我正在探索RecyclerView,我很惊讶地看到,RecyclerView没有onItemClickListener()。

我有两个问题。

主要问题

我想知道为什么谷歌删除onItemClickListener()?

是否存在性能问题或其他问题?

次要的问题

我解决了我的问题写onClick在我的RecyclerView。适配器:

public static class ViewHolder extends RecyclerView.ViewHolder implements OnClickListener {

    public TextView txtViewTitle;
    public ImageView imgViewIcon;

    public ViewHolder(View itemLayoutView) {
        super(itemLayoutView);
        txtViewTitle = (TextView) itemLayoutView.findViewById(R.id.item_title);
        imgViewIcon = (ImageView) itemLayoutView.findViewById(R.id.item_icon);
    }

    @Override
    public void onClick(View v) {

    }
}

这样可以吗/有更好的办法吗?


当前回答

RecyclerView没有一个onItemClickListener,因为RecyclerView负责回收视图(惊讶!),所以回收视图的责任是处理它接收到的点击事件。

这实际上使它更容易使用,特别是如果你有可以在多个地方点击的项目。


无论如何,检测点击一个RecyclerView项目是非常容易的。你所需要做的就是定义一个接口(如果你不使用Kotlin,在这种情况下你只需要传入一个lambda):

public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {
    private final Clicks clicks;

    public MyAdapter(Clicks clicks) {
        this.clicks = clicks;
    }

    private List<MyObject> items = Collections.emptyList();

    public void updateData(List<MyObject> items) {
        this.items = items;
        notifyDataSetChanged(); // TODO: use ListAdapter for diffing instead if you need animations
    }

    public interface Clicks {
        void onItemSelected(MyObject myObject, int position);
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {
        private MyObject myObject;    

        public MyViewHolder(View view) {
            super(view);
            // bind views
            view.setOnClickListener((v) -> {
                int adapterPosition = getBindingAdapterPosition();
                if(adapterPosition >= 0) {
                    clicks.onItemSelected(myObject, adapterPosition);
                }
            });
        }

        public void bind(MyObject myObject) {
            this.myObject = myObject;
            // bind data to views
        }
    }
}

Kotlin中的代码相同:

class MyAdapter(val itemClicks: (MyObject, Int) -> Unit): RecyclerView.Adapter<MyViewHolder>() {
    private var items: List<MyObject> = Collections.emptyList()

    fun updateData(items: List<MyObject>) {
        this.items = items
        notifyDataSetChanged() // TODO: use ListAdapter for diffing instead if you need animations
    }

    inner class MyViewHolder(val myView: View): RecyclerView.ViewHolder(myView) {
        private lateinit var myObject: MyObject

        init {
            // binds views
            myView.onClick {
                val adapterPosition = getBindingAdapterPosition()
                if(adapterPosition >= 0) {
                    itemClicks.invoke(myObject, adapterPosition)
                }
            }
        }

        fun bind(myObject: MyObject) {
            this.myObject = myObject
            // bind data to views
        }
    }
}

你不需要做的事情:

1)你不需要手动拦截触摸事件

2.)您不需要在子附加状态更改侦听器上添乱

3)你不需要RxJava中的PublishSubject/PublishRelay

只需使用点击侦听器。

其他回答

最简单的方法如下:

在Adapter类开始时声明全局变量:

// Store out here so we can resuse
private View yourItemView;

然后在onBindViewHolder方法中设置OnClickListener:

@Override
public void onBindViewHolder(BusinessAdapter.ViewHolder holder, int position) {

    // Set up the on click listener
    yourItemView.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            Toast.makeText(mContext,Integer.toString(position),Toast.LENGTH_SHORT).show();
        }
    });

}

其他答案都不正确。

如果您有一个pojo列表,并且希望从适配器外部单击检索一个pojo,那么这里有一种非常容易实现它的方法。

在你的适配器中,为点击事件创建一个监听器和一个方法来设置它:

public class MyAdapter extends RecyclerView.Adapter<SitesListAdapter.ViewHolder> {
...
private List<MyPojo> mMyPojos;
private static OnItemClickListener mOnItemClickListener;

...
public interface OnItemClickListener {
    public void onItemClick(MyPojo pojo);
}

...
public void setOnItemClickListener(OnItemClickListener onItemClickListener){
    mOnItemClickListener = onItemClickListener;
}
...

}

在你的ViewHolder中,实现onClickListener并创建一个类成员来临时存储视图所呈现的POJO(这是一个例子,创建一个setter会更好):

public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    public MyPojo mCurrentPojo;
    ...
    public ViewHolder(View view) {
        super(v);
        ...
        view.setOnClickListener(this); //You could set this on part of the layout too
    }

    ...
    @Override
    public void onClick(View view) {
        if(mOnItemClickListener != null && mCurrentPojo != null){
            mOnItemClickListener.onItemClick(mCurrentPojo);
        }
    }

回到你的适配器,当ViewHolder被绑定时设置当前POJO(如果当前视图没有,则设置为null):

@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
    final MyPojo currentPojo = mMyPojos.get(position); 
    holder.mCurrentPojo = currentPojo;
    ...

