有人使用RecyclerView找到了一种方法来设置一个onClickListener的项目在RecyclerView? 我想设置一个监听器为每个项目的布局,但这似乎有点太麻烦了 我确信有一种方法让RecyclerView监听onClick事件,但我不能完全弄清楚。
当前回答
别白费力气了!这个特定用例的代码包含在Android Studio附带的Master/Detail Flow启动器项目中。
从Android Studio选择:
文件>新建>新建项目.... 在Phone and Tablet选项卡中选择如下所示的Master/Detail Flow。
用Kotlin或Java创建项目。 利润。
我不会在这里包括谷歌的ootb演示项目的代码,但我会概述谷歌提供的示例中的主要设计方法:
the item OnClickListener is created ONLY ONCE, and is assigned to a field in your RecyclerView.Adapter implementation. in the onBindViewHolder() you should set the same, pre-created onClickListener object on your ViewHolder instance with holder.itemView.setOnClickListener(mOnClickListener) (AVOID creating a new instance on every method call!); if you need to capture clicks on some specific elements inside the ViewHolder then extend ViewHolder and expose the elements you need as fields so that you can attach whatever listeners you need in onBindViewHolder() — and once again, do NOT re-create the listeners on every method call — initialise them as instance fields and attach them as needed. you can use .setTag() in order to pass state to your viewHolder, e.g. holder.itemView.setTag(mValues.get(position)); as used in the demo.
其他回答
对我来说,这是最好的方法:
class YourRecyclerAdapter extends RecyclerView.Adapter<ContactViewHolder> implements View.OnClickListener {
...
@Override
public void onClick(View view) {
int itemPosition = vRecycle.getChildPosition(view);
//And use itemPosition to get the item from your collection. This way you dont restrain the ViewHolder with a OnClick callback
}
...
}
在kotlin中使用构造函数实现
初始化你的RecyclerView构造函数,如下所示:
class ListAdapter(
c: Context,
private var list: List<Project>,
private val itemClick: (Project) -> Unit
) : RecyclerView.Adapter<ListAdapter.ViewHolder>()
在onCreateViewHolder中使用itemClick返回:
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int):ProjectViewHolder {
val view = inflater.inflate(R.layout.list_item, parent, false)
return ViewHolder(view, itemClick)
}
你的onBindViewHolder:
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.bindProject(list[position])
}
然后用ViewHolder类创建bindProject函数。
class ViewHolder(
view: View,
private val itemClick: (Project) -> Unit
) : RecyclerView.ViewHolder(view) {
private val clientTextCount = 7
val titleTextView: TextView = view.projectTitleTextView
fun bindProject(project: Project) {
with(project) {
titleTextView.text = name
itemView.setOnClickListener { itemClick(this) }
}
}
}
最后在您的活动中用lazy初始化适配器
private val adapter: ListAdapter by lazy {
ListAdapter(this, projectList, {
// Here you can implement your onClick function.
})
}
在适配器中为RecyclerView添加新列表初始化以下方法:
fun setProjects(projects: List<Project>) {
projectList = projects
notifyDataSetChanged()
}
在你的活动中调用setProjects方法:
adapter.setProjects(projects)
就是这样。
太简单和有效了。
而不是实现接口视图。OnClickListener内的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();
}
}
由于API已经发生了根本性的变化,如果你要为每个项目创建一个OnClickListener,这不会让我感到惊讶。不过也没那么麻烦。在你的RecyclerView的实现中。适配器<MyViewHolder>,你应该有:
private final OnClickListener mOnClickListener = new MyOnClickListener();
@Override
public MyViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
View view = LayoutInflater.from(mContext).inflate(R.layout.myview, parent, false);
view.setOnClickListener(mOnClickListener);
return new MyViewHolder(view);
}
onClick方法:
@Override
public void onClick(final View view) {
int itemPosition = mRecyclerView.getChildLayoutPosition(view);
String item = mList.get(itemPosition);
Toast.makeText(mContext, item, Toast.LENGTH_LONG).show();
}
From most of the answers above, they seem to be setting their onclicklisteners to individual items. However, the solution am about to offer is very simple but yet not intuitive to many. Many are forgetting that the other components are always in a parent component which is used to display items in the List or Recycler views. This solution is just about setting a single onclick listener to this parent view and the turn is played. The solution also includes a way to pass the position of the item being clicked on from the list or recycler view. Here, our main rootview is a CardView from the android support library. Here is sample code
public class ListAdapter extends RecyclerView.Adapter<ListAdapter.ViewHolder> {
public static final String LOG_TAG = ListAdapter.class.getSimpleName();
private Cursor mDataset;
private Context mContext;
private ViewHolder mViewHolder;
// Provide a suitable constructor (depends on the kind of dataset)
public ListAdapter(Context context, Cursor Dataset) {
mDataset = Dataset;
mContext = context;
}
// Create new views (invoked by the layout manager)
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_business_view, parent, false);
mViewHolder = new ViewHolder(v);
return mViewHolder;
}
public void setData(Cursor newdata) {
this.mDataset = newdata;
}
// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
//Bind data to other items here. To save time, i have ommited that.
//here is where we attach a click listerner for an item in the recycler list rather than for each element of a given item.
holder.card.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(mContext, " Just cliked item at position " + itemPosition, Toast.LENGTH_LONG).show();
}
});
}
}
// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
if (null != mDataset) {
return mDataset.getCount();
}
return 0;
}
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder
public static class ViewHolder extends RecyclerView.ViewHolder{
// each data item is just a string in this case
public final TextView mBusinesssName; // View for the business name
public final TextView mBusinessCategory; //View for the category name
public final ImageView businessImage; // View for the business category image Image
public final TextView mBusinessDistance; // View for the distance
public final CardView card;
public ViewHolder(View view) {
super(view);
mBusinesssName = (TextView) view.findViewById(R.id.list_item_name_textview);
mBusinessCategory = (TextView) view.findViewById(R.id.list_item_category_textview);
mBusinessDistance = (TextView) view.findViewById(R.id.list_item_dist_textview);
businessImage = (ImageView) view.findViewById(R.id.list_item_icon);
card = (CardView) view.findViewById(R.id.card_view);
}
}
}
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