如何获得在 RecyclerView 中选择的位置? [英] How do I get the position selected in a RecyclerView?

问题描述

我正在试验支持库的回收视图和卡片.我有卡片的回收者视图.每张卡片的右上角都有一个x"图标，可以将其移除:

I am experimenting with the support library's recyclerview and cards. I have a recyclerview of cards. Each card has an 'x' icon at the top right corner to remove it:

卡片xml，list_item.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="5dp">
<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:id="@+id/taskDesc"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:textSize="40sp"
        android:text="hi"/>
    <ImageView
        android:id="@+id/xImg"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentRight="true"
        android:src="@drawable/ic_remove"/>
</RelativeLayout>
</android.support.v7.widget.CardView>

我试图用我将在 TaskAdapter.java 中的 notifyItemRemoved(position) 中使用的位置标记该行:

I attempted to tag the row with the position I would use in notifyItemRemoved(position) in TaskAdapter.java:

public class TaskAdapter extends RecyclerView.Adapter<TaskAdapter.TaskViewHolder>  {

private List<Task> taskList;
private TaskAdapter thisAdapter = this;


// cache of views to reduce number of findViewById calls
public static class TaskViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    protected TextView taskTV;
    protected ImageView closeBtn;
    public TaskViewHolder(View v) {
        super(v);
        taskTV = (TextView)v.findViewById(R.id.taskDesc);
    }

    @Override
    public void onClick(View v) {
        int position = v.getTag();
        adapter.notifyItemRemoved(position);
    }
}


public TaskAdapter(List<Task> tasks) {
    if(tasks == null)
        throw new IllegalArgumentException("tasks cannot be null");
    taskList = tasks;
}


// onBindViewHolder binds a model to a viewholder
@Override
public void onBindViewHolder(TaskViewHolder taskViewHolder, int pos) {
    final int position = pos;
    Task currTask = taskList.get(pos);
    taskViewHolder.taskTV.setText(currTask.getDescription());

    taskViewHolder.closeBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            thisAdapter.notifyItemRemoved(position);
        }
    });
}

@Override
public int getItemCount() {
    return taskList.size();
}


// inflates row to create a viewHolder
@Override
public TaskViewHolder onCreateViewHolder(ViewGroup parent, int pos) {
    View itemView = LayoutInflater.from(parent.getContext()).
                                   inflate(R.layout.list_item, parent, false);

    return new TaskViewHolder(itemView);
}
}

这不起作用，因为您无法设置标签，我也无法从 onClick 访问适配器.

This won't work because you can't set a tag nor can I access the adapter from onClick.

推荐答案

将 onClickListener 设置在 onBindViewHolder() 上，您就可以从那里访问位置.如果您在 ViewHolder 中设置它们，除非您还将位置传递到 ViewHolder

Set your onClickListeners on onBindViewHolder() and you can access the position from there. If you set them in your ViewHolder you won't know what position was clicked unless you also pass the position into the ViewHolder

编辑

正如 pskink 指出的 ViewHolder 有一个 getPosition() 所以你最初的做法是正确的.

As pskink pointed out ViewHolder has a getPosition() so the way you were originally doing it was correct.

单击视图时，您可以在 ViewHolder 中使用 getPosition() 并返回位置

When the view is clicked you can use getPosition() in your ViewHolder and it returns the position

更新

getPosition() 现已弃用并替换为 getAdapterPosition()

2020 年更新

getAdapterPosition() 现在已弃用并替换为 getAbsoluteAdapterPosition() 或 getBindingAdapterPosition()

getAdapterPosition() is now deprecated and replaced with getAbsoluteAdapterPosition() or getBindingAdapterPosition()

Kotlin 代码:

override fun onBindViewHolder(holder: MyHolder, position: Int) {
        // - get element from your dataset at this position
        val item = myDataset.get(holder.absoluteAdapterPosition)
    }

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