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?
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。
伙计们，在你们的主要活动中使用这个代码。非常有效的方法
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.users_list);
UsersAdapter adapter = new UsersAdapter(users, this);
recyclerView.setAdapter(adapter);
adapter.setOnCardClickListner(this);
下面是适配器类。
public class UsersAdapter extends RecyclerView.Adapter<UsersAdapter.UserViewHolder> {
private ArrayList<User> mDataSet;
OnCardClickListner onCardClickListner;
public UsersAdapter(ArrayList<User> mDataSet) {
this.mDataSet = mDataSet;
}
@Override
public UserViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.user_row_layout, parent, false);
UserViewHolder userViewHolder = new UserViewHolder(v);
return userViewHolder;
}
@Override
public void onBindViewHolder(UserViewHolder holder, final int position) {
holder.name_entry.setText(mDataSet.get(position).getUser_name());
holder.cardView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onCardClickListner.OnCardClicked(v, position);
}
});
}
@Override
public int getItemCount() {
return mDataSet.size();
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
public static class UserViewHolder extends RecyclerView.ViewHolder {
CardView cardView;
TextView name_entry;
public UserViewHolder(View itemView) {
super(itemView);
cardView = (CardView) itemView.findViewById(R.id.user_layout);
name_entry = (TextView) itemView.findViewById(R.id.name_entry);
}
}
public interface OnCardClickListner {
void OnCardClicked(View view, int position);
}
public void setOnCardClickListner(OnCardClickListner onCardClickListner) {
this.onCardClickListner = onCardClickListner;
}
}
在此之后，您将在您的活动中获得这个覆盖方法。
@Override
public void OnCardClicked(View view, int position) {
Log.d("OnClick", "Card Position" + position);
}
在这里，你可以处理多个点击看到下面的代码，这是非常有效的
public class RVNewsAdapter extends RecyclerView.Adapter<RVNewsAdapter.FeedHolder> {
private Context context;
List<News> newsList;
// Allows to remember the last item shown on screen
private int lastPosition = -1;
public RVNewsAdapter(List<News> newsList, Context context) {
this.newsList = newsList;
this.context = context;
}
public static class FeedHolder extends RecyclerView.ViewHolder implements OnClickListener {
ImageView img_main;
TextView tv_title;
Button bt_facebook, bt_twitter, bt_share, bt_comment;
public FeedHolder(View itemView) {
super(itemView);
img_main = (ImageView) itemView.findViewById(R.id.img_main);
tv_title = (TextView) itemView.findViewById(R.id.tv_title);
bt_facebook = (Button) itemView.findViewById(R.id.bt_facebook);
bt_twitter = (Button) itemView.findViewById(R.id.bt_twitter);
bt_share = (Button) itemView.findViewById(R.id.bt_share);
bt_comment = (Button) itemView.findViewById(R.id.bt_comment);
img_main.setOnClickListener(this);
bt_facebook.setOnClickListener(this);
bt_twitter.setOnClickListener(this);
bt_comment.setOnClickListener(this);
bt_share.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == bt_comment.getId()) {
Toast.makeText(v.getContext(), "Comment " , Toast.LENGTH_SHORT).show();
} else if (v.getId() == bt_facebook.getId()) {
Toast.makeText(v.getContext(), "Facebook " , Toast.LENGTH_SHORT).show();
} else if (v.getId() == bt_twitter.getId()) {
Toast.makeText(v.getContext(), "Twitter " , Toast.LENGTH_SHORT).show();
} else if (v.getId() == bt_share.getId()) {
Toast.makeText(v.getContext(), "share " , Toast.LENGTH_SHORT).show();
}
else {
Toast.makeText(v.getContext(), "ROW PRESSED = " + String.valueOf(getAdapterPosition()), Toast.LENGTH_SHORT).show();
}
}
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
@Override
public FeedHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.feed_row, parent, false);
FeedHolder feedHolder = new FeedHolder(view);
return feedHolder;
}
@Override
public void onBindViewHolder(FeedHolder holder, int position) {
holder.tv_title.setText(newsList.get(position).getTitle());
// Here you apply the animation when the view is bound
setAnimation(holder.img_main, position);
}
@Override
public int getItemCount() {
return newsList.size();
}
/**
* Here is the key method to apply the animation
*/
private void setAnimation(View viewToAnimate, int position) {
// If the bound view wasn't previously displayed on screen, it's animated
if (position > lastPosition) {
Animation animation = AnimationUtils.loadAnimation(context, android.R.anim.slide_in_left);
viewToAnimate.startAnimation(animation);
lastPosition = position;
}
}
}
而不是实现接口视图。OnClickListener内部视图持有人或创建和接口和实现接口在您的活动..
我使用这段代码简单的OnClickListener实现。
public static class SimpleStringRecyclerViewAdapter
extends RecyclerView.Adapter<SimpleStringRecyclerViewAdapter.ViewHolder> {
// Your initializations goes here...
private List<String> mValues;
public static class ViewHolder extends RecyclerView.ViewHolder {
//create a variable mView
public final View mView;
/*All your row widgets goes here
public final ImageView mImageView;
public final TextView mTextView;*/
public ViewHolder(View view) {
super(view);
//Initialize it here
mView = view;
/* your row widgets initializations goes here
mImageView = (ImageView) view.findViewById(R.id.avatar);
mTextView = (TextView) view.findViewById(android.R.id.text1);*/
}
}
public String getValueAt(int position) {
return mValues.get(position);
}
public SimpleStringRecyclerViewAdapter(Context context, List<String> items) {
mBackground = mTypedValue.resourceId;
mValues = items;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item, parent, false);
view.setBackgroundResource(mBackground);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(final ViewHolder holder, int position) {
holder.mBoundString = mValues.get(position);
holder.mTextView.setText(mValues.get(position));
//Here it is simply write onItemClick listener here
holder.mView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Context context = v.getContext();
Intent intent = new Intent(context, ExampleActivity.class);
context.startActivity(intent);
}
});
}
@Override
public int getItemCount() {
return mValues.size();
}
}
