滑动时的 RecyclerView ItemTouchHelper 按钮
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【中文标题】滑动时的 RecyclerView ItemTouchHelper 按钮【英文标题】：RecyclerView ItemTouchHelper Buttons on Swipe 【发布时间】：2017-12-11 10:15:26 【问题描述】：我打算创建一个表格，向左滑动会显示 2 个按钮：编辑和删除。
我一直在玩它，我知道我非常接近。秘诀在于方法 OnChildDraw。
我想绘制一个适合文本删除的矩形，然后使用它们各自的背景颜色在其旁边绘制编辑文本。单击时剩余的空白应将该行恢复到其初始位置。
我已经设法在用户向两侧滑动时绘制背景，但我不知道如何添加侦听器，一旦滑动到一侧，拖动功能就会开始出现异常。
我正在研究 Xamarin，但也接受纯 Java 解决方案，因为我可以轻松地将它们移植到 c#。
public class SavedPlacesItemTouchHelper : ItemTouchHelper.SimpleCallback
private SavedPlacesRecyclerviewAdapter adapter;
private Paint paint = new Paint();
private Context context;
public SavedPlacesItemTouchHelper(Context context, SavedPlacesRecyclerviewAdapter adapter) : base(ItemTouchHelper.ActionStateIdle, ItemTouchHelper.Left)
this.context = context;
this.adapter = adapter;
public override bool OnMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target)
return false;
public override void OnSwiped(RecyclerView.ViewHolder viewHolder, int direction)
public override void OnChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, bool isCurrentlyActive)
float translationX = dX;
View itemView = viewHolder.ItemView;
float height = (float)itemView.Bottom - (float)itemView.Top;
if (actionState == ItemTouchHelper.ActionStateSwipe && dX <= 0) // Swiping Left
translationX = -Math.Min(-dX, height * 2);
paint.Color = Color.Red;
RectF background = new RectF((float)itemView.Right + translationX, (float)itemView.Top, (float)itemView.Right, (float)itemView.Bottom);
c.DrawRect(background, paint);
//viewHolder.ItemView.TranslationX = translationX;
else if (actionState == ItemTouchHelper.ActionStateSwipe && dX > 0) // Swiping Right
translationX = Math.Min(dX, height * 2);
paint.Color = Color.Red;
RectF background = new RectF((float)itemView.Right + translationX, (float)itemView.Top, (float)itemView.Right, (float)itemView.Bottom);
c.DrawRect(background, paint);
base.OnChildDraw(c, recyclerView, viewHolder, translationX, dY, actionState, isCurrentlyActive);
这是我目前拥有的。
如果您知道如何添加听众或有任何建议，请发表评论！
更新：
我刚刚意识到双击该行的白色剩余空间已经将该行恢复到其初始状态。虽然不是一个水龙头:(
【问题讨论】：
遇到同样的问题。 @filthy_wizard 我将很快发布我的解决方案来解决这个问题，因为我所做的与接受的答案略有不同 【参考方案1】：我遇到了同样的问题，并试图在网上找到解决方案。大多数解决方案使用两层方法（一层视图项，另一层按钮），但我只想坚持使用 ItemTouchHelper。最后，我想出了一个可行的解决方案。请在下方查看。
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();
// Draw background
p.setColor(color);
c.drawRect(rect, p);
// Draw Text
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);
用法：
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)
// TODO: onDelete
));
underlayButtons.add(new SwipeHelper.UnderlayButton(
"Transfer",
0,
Color.parseColor("#FF9502"),
new SwipeHelper.UnderlayButtonClickListener()
@Override
public void onClick(int pos)
// TODO: OnTransfer
));
underlayButtons.add(new SwipeHelper.UnderlayButton(
"Unshare",
0,
Color.parseColor("#C7C7CB"),
new SwipeHelper.UnderlayButtonClickListener()
@Override
public void onClick(int pos)
// TODO: OnUnshare
));
;
注意：这个帮助类是为左滑设计的。您可以在 SwipeHelper 的 构造函数中更改滑动方向，并在 onChildDraw 方法中根据 dX 进行相应更改。
如果要在按钮中显示图片，只需在UnderlayButton中使用imageResId，并重新实现onDraw方法即可.
