Question

我有一个Recyclerview，允许在编辑模式下拖放项目。一旦用户退出编辑模式，我需要禁用拖放功能。

我已尝试更改ItemTouchCallback中的内容，包括移动标志和isLongPressDragEnabled无效。长按继续开始拖动事件。

我目前的解决方案是分离并重新连接片段，然后再次进入编辑模式时添加回调，但我希望有一些更清洁的东西，我不知道。

回调：

library(data.table)

# Crate a df for this demo.
mydf <- iris

# Choose columns that you want to apply lag() and create new colnames.
cols = names(iris)[sapply(iris, is.numeric)]
anscols = paste("lag_", cols, sep = "")

# Apply shift() to each of the chosen columns.
setDT(mydf)[, (anscols) := shift(.SD, 1, type = "lag"),
            .SDcols = cols]

     Sepal.Length Sepal.Width Petal.Length Petal.Width   Species lag_Sepal.Length lag_Sepal.Width
 1:          5.1         3.5          1.4         0.2    setosa               NA              NA
 2:          4.9         3.0          1.4         0.2    setosa              5.1             3.5
 3:          4.7         3.2          1.3         0.2    setosa              4.9             3.0
 4:          4.6         3.1          1.5         0.2    setosa              4.7             3.2
 5:          5.0         3.6          1.4         0.2    setosa              4.6             3.1
 ---                                                                                             
146:          6.7         3.0          5.2         2.3 virginica              6.7             3.3
147:          6.3         2.5          5.0         1.9 virginica              6.7             3.0
148:          6.5         3.0          5.2         2.0 virginica              6.3             2.5
149:          6.2         3.4          5.4         2.3 virginica              6.5             3.0
150:          5.9         3.0          5.1         1.8 virginica              6.2             3.4
     lag_Petal.Length lag_Petal.Width
  1:               NA              NA
  2:              1.4             0.2
  3:              1.4             0.2
  4:              1.3             0.2
  5:              1.5             0.2
 ---                                 
146:              5.7             2.5
147:              5.2             2.3
148:              5.0             1.9
149:              5.2             2.0
150:              5.4             2.3

适配器：

public class ItemTouchCallback extends ItemTouchHelper.Callback {


private final ItemTouchHelperAdapter mAdapter;

public ItemTouchCallback(ItemTouchHelperAdapter mAdapter) {
    this.mAdapter = mAdapter;
}

@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    int dragFlags = ItemTouchHelper.START | ItemTouchHelper.END |ItemTouchHelper.DOWN | ItemTouchHelper.UP;
    return makeMovementFlags(dragFlags, 0);
}

@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
    mAdapter.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());
    return true;
}

@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {

}

@Override
public boolean isLongPressDragEnabled() {
    return true;
}


@Override
public boolean isItemViewSwipeEnabled() {
    return false;
}

@Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
    if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
        if (viewHolder instanceof ItemTouchHelperViewHolder) {
            ItemTouchHelperViewHolder itemViewHolder = (ItemTouchHelperViewHolder) viewHolder;
            itemViewHolder.onItemSelected();
        }
    }
    super.onSelectedChanged(viewHolder, actionState);
}

@Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    if (viewHolder instanceof ItemTouchHelperViewHolder) {
        ItemTouchHelperViewHolder itemViewHolder = (ItemTouchHelperViewHolder) viewHolder;
        itemViewHolder.onItemClear();
    }
}
}

片段：

public interface ItemTouchHelperAdapter {

void onItemMove(int fromPosition, int toPosition);
void onItemDismiss(int position);
}

感谢。

Answer 1

在你的ItemTouchCallback

中

boolean mDraggable = false;

@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    int dragFlags = mDraggable ? UP | DOWN | START | END : 0;
    return makeMovementFlags(dragFlags, 0);
}
public void setDraggable(boolean value) {
    mDraggable = value;
}

Answer 2

这就是我这样做的方式：

if(mode == MODE_CREATE){
  touchHelper.attachToRecyclerView(recyclerView);
}else if(mode == MODE_EDIT){
  touchHelper.attachToRecyclerView(null);
}

如何在recyclerview上启用和禁用拖放

2 个答案: