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?
检查这一个，我已经实现了所有的事情与适当的方式
RecyclerViewHolder类
public class RecyclerViewHolder extends RecyclerView.ViewHolder {
//view holder is for girdview as we used in the listView
public ImageView imageView,imageView2;
public RecyclerViewHolder(View itemView) {
super(itemView);
this.imageView=(ImageView)itemView.findViewById(R.id.image);
}
}
适配器
public class RecyclerView_Adapter extends RecyclerView.Adapter<RecyclerViewHolder> {
//RecyclerView will extend to recayclerview Adapter
private ArrayList<ModelClass> arrayList;
private Context context;
private static RecyclerViewClickListener itemListener;
//constructor of the RecyclerView Adapter
RecyclerView_Adapter(Context context,ArrayList<ModelClass> arrayList,RecyclerViewClickListener itemListener){
this.context=context;
this.arrayList=arrayList;
this.itemListener=itemListener;
}
@Override
public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
//this method will inflate the custom layout and return as viewHolder
LayoutInflater layoutInflater=LayoutInflater.from(parent.getContext());
ViewGroup mainGroup=(ViewGroup) layoutInflater.inflate(R.layout.single_item,parent,false);
RecyclerViewHolder listHolder=new RecyclerViewHolder(mainGroup);
return listHolder;
}
@Override
public void onBindViewHolder(RecyclerViewHolder holder, final int position) {
final ModelClass modelClass=arrayList.get(position);
//holder
RecyclerViewHolder mainHolder=(RecyclerViewHolder)holder;
//convert the drawable image into bitmap
Bitmap image= BitmapFactory.decodeResource(context.getResources(),modelClass.getImage());
//set the image into imageView
mainHolder.imageView.setImageBitmap(image);
//to handle on click event when clicked on the recyclerview item and
// get it through the RecyclerViewHolder class we have defined the views there
mainHolder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//get the position of the image which is clicked
itemListener.recyclerViewListClicked(v,position);
}
});
}
@Override
public int getItemCount() {
return (null!=arrayList?arrayList.size():0);
}
}
的接口
public interface RecyclerViewClickListener {
//this is method to handle the event when clicked on the image in Recyclerview
public void recyclerViewListClicked(View v,int position);
}
//and to call this method in activity
RecyclerView_Adapter adapter=new RecyclerView_Adapter(Wallpaper.this,arrayList,this);
recyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();
@Override
public void recyclerViewListClicked(View v,int position){
imageView.setImageResource(wallpaperImages[position]);
}
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。
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!：）