有一个已知的错误，当你从一个项目对角滑动一个项目到另一个项目时，第一个触摸的项目会闪烁一点。这可以通过减小 getSwipeVelocityThreshold 的值来解决，但这会使用户更难滑动项目。您还可以通过更改 getSwipeThreshold 和 getSwipeEscapeVelocity 中的另外两个值来调整滑动感觉。查看 ItemTouchHelper 源代码，cmets 很有帮助。
我相信有很多地方可以优化。如果您想坚持使用 ItemTouchHelper，此解决方案只是给出了一个想法。如果您在使用它时遇到问题，请告诉我。下面是截图。
致谢：这个解决方案的灵感主要来自 AdamWei 在post
中的回答【讨论】：
我不得不放弃这个解决方案。最终在左侧滑动时进行删除并在右侧滑动时进行编辑。但我想使用按钮。您的解决方案似乎合法，我将在下周尝试，如果有问题我会告诉您，如果有效，我会将其标记为已接受的答案：D @coderindigo 抱歉。我仍然无法重现它。但我可以看到如果 swipedPos 没有正确重置，就会发生这种情况。你的想法是可行的。在 onTouch 方法的 if (rect.top point.y) 语句中添加一个额外的条件可以修复它。我会添加（&& point.x 在底层按钮的总点击区域中）。 @WenxiZeng我谢谢！通过维护一个变量 swipedBack 并在 dx==0 时将其设置为 onChildDraw 来解决我遇到的问题。另外，我需要问的另一件事是我可以同时左右滑动吗？我想我需要一个新的左键缓冲区？ @GeorgiyChebotarev 抱歉，我没有它的存储库。对于使用，在您的活动或片段中或任何您有回收站视图实例的地方，复制/粘贴使用并传递上下文和回收站视图。那么你应该很高兴 您可能希望在UnderlayButton 的onDraw() 中使用Paint.setAntiAlias(true) 和Paint.setSubpixelText(true) 以使按钮文本更平滑（不像素化）【参考方案2】：
这是基于公认答案方法的 Kotlin 版本。通过一些小的更改，我设法根据文本的固有大小而不是使用固定宽度来呈现按钮宽度。
演示项目：https://github.com/ntnhon/RecyclerViewRowOptionsDemo
SwipeHelper的实现：
import android.annotation.SuppressLint
import android.content.Context
import android.graphics.*
import android.view.MotionEvent
import android.view.View
import androidx.annotation.ColorRes
import androidx.core.content.ContextCompat
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.RecyclerView
import java.util.*
import kotlin.math.abs
import kotlin.math.max
abstract class SwipeHelper(
private val recyclerView: RecyclerView
) : ItemTouchHelper.SimpleCallback(
ItemTouchHelper.ACTION_STATE_IDLE,
ItemTouchHelper.LEFT
)
private var swipedPosition = -1
private val buttonsBuffer: MutableMap<Int, List<UnderlayButton>> = mutableMapOf()
private val recoverQueue = object : LinkedList<Int>()
override fun add(element: Int): Boolean
if (contains(element)) return false
return super.add(element)
@SuppressLint("ClickableViewAccessibility")
private val touchListener = View.OnTouchListener _, event ->
if (swipedPosition < 0) return@OnTouchListener false
buttonsBuffer[swipedPosition]?.forEach it.handle(event)
recoverQueue.add(swipedPosition)
swipedPosition = -1
recoverSwipedItem()
true
init
recyclerView.setOnTouchListener(touchListener)
private fun recoverSwipedItem()
while (!recoverQueue.isEmpty())
val position = recoverQueue.poll() ?: return
recyclerView.adapter?.notifyItemChanged(position)
private fun drawButtons(
canvas: Canvas,
buttons: List<UnderlayButton>,
itemView: View,
dX: Float
)
var right = itemView.right
buttons.forEach button ->
val width = button.intrinsicWidth / buttons.intrinsicWidth() * abs(dX)
val left = right - width
button.draw(
canvas,
RectF(left, itemView.top.toFloat(), right.toFloat(), itemView.bottom.toFloat())
)
right = left.toInt()
override fun onChildDraw(
c: Canvas,
recyclerView: RecyclerView,
viewHolder: RecyclerView.ViewHolder,
dX: Float,
dY: Float,
actionState: Int,
isCurrentlyActive: Boolean
)
val position = viewHolder.adapterPosition
var maxDX = dX
val itemView = viewHolder.itemView
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE)
if (dX < 0)
if (!buttonsBuffer.containsKey(position))
buttonsBuffer[position] = instantiateUnderlayButton(position)
val buttons = buttonsBuffer[position] ?: return
if (buttons.isEmpty()) return
maxDX = max(-buttons.intrinsicWidth(), dX)
drawButtons(c, buttons, itemView, maxDX)
super.onChildDraw(
c,
recyclerView,
viewHolder,
maxDX,
dY,
actionState,
isCurrentlyActive
