如何在回收器中切换选择Android中的视图

Question

我有一个应用程序，其中包含一些数据的recyclerView。场景是这样的;当我单击一个项目时，它的图像会发生变化，当我单击另一个项目时，单击项目图像将更改，并且之前单击的项目图像将恢复正常。我已经实现了代码，但我的代码问题是当我单击其他项目时，以前单击的项目图像保持不变。

法典：-

public void toggleSelection(int pos) {
    currentSelectedIndex = pos;
    if (selectedItems.get(pos, false)) {
        selectedItems.delete(pos);
        animationItemsIndex.delete(pos);
    } else {
        selectedItems.put(pos, true);
        animationItemsIndex.put(pos, true);
        animationItemsIndex.delete(pos);
    }
    notifyItemChanged(pos);
}
private SparseBooleanArray selectedItems;
// array used to perform multiple animation at once
private SparseBooleanArray animationItemsIndex;
private boolean reverseAllAnimations = false;

Answer 1

这

进入YourViewHolderClass

@Override
public void onClick(View view) {
    imageView.setSelected(true);
    if (previousSelection != null && imageView != previousSelection)
        previousSelection.setSelected(false);
    previousSelection = imageView;
    if (mClickListener != null)
        mClickListener.onItemClick(view, getAdapterPosition());
}  

此外，您必须在适配器内定义一个接口

 // allows clicks events to be caught
public void setClickListener(ItemClickListener itemClickListener) {
    this.mClickListener = itemClickListener;
}
// parent activity will implement this method to respond to click events
public interface ItemClickListener {
    void onItemClick(View view, int position);
}

基本上，您只需保存所选的上一个视图。

编辑：我在RecyclerView项目上使用了一个selector作为背景

编辑：将此行添加到要在选择时更改的recyclerview item视图中

android:background="@drawable/ic_material_type_selector"

ic_material_type_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_selected="true" 
    android:drawable="<!-- drawable / color for selected state -->"/>
    <item android:state_selected="false" 
    android:drawable="<!-- drawable / color for unselected state -->"/>
</selector>

Answer 2

请尝试这个

currentSelectedIndex = -1;
public void toggleSelection(int pos) {
if(currentSelectedIndex!=-1) {
    //Previous Item is unselected
}
    currentSelectedIndex = pos;
    if (selectedItems.get(pos, false)) {
        // Current item is selected
    } else {
        // Current item is unselected
    }
    notifyItemChanged(pos);
}

Answer 3

公共类 SomeRecyclerAdapter extensions Adapter {

    private int mLastClickedPosition = Integer.MIN_VALUE;

....

    @Override
    public void onBindViewHolder(SomeViewHolder holder, int position) {
        final boolean activatedState = mLastClickedPosition == position;
        holder.itemView.setActivated(activatedState);// this is only example, you can use "activatedState" in different ways
    }
    public void onItemClick(int position) {
        final int lastClickedPosition = mLastClickedPosition;
        mLastClickedPosition = position;
        if (lastClickedPosition >= 0) {
            notifyItemChanged(lastClickedPosition);
        }
        if (mLastClickedPosition >= 0) {
            notifyItemChanged(mLastClickedPosition);
        }
    }
}

从这里： https://gist.github.com/anonymous/4ef280c79c7c3f4aae1406c818149f8c

Answer 4

final int currentClickedPosition = -1;
under button click.....under onBindViewHolder method....
final int lastClickedPosition = currentClickedPosition ;
currentClickedPosition = position;
//do your stuff here............
if(lastClickedPosition != currentClickedPosition ){
    notifyItemChanged(lastClickedPosition);
}

Answer 5

我使用数据类中的布尔值管理当前选择的项目isSelected。

回收商查看物料模型

data class OptionModel(
    var title: String? = "",
    var isSelected: Boolean = false, //control single selected view
    var logo: Int? = 0
)

回收器视图适配器> onBindViewHolder(..,..)

 holder.itemView.setOnClickListener {
   toggleSelection(position)
 }

一般的想法是知道选择了哪个位置，并将其布尔值切换为真，将其他项目的布尔值切换为假。

函数切换选择

 fun toggleSelection(position: Int) {
     var currentSelectIndex = position
     listData.forEachIndexed { index, paymentOption ->
         paymentOption.isSelected = index == currentSelectIndex
     }
     notifyDataSetChanged()
 }

可以在代码中进一步使用相同的值，并且还有助于通过notifyDataSetChanged()来更新 UI