我正在尝试在回收器视图中实施滑动删除操作。我有这段代码。
public abstract class SwipeToDeleteCallback extends ItemTouchHelper.Callback {
private Context context;
private Paint clearPaint;
private ColorDrawable background;
private int backgroundColor;
private Drawable deleteDrawable;
private int intrinsicWidth;
private int intrinsicHeight;
public SwipeToDeleteCallback(Context context) {
this.context = context;
background = new ColorDrawable();
backgroundColor = Color.parseColor("#DB3236");
clearPaint = new Paint();
clearPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
deleteDrawable = ContextCompat.getDrawable(this.context, R.drawable.ic_delete_white_24dp);
intrinsicWidth = deleteDrawable.getIntrinsicWidth();
intrinsicHeight = deleteDrawable.getIntrinsicHeight();
}
@Override
public int getMovementFlags(@NonNull RecyclerView recyclerView,
@NonNull RecyclerView.ViewHolder viewHolder) {
return makeMovementFlags(0, ItemTouchHelper.LEFT);
}
@Override
public boolean onMove(@NonNull RecyclerView recyclerView,
@NonNull RecyclerView.ViewHolder viewHolder,
@NonNull RecyclerView.ViewHolder viewHolder1) {
return false;
}
@Override
public void onChildDraw(@NonNull Canvas canvas, @NonNull RecyclerView recyclerView,
@NonNull RecyclerView.ViewHolder viewHolder, float dX, float dY,
int actionState, boolean isCurrentlyActive) {
super.onChildDraw(canvas, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
View itemView = viewHolder.itemView;
int itemHeight = itemView.getHeight();
boolean isCancelled = dX == 0 && !isCurrentlyActive;
if (isCancelled) {
clearCanvas(canvas, itemView.getRight() + dX, (float) itemView.getTop(),
(float) itemView.getRight(), (float) itemView.getBottom());
super.onChildDraw(canvas, recyclerView, viewHolder, dX, dY, actionState,
isCurrentlyActive);
return;
}
background.setColor(backgroundColor);
background.setBounds(itemView.getRight() + (int) dX, itemView.getTop(),
itemView.getRight(), itemView.getBottom());
background.draw(canvas);
int deleteIconTop = itemView.getTop() + (itemHeight - intrinsicHeight) / 2;
int deleteIconMargin = (itemHeight - intrinsicHeight) / 2;
int deleteIconLeft = itemView.getRight() - deleteIconMargin - intrinsicWidth;
int deleteIconRight = itemView.getRight() - deleteIconMargin;
int deleteIconBottom = deleteIconTop + intrinsicHeight;
deleteDrawable.setBounds(deleteIconLeft, deleteIconTop, deleteIconRight, deleteIconBottom);
deleteDrawable.draw(canvas);
super.onChildDraw(canvas, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
private void clearCanvas(Canvas canvas, Float left, Float top, Float right, Float bottom) {
canvas.drawRect(left, top, right, bottom, clearPaint);
}
@Override
public float getSwipeThreshold(@NonNull RecyclerView.ViewHolder viewHolder) {
return 0.7f;
}
}
但是，问题是该行在刷卡时被删除。我想将其保留在那里，即，当滑动行时，显示删除按钮，然后用户可以单击它，而不是滑动完全删除它，而是在滑动后显示删除按钮。另外，我也在尝试添加“编辑”按钮，但是在左侧带有删除的地方，有什么主意吗？
答案 0 :(得分：0)
创建ItemTouchHelper并将其附加到recyclerview。
将帮助程序附加到RecyclerView的代码
itemTouchHelper = new ItemTouchHelper(simpleCallback);
itemTouchHelper.attachToRecyclerView(recyclerView);
ItemTouchHelper类的代码
ItemTouchHelper.SimpleCallback simpleCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
private void drawText(String text, Canvas c, RectF button, Paint p) {
float textSize = 30;
p.setColor(Color.WHITE);
p.setAntiAlias(true);
p.setTextSize(textSize);
float textWidth = p.measureText(text);
c.drawText(text, button.centerX() - (textWidth / 2), button.centerY() + (textSize / 2), p);
}
@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
View itemView = viewHolder.itemView;
Paint p = new Paint();
if (dX > 0) {
c.drawRect((float) itemView.getLeft(), (float) itemView.getTop(), dX,
(float) itemView.getBottom(), p);
} else {
RectF rightButton = new RectF(itemView.getRight() - 200, (itemView.getTop() + dpToPx(4)),
(itemView.getRight() - dpToPx(4)), (itemView.getBottom() - dpToPx(8)));
p.setColor(ContextCompat.getColor(MainActivity.this, R.color.colorAccent));
c.drawRoundRect(rightButton, 10, 10, p);
drawText("Del", c, rightButton, p);
}
// Fade out the view when it is swiped out of the parent
final float alpha = 1 - Math.abs(dX) / (float) viewHolder.itemView.getWidth();
viewHolder.itemView.setAlpha(alpha);
viewHolder.itemView.setTranslationX(dX);
} else {
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
@Override
public void onSwiped(final RecyclerView.ViewHolder viewHolder, int direction) {
final int position = viewHolder.getAdapterPosition();
if (direction == ItemTouchHelper.LEFT) {
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setMessage("Are you sure to delete?");
builder.setPositiveButton("REMOVE", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
adapter.notifyItemRemoved(position);
mProductViewModel.delete(adapter.getItem(position));
return;
}
}).setNegativeButton("CANCEL", new DialogInterface.OnClickListener() { //not removing items if cancel is done
@Override
public void onClick(DialogInterface dialog, int which) {
adapter.notifyItemRemoved(position + 1);
adapter.notifyItemRangeChanged(position, adapter.getItemCount());
return;
}
}).show(); //show alert dialog
}
}
};
答案 1 :(得分：0)
我发现这种实现轻扫删除的新方法非常友好，那就是在oncreate方法中实现新的ItemTouchHelper（）。您要做的就是在循环窗口中传递要删除的项目的位置。请参阅下面的示例代码。这里我实现了新的ItemTouchHelper（）来删除我在屏幕左右滑动的所有笔记。
代码如下：
new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(0,
ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {
@Override
public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder viewHolder1) {
return false;
}
@Override
public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int i) {
noteViewModel.delete(noteAdapter.getNoteAt(viewHolder.getAdapterPosition()));
Toast.makeText(MainActivity.this, "Note Deleted", Toast.LENGTH_SHORT).show();
}
}).attachToRecyclerView(rv_notes);
rv_notes是我的recyclerview的实例
要了解如何清楚地实现它，请按照我的github中的代码进行操作。以下是链接。 https://github.com/sammymutahigicheru/NoteApp