)
override fun onMove(
recyclerView: RecyclerView,
viewHolder: RecyclerView.ViewHolder,
target: RecyclerView.ViewHolder
): Boolean
return false
override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int)
val position = viewHolder.adapterPosition
if (swipedPosition != position) recoverQueue.add(swipedPosition)
swipedPosition = position
recoverSwipedItem()
abstract fun instantiateUnderlayButton(position: Int): List<UnderlayButton>
//region UnderlayButton
interface UnderlayButtonClickListener
fun onClick()
class UnderlayButton(
private val context: Context,
private val title: String,
textSize: Float,
@ColorRes private val colorRes: Int,
private val clickListener: UnderlayButtonClickListener
)
private var clickableRegion: RectF? = null
private val textSizeInPixel: Float = textSize * context.resources.displayMetrics.density // dp to px
private val horizontalPadding = 50.0f
val intrinsicWidth: Float
init
val paint = Paint()
paint.textSize = textSizeInPixel
paint.typeface = Typeface.DEFAULT_BOLD
paint.textAlign = Paint.Align.LEFT
val titleBounds = Rect()
paint.getTextBounds(title, 0, title.length, titleBounds)
intrinsicWidth = titleBounds.width() + 2 * horizontalPadding
fun draw(canvas: Canvas, rect: RectF)
val paint = Paint()
// Draw background
paint.color = ContextCompat.getColor(context, colorRes)
canvas.drawRect(rect, paint)
// Draw title
paint.color = ContextCompat.getColor(context, android.R.color.white)
paint.textSize = textSizeInPixel
paint.typeface = Typeface.DEFAULT_BOLD
paint.textAlign = Paint.Align.LEFT
val titleBounds = Rect()
paint.getTextBounds(title, 0, title.length, titleBounds)
val y = rect.height() / 2 + titleBounds.height() / 2 - titleBounds.bottom
canvas.drawText(title, rect.left + horizontalPadding, rect.top + y, paint)
clickableRegion = rect
fun handle(event: MotionEvent)
clickableRegion?.let
if (it.contains(event.x, event.y))
clickListener.onClick()
//endregion
private fun List<SwipeHelper.UnderlayButton>.intrinsicWidth(): Float
if (isEmpty()) return 0.0f
return map it.intrinsicWidth .reduce acc, fl -> acc + fl
用法：
private fun setUpRecyclerView()
binding.recyclerView.adapter = Adapter(listOf(
"Item 0: No action",
"Item 1: Delete",
"Item 2: Delete & Mark as unread",
"Item 3: Delete, Mark as unread & Archive"
))
binding.recyclerView.addItemDecoration(DividerItemDecoration(this, DividerItemDecoration.VERTICAL))
binding.recyclerView.layoutManager = LinearLayoutManager(this)
val itemTouchHelper = ItemTouchHelper(object : SwipeHelper(binding.recyclerView)
override fun instantiateUnderlayButton(position: Int): List<UnderlayButton>
var buttons = listOf<UnderlayButton>()
val deleteButton = deleteButton(position)
val markAsUnreadButton = markAsUnreadButton(position)
val archiveButton = archiveButton(position)
when (position)
1 -> buttons = listOf(deleteButton)
2 -> buttons = listOf(deleteButton, markAsUnreadButton)
3 -> buttons = listOf(deleteButton, markAsUnreadButton, archiveButton)
else -> Unit
return buttons
)
itemTouchHelper.attachToRecyclerView(binding.recyclerView)
private fun toast(text: String)
toast?.cancel()
toast = Toast.makeText(this, text, Toast.LENGTH_SHORT)
toast?.show()
private fun deleteButton(position: Int) : SwipeHelper.UnderlayButton
return SwipeHelper.UnderlayButton(
this,
"Delete",
14.0f,
android.R.color.holo_red_light,
object : SwipeHelper.UnderlayButtonClickListener
override fun onClick()
toast("Deleted item $position")
)
private fun markAsUnreadButton(position: Int) : SwipeHelper.UnderlayButton
return SwipeHelper.UnderlayButton(
this,
"Mark as unread",
14.0f,
android.R.color.holo_green_light,
object : SwipeHelper.UnderlayButtonClickListener
override fun onClick()
toast("Marked as unread item $position")
)
private fun archiveButton(position: Int) : SwipeHelper.UnderlayButton
return SwipeHelper.UnderlayButton(
this,
"Archive",
14.0f,
android.R.color.holo_blue_light,
object : SwipeHelper.UnderlayButtonClickListener
override fun onClick()
toast("Archived item $position")
)
【讨论】：
真正有趣的方法！您认为这种方法是否适合在每个 underlat 按钮的文本顶部放置一个可绘制对象？ @MateoHervas 是的，您可以通过调整 UnderlayButton 绘制功能。它涉及更多的绘制逻辑。我正忙于一些项目，所以现在我不能玩它。 2020年解决这个问题的最佳方法！ 我下载了示例项目并将所有库更新到最新版本。不知何故，拖动无法正常工作。 notifydataset 更改或再次设置适配器后无法正常工作【参考方案3】：对于所有想要为此使用库的人，请查看：
https://github.com/chthai64/SwipeRevealLayout
并且，对于这个库的精简版本，结帐：
https://android.jlelse.eu/android-recyclerview-swipeable-items-46a3c763498d
附：您可以使用这些创建任何自定义布局（即使使用Image Buttons）作为隐藏布局。
【讨论】：
【参考方案4】：为了能够绘制可绘制对象而不是文本，我做了以下操作：
在SwipeHelper，我改了
UnderlayButton(String text, int imageResId, int color, UnderlayButtonClickListener clickListener)
到
UnderlayButton(String text, Bitmap bitmap, int color, UnderlayButtonClickListener clickListener)
当然，我删除了imageResId，而是创建了一个Bitmap bitmap，并使用this.bitmap = bitmap;作为其余变量将构造函数变量传递给它。
在SwipeHelper.onDaw() 中，您可以调用drawBitmap() 将您的位图应用到画布上。例如：
c.drawBitmap(bitmap, rect.left, rect.top, p);
c 和 p 以及您的 Canvas 和 Paint 变量分别在哪里。
在我调用UnderlayButton 的活动中，我使用this method 将我的drawable（在我的情况下是VectorDrawable）转换为位图：
int idDrawable = R.drawable.ic_delete_white;
Bitmap bitmap = getBitmapFromVectorDrawable(getContext(), idDrawable);
剩下要做的是图标的居中。
文本和位图均居中的完整 onDraw 方法：
public void onDraw(Canvas c, RectF rect, int pos)
Paint p = new Paint();
// Draw background
p.setColor(color);
c.drawRect(rect, p);
// Draw Text
p.setColor(Color.WHITE);
p.setTextSize(24);
float spaceHeight = 10; // change to whatever you deem looks better
float textWidth = p.measureText(text);
Rect bounds = new Rect();
p.getTextBounds(text, 0, text.length(), bounds);
float combinedHeight = bitmap.getHeight() + spaceHeight + bounds.height();
c.drawBitmap(bitmap, rect.centerX() - (bitmap.getWidth() / 2), rect.centerY() - (combinedHeight / 2), null);
//If you want text as well with bitmap
c.drawText(text, rect.centerX() - (textWidth / 2), rect.centerY() + (combinedHeight / 2), p);
clickRegion = rect;
this.pos = pos;
【讨论】：
@TobySpeight 让图标居中试试这个 c.drawBitmap(bitmap, rect.left+x/2 - 1, rect.top+y/2 - 4, p);【参考方案5】：按照曾文曦的回答here，如果你想让按钮中的文本多行，请将UnderlayButton的onDraw方法替换为：
public void onDraw(Canvas canvas, RectF rect, int pos)
Paint p = new Paint();
// Draw background
p.setColor(color);
canvas.drawRect(rect, p);
// Draw Text
TextPaint textPaint = new TextPaint();
textPaint.setTextSize(UtilitiesOperations.convertDpToPx(getContext(), 15));
textPaint.setColor(Color.WHITE);
StaticLayout sl = new StaticLayout(text, textPaint, (int)rect.width(),
Layout.Alignment.ALIGN_CENTER, 1, 1, false);
canvas.save();
Rect r = new Rect();
float y = (rect.height() / 2f) + (r.height() / 2f) - r.bottom - (sl.getHeight() /2);
canvas.translate(rect.left, rect.top + y);
sl.draw(canvas);
canvas.restore();
clickRegion = rect;
this.pos = pos;
【讨论】：
【参考方案6】：如果您想在向另一个方向滑动时在左侧也有按钮，只需尝试在existing answer 中添加这些简单的行：
在drawButtons 方法中：
