RecyclerView获取按位置查看 [英] RecyclerView get View by position
问题描述
我有一个RecyclerView，每个CardView包含一个TextView和一个ImageView.每当我单击一个项目时，我都希望将图像可见性设置为VISIBLE，并将上次单击的项目图像的可见性设置为INVISIBLE.
I have a RecyclerView and each CardView contains a TextView and an ImageView. Whenever I click an item, I want to set the image visibility to VISIBLE and to set the previous clicked item image's visibility to INVISIBLE.
这是我的适配器类:
public class CategoryAdapter extends RecyclerView.Adapter<CategoryAdapter.ViewHolder>{
private Context context;
private List<Category> lista;
private LayoutInflater layoutInflater;
private IncomeCategoryActivity activity;
private static final int CATEGORY_REQUEST=6;
private static final int ITEM_EDIT=1;
private static final int ITEM_DELETE=2;
private static final int EDIT_REQUEST=7;
private int current_pos=-1;
public CategoryAdapter(List<Category> lista, Context context, IncomeCategoryActivity activity) {
this.context = context;
this.lista = lista;
this.activity=activity;
layoutInflater=LayoutInflater.from(context);
}
@Override
public CategoryAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view=layoutInflater.inflate(R.layout.category_layout, parent, false);
ViewHolder viewHolder=new ViewHolder(view, activity);
return viewHolder;
}
@Override
public void onBindViewHolder(CategoryAdapter.ViewHolder holder, int position) {
holder.imageView.setImageURI(lista.get(position).getUri());
holder.textView.setText(lista.get(position).getCategory());
holder.position = position;
holder.category=lista.get(position);
if(holder.category.isChecked()==true){
holder.imageViewCheck.setVisibility(View.VISIBLE);
current_pos=position;
} else {
holder.imageViewCheck.setVisibility(View.INVISIBLE);
}
}
@Override
public int getItemCount() {
return lista.size();
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnCreateContextMenuListener, MenuItem.OnMenuItemClickListener{
public ImageView imageView;
public TextView textView;
public ImageView imageViewCheck;
public int position;
public Category category;
public IncomeCategoryActivity activity;
public ViewHolder(View itemView, IncomeCategoryActivity activity) {
super(itemView);
this.activity=activity;
imageView=itemView.findViewById(R.id.customCategoryImageView);
textView=itemView.findViewById(R.id.customCategoryTextView);
imageViewCheck=itemView.findViewById(R.id.customCheckImageView);
itemView.setOnClickListener(this);
itemView.setOnCreateContextMenuListener(this);
}
@Override
public void onClick(View v) {
String aux=textView.getText().toString();
if(aux=="CATEGORIE NOUĂ"){
Intent intent=new Intent(context, CustomIncomeActivity.class);
activity.startActivityForResult(intent, CATEGORY_REQUEST);
}
else{
imageViewCheck.setVisibility(View.VISIBLE);
int pozitie_check=getLayoutPosition();
Intent intent=new Intent(context, AddIncomeActivity.class);
intent.putExtra("categorie_venit", aux);
intent.putExtra("position_check", pozitie_check);
activity.setResult(Activity.RESULT_OK, intent);
activity.finish();
}
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
menu.setHeaderTitle("Selectează acțiunea");
MenuItem edit=menu.add(0, ITEM_EDIT, 0, "Modifică");
MenuItem delete=menu.add(0, ITEM_DELETE, 0, "Șterge");
edit.setOnMenuItemClickListener(this);
delete.setOnMenuItemClickListener(this);
}
@Override
public boolean onMenuItemClick(MenuItem item) {
int position=getLayoutPosition();
if (item.getGroupId() == 0) {
if(item.getItemId()==ITEM_EDIT){
Category category=lista.get(position);
Intent intent=new Intent(activity, CustomIncomeActivity.class);
intent.putExtra("edit_icon", category.getUri());
intent.putExtra("edit_category", category.getCategory());
intent.putExtra("list_position", position);
activity.startActivityForResult(intent, EDIT_REQUEST);
}
else if(item.getItemId()==ITEM_DELETE){
lista.remove(position);
notifyDataSetChanged();
}
}
return true;
}
此刻，每当我单击一个项目时，RecyclerView上都有两个可见的图像:被单击项目的图像和上一个被单击项目的图像.我认为我需要按其位置获取上一个视图，并将可见性手动设置为不可见".
At this moment, whenever I click an item, there are two images VISIBLE on the RecyclerView: the clicked item's image and the previous clicked item's image. I think I need to get the previous View by its position and to manually set the visibility to INVISIBLE.
推荐答案
recycleView.getChildCount()和recycleView_parent.getChildAt()仅提供适配器项，该项仅显示在屏幕上.
这意味着，如果您的列表中有200个项目，并且屏幕上仅显示5个项目，那么借助于 recycleView
recycleView.getChildCount() and recycleView_parent.getChildAt() only gives the Adapter items which is shows only screen .
that means if your list has 200 items and the only 5 items shows on screen so we can find only 5 item with the help of recycleView
我正在使用一个简单的技巧解决问题.
i am using one simple trick to solve the issue.
-
您可以定义保存您的 holder对象
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
ArrayList<Model> dataList;
Context context;
HashMap<Integer,ViewHolder> holderlist;
public MyAdapter(ArrayList<Model> dataList, Context context) {
this.context = context;
this.dataList = dataList;
holderlist = new HashMap<>();
}
，然后将其保存在Hashmap中
and after that to save the holder in Hashmap
public void onBindViewHolder(final ViewHolder holder, final int position) {
if(!holderlist.containsKey(position)){
holderlist.put(position,holder);
}
在适配器中创建方法.
create a method in Adapter.
public MyListAdapter.ViewHolder getViewByPosition(int position){ 返回holderlist.get(位置); }
public MyListAdapter.ViewHolder getViewByPosition(int position) { return holderlist.get(position); }
在您的活动中或需要时调用此方法.
call this method from your Activity or whenever you want.
for (int i = 0; i < datalList.size(); i++) {
MyAdapter.ViewHolder holder = ((MyAdapter)recycleView.getAdapter()).getViewByPosition(i);
View view = holder.itemView;
TextView tv = view.findViewById(R.id.tv);
}
这篇关于RecyclerView获取按位置查看的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
