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?
如果你想添加onClick()到项目的子视图，例如，项目中的按钮，我发现你可以很容易地在你自己的RecyclerView的onCreateViewHolder()中做到这一点。适配器就像这样:
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater
.from(parent.getContext())
.inflate(R.layout.cell, null);
Button btn = (Button) v.findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//do it
}
});
return new MyViewHolder(v);
}
我不知道这是不是一个好方法，但它很有效。如果有人有更好的想法，很高兴告诉我并纠正我的答案!：）
看看我的方法:
首先像这样声明一个接口:
/**
* Interface used for delegating item click events in a {@link android.support.v7.widget.RecyclerView}
* Created by Alex on 11/28/2015.
*/
public interface OnRecyclerItemClickListener<T> {
/**
* Called when a click occurred inside a recyclerView item view
* @param view that was clicked
* @param position of the clicked view
* @param item the concrete data that is displayed through the clicked view
*/
void onItemClick(View view, int position, T item);
}
然后创建适配器:
public class CustomRecyclerAdapter extends RecyclerView.Adapter {
private class InternalClickListener implements View.OnClickListener{
@Override
public void onClick(View v) {
if(mRecyclerView != null && mItemClickListener != null){
// find the position of the item that was clicked
int position = mRecyclerView.getChildAdapterPosition(v);
Data data = getItem(position);
// notify the main listener
mItemClickListener.onItemClick(v, position, data);
}
}
}
private final OnRecyclerItemClickListener mItemClickListener;
private RecyclerView mRecyclerView;
private InternalClickListener mInternalClickListener;
/**
*
* @param itemClickListener used to trigger an item click event
*/
public PlayerListRecyclerAdapter(OnRecyclerItemClickListener itemClickListener){
mItemClickListener = itemClickListener;
mInternalClickListener = new InternalClickListener();
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item, parent, false);
v.setOnClickListener(mInternalClickListener);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
// do your binding here
}
@Override
public int getItemCount() {
return mDataSet.size();
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
mRecyclerView = recyclerView;
}
@Override
public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
super.onDetachedFromRecyclerView(recyclerView);
mRecyclerView = null;
}
public Data getItem(int position){
return mDataset.get(position);
}
}
现在让我们看看如何从一个片段中整合这个:
public class TestFragment extends Fragment implements OnRecyclerItemClickListener<Data>{
private RecyclerView mRecyclerView;
@Override
public void onItemClick(View view, int position, Data item) {
// do something
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.test_fragment, container, false);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
mRecyclerView = view.findViewById(idOfTheRecycler);
mRecyclerView .setAdapter(new CustomRecyclerAdapter(this));
}
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。