private void drawButtons(Canvas c, View itemView, List<UnderlayButton> buffer, int pos, float dX)
float right = itemView.getRight();
float left = itemView.getLeft();
float dButtonWidth = (-1) * dX / buffer.size();
for (UnderlayButton button : buffer)
if (dX < 0)
left = right - dButtonWidth;
button.onDraw(
c,
new RectF(
left,
itemView.getTop(),
right,
itemView.getBottom()
),
pos, dX //(to draw button on right)
);
right = left;
else if (dX > 0)
right = left - dButtonWidth;
button.onDraw(c,
new RectF(
right,
itemView.getTop(),
left,
itemView.getBottom()
), pos, dX //(to draw button on left)
);
在onDraw 方法中检查dX 的值并设置按钮的文本和颜色：
public void onDraw(Canvas c, RectF rect, int pos, float dX)
Paint p = new Paint();
// Draw background
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
if (dX > 0)
p.setColor(Color.parseColor("#23d2c5"));
else if (dX < 0)
p.setColor(Color.parseColor("#23d2c5"));
c.drawRect(rect, p);
// Draw Text
p.setColor(Color.WHITE);
p.setTextSize(36);
// 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;
if (dX > 0)
p.setColor(Color.parseColor("#23d2c5"));
c.drawText("Reject", rect.left + x, rect.top + y, p);
else if (dX < 0)
c.drawText(text, rect.left + x, rect.top + y, p);
clickRegion = rect;
this.pos = pos;
【讨论】：
嘿，你能分享整个代码吗，实际上我也在 swipeHelper 类中做了一些更改，我可以在两侧显示滑动项目，但只能在左侧或右侧单击工作 整个代码不会出现在评论框中，我的编辑将被审查。我不知道如何将 SO 上的完整代码发送给您。 好的，恭喜。我在这里制作了多个片段来评论我的代码。 能够将视图移到左侧，但点击事件不起作用...有什么解决方法吗？ 无法在另一侧添加滑动。如何实现左右滑动？？？【参考方案7】：我迟到了，但如果有人在寻找 UIKit UITableView 删除按钮行为，那么您可以在 Xamarin.Android 中将类似的东西与 RecyclerView 一起使用：
public class SwipeDeleteHelper : ItemTouchHelper.Callback
private int _startingWidth = 0;
private bool? _rightAlignedText = null;
private bool _alreadyClicked = false;
private static float _previousDx = float.NegativeInfinity;
private static float _viewWidth = float.NegativeInfinity;
private static float _permanentlyDeleteThreshold = float.NegativeInfinity;
private static RecyclerView.ViewHolder _currentViewHolder;
private RecyclerView.ViewHolder CurrentViewHolder
get => _currentViewHolder;
set
_startingWidth = 0;
_rightAlignedText = null;
_alreadyClicked = false;
_previousDx = float.NegativeInfinity;
_currentViewHolder = value;
/*
You can create a method in a utility class for the buttonwidth conversion like this:
public static float GetPxFromDp(float dp)
return dp * Application.Context.ApplicationContext.Resources.DisplayMetrics.Density;
Also you can use text width measurement to determine the optimal width of the button for your delete text.
*/
public static int buttonWidth = 60 * Application.Context.ApplicationContext.Resources.DisplayMetrics.Density;
public override int GetMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder)
if (viewHolder is EntryCell)
return MakeMovementFlags(ItemTouchHelper.ActionStateIdle, ItemTouchHelper.Left | ItemTouchHelper.Start | ItemTouchHelper.Right | ItemTouchHelper.End);
return MakeMovementFlags(ItemTouchHelper.ActionStateIdle, ItemTouchHelper.ActionStateIdle);
public override void OnSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState)
if (float.IsNegativeInfinity(_permanentlyDeleteThreshold))
_viewWidth = viewHolder.ItemView.Width;
_permanentlyDeleteThreshold = (viewHolder.ItemView.Width * 3f / 4f);
if (viewHolder != CurrentViewHolder)
if (viewHolder != null) // This is a new selection and the button of the previous viewHolder should get hidden.
