottom()
),
pos
);
right = left;
}
}
public void attachSwipe(){
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(this);
itemTouchHelper.attachToRecyclerView(recyclerView);
}
public abstract void instantiateUnderlayButton(RecyclerView.ViewHolder viewHolder, List<UnderlayButton> underlayButtons);
public static class UnderlayButton {
private String text;
private int imageResId;
private int color;
private int pos;
private RectF clickRegion;
private UnderlayButtonClickListener clickListener;
public UnderlayButton(String text, int imageResId, int color, UnderlayButtonClickListener clickListener) {
this.text = text;
this.imageResId = imageResId;
this.color = color;
this.clickListener = clickListener;
}
public boolean onClick(float x, float y){
if (clickRegion != null && clickRegion.contains(x, y)){
clickListener.onClick(pos);
return true;
}
return false;
}
public void onDraw(Canvas c, RectF rect, int pos){
Paint p = new Paint();
p.setColor(color);
c.drawRect(rect, p);
p.setColor(Color.WHITE);
p.setTextSize(LayoutHelper.getPx(MyApplication.getAppContext(), 12));
Rect r = new Rect();
float cHeight = rect.height();
float cWidth = rect.width();
p.setTextAlign(Paint.Align.LEFT);
p.getTextBounds(text, 0, text.length(), r);
float x = cWidth / 2f - r.width() / 2f - r.left;
float y = cHeight / 2f + r.height() / 2f - r.bottom;
c.drawText(text, rect.left + x, rect.top + y, p);
clickRegion = rect;
this.pos = pos;
}
}
public interface UnderlayButtonClickListener {
void onClick(int pos);
}
}
使用方法：
SwipeHelper swipeHelper = new SwipeHelper(this, recyclerView) {
@Override
public void instantiateUnderlayButton(RecyclerView.ViewHolder viewHolder, List<UnderlayButton> underlayButtons) {
underlayButtons.add(new SwipeHelper.UnderlayButton(
"Delete",
0,
Color.parseColor("#FF3C30"),
new SwipeHelper.UnderlayButtonClickListener() {
@Override
public void onClick(int pos) {
}
}
));
underlayButtons.add(new SwipeHelper.UnderlayButton(
"Transfer",
0,
Color.parseColor("#FF9502"),
new SwipeHelper.UnderlayButtonClickListener() {
@Override
public void onClick(int pos) {
}
}
));
underlayButtons.add(new SwipeHelper.UnderlayButton(
"Unshare",
0,
Color.parseColor("#C7C7CB"),
new SwipeHelper.UnderlayButtonClickListener() {
@Override
public void onClick(int pos) {
}
}
));
}
};
注意: 这个辅助类是为了实现左滑而设计的。你可以在SwipeHelper构造函数中更改滑动方向，并根据onChildDraw方法中的dX进行相应的更改。
如果你想在按钮中显示图片，只需在UnderlayButton中使用imageResId，并重新实现onDraw方法。
已知一个bug，当你从一个条目对角线地滑到另一个时，第一个被触摸的条目会闪烁一下。这可以通过减小getSwipeVelocityThreshold的值来解决，但这会使用户更难以滑动该项。你还可以通过更改getSwipeThreshold和getSwipeEscapeVelocity中的两个其他值来调整滑动的感觉。查看ItemTouchHelper源代码，注释非常有帮助。
我相信有很多优化的空间。这个解决方案仅仅提供了一个想法，如果你想坚持使用ItemTouchHelper，请让我知道是否有问题。以下是屏幕截图。
致谢: 这个解决方案主要受到AdamWei在这篇帖子中的回答的启发。