就是这样,现在你可以在你的fragment/activity中这样使用它:

    mMyAdapter.setOnItemClickListener(new mMyAdapter.OnItemClickListener() {
        @Override
        public void onItemClick(MyPojo pojo) {
            //Do whatever you want with your pojo here
        }
    });

是的,你可以

public ViewHolder onCreateViewHolder(ViewGroup parent,int viewType) {

    //inflate the view 

    View view = LayoutInflator.from(parent.getContext()).inflate(R.layout.layoutID,null);

    ViewHolder holder = new ViewHolder(view);

    //here we can set onClicklistener
    view.setOnClickListener(new  View.OnClickListeener(){
        public void onClick(View v)
        {
            //action
        }
    });

return holder;

如何把它们放在一起举例…

onClick() handling Cursor - RecyclerView ViewHolder types public class OrderListCursorAdapter extends CursorRecyclerViewAdapter<OrderListCursorAdapter.ViewHolder> { private static final String TAG = OrderListCursorAdapter.class.getSimpleName(); private static final int ID_VIEW_HOLDER_ACTUAL = 0; private static final int ID_VIEW_HOLDER = 1; public OrderListCursorAdapter(Context context, Cursor cursor) { super(context, cursor); } public static class ViewHolderActual extends ViewHolder { private static final String TAG = ViewHolderActual.class.getSimpleName(); protected IViewHolderClick listener; protected Button button; public ViewHolderActual(View v, IViewHolderClick listener) { super(v, listener); this.listener = listener; button = (Button) v.findViewById(R.id.orderList_item_button); button.setOnClickListener(this); } public void initFromData(OrderData data) { Log.d(TAG, "><initFromData(data=" + data + ")"); orderId = data.getId(); vAddressStart.setText(data.getAddressStart()); vAddressEnd.setText(data.getAddressEnd()); } @Override public void onClick(View view) { if (view instanceof Button) { listener.onButtonClick((Button) view, getPosition(), this); } else { super.onClick(view); } } public interface IViewHolderClick extends ViewHolder.IViewHolderClick { public void onButtonClick(Button button, int position, ViewHolder viewHolder); } } public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener { private static final String TAG = ViewHolder.class.getSimpleName(); protected long orderId; protected IViewHolderClick listener; protected TextView vAddressStart; protected TextView vAddressEnd; protected TextView vStatus; public ViewHolder(View v, IViewHolderClick listener) { super(v); this.listener = listener; v.setOnClickListener(this); vAddressStart = (TextView) v.findViewById(R.id.addressStart); vAddressEnd = (TextView) v.findViewById(R.id.addressEnd); vStatus = (TextView) v.findViewById(R.id.status); } public void initFromData(OrderData data) { Log.d(TAG, "><initFromData(data=" + data + ")"); orderId = data.getId(); vAddressStart.setText(data.getAddressStart()); vAddressEnd.setText(data.getAddressEnd()); } public long getOrderId() { return orderId; } @Override public void onClick(View view) { listener.onCardClick(view, getPosition(), this); } public interface IViewHolderClick { public void onCardClick(View view, int position, ViewHolder viewHolder); } } @Override public int getItemViewType(int position) { return position == 0 ? ID_VIEW_HOLDER_ACTUAL : ID_VIEW_HOLDER; } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { Log.d(TAG, ">>onCreateViewHolder(parent=" + parent + ", viewType=" + viewType + ")"); ViewHolder result; switch (viewType) { case ID_VIEW_HOLDER_ACTUAL: { View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_layout_actual, parent, false); result = new ViewHolderActual(itemView, new ViewHolderActual.IViewHolderClick() { @Override public void onCardClick(View view, int position, ViewHolder viewHolder) { Log.d(TAG, "><onCardClick(view=" + view + ", position=" + position + ", viewHolder=" + viewHolder + ")"); Intent intent = new Intent(view.getContext(), OrderDetailActivity.class); intent.putExtra(OrderDetailActivity.ARG_ORDER_ID, viewHolder.getOrderId()); view.getContext().startActivity(intent); } @Override public void onButtonClick(Button button, int position, ViewHolder viewHolder) { Log.d(TAG, "><onButtonClick(button=" + button + ", position=" + position + ", viewHolder=" + viewHolder + ")"); Intent intent = new Intent(button.getContext(), OrderMapActivity.class); intent.putExtra(OrderMapActivity.ARG_ORDER_ID, viewHolder.getOrderId()); button.getContext().startActivity(intent); } }); break; } case ID_VIEW_HOLDER: default: { View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_layout, parent, false); result = new ViewHolder(itemView, new ViewHolder.IViewHolderClick() { @Override public void onCardClick(View view, int position, ViewHolder viewHolder) { Log.d(TAG, "><onCardClick(view=" + view + ", position=" + position + ", viewHolder=" + viewHolder + ")"); Intent intent = new Intent(view.getContext(), OrderDetailActivity.class); intent.putExtra(OrderDetailActivity.ARG_ORDER_ID, viewHolder.getOrderId()); view.getContext().startActivity(intent); } }); break; } } Log.d(TAG, "<<onCreateViewHolder(parent=" + parent + ", viewType=" + viewType + ")= " + result); return result; } @Override public void onBindViewHolder(ViewHolder viewHolder, Cursor cursor) { Log.d(TAG, "><onBindViewHolder(viewHolder=" + viewHolder + ", cursor=" + cursor + ")"); final OrderData orderData = new OrderData(cursor); viewHolder.initFromData(orderData); } }

 main_recyclerview.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
        @Override
        public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e)
        {
            int position=rv.getChildAdapterPosition(rv.findChildViewUnder(e.getX(),e.getY()));

            switch (position)
            {
                case 0:
                {
                    wifi(position);
                    adapter2.notifyDataSetChanged();
                }
                break;

                case 1:
                {
                    sound(position);
                    adapter2.notifyDataSetChanged();
                }
                break;

                case 2:
                {
                    bluetooth(position);
                    adapter2.notifyDataSetChanged();
                }
                break;


            }
            return true;
        }

        @Override
        public void onTouchEvent(RecyclerView rv, MotionEvent e)
        {

        }

        @Override
        public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

        }
    });