(CurrentViewHolder as EntryCell)?.ResetView(CurrentViewHolder);
CurrentViewHolder = viewHolder;
else if (CurrentViewHolder != null) // This is the end of the previous selection
var hidden = CurrentViewHolder.ItemView.FindViewById<Button>(Resource.Id.fileListDeleteButton);
_previousDx = float.NegativeInfinity;
if (hidden.LayoutParameters.Width > _permanentlyDeleteThreshold && !_alreadyClicked) // released in permanent delete area
_alreadyClicked = true;
hidden.LayoutParameters.Width = CurrentViewHolder.ItemView.Width;
hidden.CallOnClick();
CurrentViewHolder = null;
else
_startingWidth = hidden.LayoutParameters.Width >= buttonWidth ? buttonWidth : 0;
hidden.LayoutParameters.Width = _startingWidth;
AlignDeleteButtonText(hidden);
hidden.RequestLayout();
base.OnSelectedChanged(viewHolder, actionState);
public override void OnChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, bool isCurrentlyActive)
if (actionState == ItemTouchHelper.ActionStateSwipe && !_alreadyClicked)
var hidden = viewHolder.ItemView.FindViewById<Button>(Resource.Id.fileListDeleteButton);
if (isCurrentlyActive) // swiping
if (float.IsNegativeInfinity(_previousDx)) // This is a new swipe
_previousDx = dX;
if (Math.Abs(dX - _previousDx) > 0.1f && Math.Abs(dX - (-_viewWidth)) > 0.1f)
hidden.LayoutParameters.Width = Math.Max(0, (int)Math.Round(hidden.LayoutParameters.Width - (dX >= _previousDx ? 1 : -1) * (Math.Abs(dX - _previousDx))));
_previousDx = dX;
AlignDeleteButtonText(hidden);
hidden.RequestLayout();
private void AlignDeleteButtonText(Button hidden)
if (_rightAlignedText != false && hidden.LayoutParameters.Width >= _permanentlyDeleteThreshold) // pulled into permanent delete area
hidden.Gravity = GravityFlags.AxisSpecified | GravityFlags.AxisPullBefore | GravityFlags.CenterVertical;
_rightAlignedText = false;
else if (_rightAlignedText != null && hidden.LayoutParameters.Width <= buttonWidth)
hidden.Gravity = GravityFlags.Center;
_rightAlignedText = null;
else if (_rightAlignedText != true && hidden.LayoutParameters.Width > buttonWidth && hidden.LayoutParameters.Width < _permanentlyDeleteThreshold) // pulled back from permanent delete area
hidden.Gravity = GravityFlags.AxisSpecified | GravityFlags.AxisPullAfter | GravityFlags.CenterVertical;
_rightAlignedText = true;
public override bool OnMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) return false;
public override void OnSwiped(RecyclerView.ViewHolder viewHolder, int direction)
EntryCell 是 MvxRecyclerViewHolder 的后代，它应该包含如下内容：
public class EntryCell : MvxRecyclerViewHolder
public EntryCell(View itemView, IMvxAndroidBindingContext context) : base(itemView, context)
Button _delButton = itemView.FindViewById<Button>(Resource.Id.fileListDeleteButton);
_delButton.Text = "Delete";
public void ResetView(RecyclerView.ViewHolder currentViewHolder)
var hidden = currentViewHolder.ItemView.FindViewById<Button>(Resource.Id.fileListDeleteButton);
hidden.LayoutParameters.Width = 0;
hidden.RequestLayout();
您的视图中应该有一个按钮（在 EntryCell 中作为 Resource.Id.fileListDeleteButton 引用，因此该按钮的 ID 是 fileListDeleteButton）。我使用 XML 作为视图，它看起来像这样：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_
android:layout_
android:orientation="vertical">
<!-- The rest of your code... -->
<Button
android:id="@+id/fileListDeleteButton"
android:layout_
android:layout_
android:layout_alignParentRight="true"
android:paddingHorizontal="@dimen/abc_button_padding_horizontal_material"
android:background="#f00"
android:textColor="@android:color/white"
android:textAllCaps="false"
android:singleLine="true"
android:ellipsize="none"
android:text="dummy" />
</RelativeLayout>
在 RecyclerView 所在的代码中，像这样使用它：
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(new SwipeDeleteHelper());
itemTouchHelper.AttachToRecyclerView(yourRecyclerView);
我希望这对某人有所帮助。
【讨论】：
【参考方案8】：由于我在任何地方都没有看到如何实现这一点，并且我确实设法让它工作，我将发布一个解决这个问题的解决方案，但它在 c# Xamarin Android 中是有效的。
如果你需要它原生的 android，你必须将它转换成原生的 android，这应该不难。如果非常需要，我可能会在以后这样做。
这是我的 ItemHelper 基类：
internal abstract class ItemTouchHelperBase : ItemTouchHelper.Callback
protected RecyclerViewAdapterBase adapter;
public int currentPosition = -1;
public Rect ItemRect = new Rect();
private Paint backgroundPaint = new Paint();
private Rect backgroundBounds = new Rect();
private TextPaint textPaint = new TextPaint();
private string deleteText;
private readonly float textWidth;
private readonly float textHeight;
public ItemTouchHelperBase()
backgroundPaint.Color = new Color(ContextCompat.GetColor(Application.Context, Resource.Color.delete_red));
textPaint.Color = Color.White;
textPaint.AntiAlias = true;
textPaint.TextSize = FontHelper.GetFontSize(Application.Context, Resource.Dimension.font_size_button);
deleteText = " " + StringResource.delete + " ";
Rect textBounds = new Rect();
textPaint.GetTextBounds(deleteText, 0, deleteText.Length, textBounds);
textHeight = textBounds.Height();
textWidth = textPaint.MeasureText(deleteText);
public override bool OnMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target)
return false;
public override void ClearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder)
if (adapter != null)
ItemRect = new Rect();
base.ClearView(recyclerView, viewHolder);
public override void OnSwiped(RecyclerView.ViewHolder viewHolder, int direction)
public override void OnChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, bool isCurrentlyActive)
// Note: Don't create variables inside OnDraw due to performance issues
try
if (actionState == ItemTouchHelper.ActionStateSwipe)
if (dX <= 0) // Left swipe
// Swipe up to text width accordingly to ratio
dX /= viewHolder.ItemView.Right / textWidth;
//Draw background
backgroundBounds = new Rect(
viewHolder.ItemView.Right + (int) dX,
viewHolder.ItemView.Top,
viewHolder.ItemView.Right,
viewHolder.ItemView.Bottom);
c.DrawRect(backgroundBounds, backgroundPaint);
if (adapter != null)
ItemRect = backgroundBounds;
//Draw text
c.DrawText(
deleteText,
(float) viewHolder.ItemView.Right - textWidth, viewHolder.ItemView.Top + (viewHolder.ItemView.Height / 2) + (textHeight / 2),
textPaint);
base.OnChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
catch (Exception)
internal void AttachToRecyclerview(RecyclerView recycleview)
new ItemTouchHelper(this).AttachToRecyclerView(recycleview);
public void ClickOutsideDeleteButton()
try
if (currentPosition != -1)
PutRowBackToDefault();
catch (Exception)
protected void PutRowBackToDefault()
adapter.NotifyItemChanged(currentPosition);
currentPosition = -1;
然后在你的项目助手类上你有：
internal class MyItemsTouchHelperCallback : ItemTouchHelperBase
public MyItemsTouchHelperCallback (MyAdapter adapter)
this.adapter = adapter;
public override int GetMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder)
try
if (currentPosition != -1 && currentPosition != viewHolder.AdapterPosition)
PutRowBackToDefault();
currentPosition = viewHolder.AdapterPosition;
catch (Exception)
int swipeFlags = viewHolder is MyViewHolder ? ItemTouchHelper.Start : ItemTouchHelper.ActionStateIdle;
return MakeMovementFlags(ItemTouchHelper.ActionStateIdle, swipeFlags);
那么在你的活动中你有：
把这个 OnCreate
recycleViewLayoutManager = new LinearLayoutManager(this);
recycler_view_main.SetLayoutManager(recycleViewLayoutManager);
recyclerAdapter = new MyAdapter(this, this);
recycler_view_main.SetAdapter(recyclerAdapter);
myItemsTouchHelperCallback = new MyItemsTouchHelperCallback (recyclerAdapter);
myItemsTouchHelperCallback .AttachToRecyclerview(recycler_view_main);
然后在活动中覆盖此方法：
public override bool DispatchTouchEvent(MotionEvent e)
int[] recyclerviewLocationOnScreen = new int[2];
recycler_view_main.GetLocationOnScreen(recyclerviewLocationOnScreen);
TouchEventsHelper.TouchUpEvent(
e.Action,
e.GetX() - recyclerviewLocationOnScreen[0],
e.GetY() - recyclerviewLocationOnScreen[1],
myItemsTouchHelperCallback .ItemRect,
delegate
// Delete your row
,
delegate
myItemsTouchHelperCallback .ClickOutsideDeleteButton(); );
return base.DispatchTouchEvent(e);
这是我创建的用于调度事件的辅助方法：
internal static void TouchUpEvent(MotionEventActions eventActions, float x, float y, Rect rectangle, Action ActionDeleteClick, Action NormalClick)
try
if (rectangle.Contains((int) x, (int) y))
//inside delete button
if (eventActions == MotionEventActions.Down)
isClick = true;
else if (eventActions == MotionEventActions.Up || eventActions == MotionEventActions.Cancel)
if (isClick)
ActionDeleteClick.Invoke();
else if (eventActions == MotionEventActions.Up ||
eventActions == MotionEventActions.Cancel ||
eventActions == MotionEventActions.Down)
//click anywhere outside delete button
isClick = false;
if (eventActions == MotionEventActions.Down)
NormalClick.Invoke();
catch (Exception)
它有点复杂，但效果很好。我已经在很多方面对此进行了测试。如果您在执行此操作时遇到任何问题，请告诉我
【讨论】：
【参考方案9】：如果您使用RecyclerView，请尝试使用OnScrollListener。做这样的事情。
private class YourOnScrollListener extends RecyclerView.OnScrollListener
private boolean directionLeft;
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState)
if (newState == RecyclerView.SCROLL_STATE_IDLE)
if (directionLeft) drawButtons();
//Draw buttons here if you want them to be drawn after scroll is finished
//here you can play with states, to draw buttons or erase it whenever you want
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy)
super.onScrolled(recyclerView, dx, dy);
if (dx < 0) directionLeft = true;
else directionLeft = false;
【讨论】：
如果我的项目触摸助手失败了，我一定会试一试，谢谢！【参考方案10】：我也想在我的应用程序中使用这种触摸手势，在使用了 Itemtouchhelper 之后，我决定编写自己的触摸处理程序：
private class TouchHelper : Java.Lang.Object, View.IOnTouchListener
ViewHolder vh;
public TouchHelper(ViewHolder vh)
this.vh = vh;
float DownX, DownY; bool isSliding;
TimeSpan tsDown;
public bool OnTouch(View v, MotionEvent e)
switch (e.Action)
case MotionEventActions.Down:
DownX = e.GetX(); DownY = e.GetY();
tsDown = TimeSpan.Now;
break;
case MotionEventActions.Move:
float deltaX = e.GetX() - DownX, deltaY = e.GetX() - DownY;
if (Math.Abs(deltaX) >= Values.ScreenWidth / 20 || Math.Abs(deltaY) >= Values.ScreenWidth / 20)
isSliding = Math.Abs(deltaX) > Math.Abs(deltaY);
//TextsPlace is the layout that moves with touch
if(isSliding)
vh.TextsPlace.TranslationX = deltaX / 2;
break;
case MotionEventActions.Cancel:
case MotionEventActions.Up:
//handle if touch was for clicking
if (Math.Abs(deltaX) <= 50 && (TimeSpan.Now - tsDown).TotalMilliseconds <= 400)
vh.OnTextsPlaceClick(vh.TextsPlace, null);
break;
return true;
注意：当创建视图时，将其设置为视图内容的 ontouchlistener。您可以添加动画以将项目返回到它的第一个位置。
您还可以编写自定义布局管理器以在项目滑动时阻止垂直滚动。
【讨论】：
我还在玩 ItemTouchHelper，一旦我用尽了所有可能的结果，我就可以尝试你的技术。感谢分享。【参考方案11】：我有一个更简单的解决方案：
-
向您的 XML 行添加一个按钮，宽度为 0，浮动在右侧：
> <Button > android:id="@+id/hidden" > android:layout_ > android:layout_ > android:layout_alignParentRight = "true">
在 onChildDraw() 中，只需将其宽度增加 dX 值即可。
int position = viewHolder.getAdapterPosition();
View v = recyclerView.getLayoutManager().findViewByPosition(position);
Button hidden = v.findViewById(R.id.hidden);
hidden.setLayoutParams(new LinearLayout.LayoutParams((int)-dX, -1));
确保不要调用默认的 super.onChildDraw()
【讨论】：
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