[英]Android Dont know how to fix this index out of bounds exception FirebaseRecyclerview
我收到此错误,我不知道如何解决
java.lang.IndexOutOfBoundsException:Index:2,Size:2 at com.tijdelijk.java.util.ArrayList.get(ArrayList.java:411)。com.tijdelijk.firebasetest.Start $ 1.populateViewHolder(Start.java:69) .firebasetest.Start $ 1.populateViewHolder(Start.java:64)
我正在使用Firebase数据库,并且基于CategoryId,我将这些项目放在SubCategories的数组列表中,我的代码是:
public class CategoryFragment extends Fragment {
View myFragment;
RecyclerView listCategory;
RecyclerView.LayoutManager layoutManager;
FirebaseRecyclerAdapter<Category, CategoryViewHolder> adapter;
FirebaseDatabase database;
DatabaseReference categories;
DatabaseReference subCategory;
public static CategoryFragment newInstance() {
CategoryFragment fragment = new CategoryFragment();
return fragment;
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
database = FirebaseDatabase.getInstance();
categories = database.getReference("Category");
subCategory = database.getReference("SubCategory");
}
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
myFragment = inflater.inflate(R.layout.fragment_category, container, false);
listCategory = (RecyclerView) myFragment.findViewById(R.id.listCategory);
listCategory.setHasFixedSize(true);
layoutManager = new LinearLayoutManager(container.getContext());
listCategory.setLayoutManager(layoutManager);
loadCategories();
return myFragment;
}
private void loadCategories() {
adapter = new FirebaseRecyclerAdapter<Category, CategoryViewHolder>(
Category.class,
R.layout.category_layout,
CategoryViewHolder.class,
categories
) {
@Override
protected void populateViewHolder(CategoryViewHolder viewHolder, final Category model, int position) {
viewHolder.category_name.setText(model.getName());
Picasso.with(getActivity())
.load(model.getImage())
.into(viewHolder.category_image);
viewHolder.setItemClickListener(new ItemClickListener() {
@Override
public void onClick(View view, int position, boolean isLongClick) {
Intent startGame = new Intent(getActivity(), Start.class);
Common.categoryId = adapter.getRef(position).getKey();
loadSubCategory(Common.categoryId);
startActivity(startGame);
}
});
}
};
adapter.notifyDataSetChanged();
listCategory.setAdapter(adapter);
}
private void loadSubCategory(String categoryId) {
//Clear list if there are old subCategory
if (Common.subCategoryList.size() > 0) {
Common.subCategoryList.clear();
}
subCategory.orderByChild("CategoryId").equalTo(categoryId)
.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
SubCategory ques = postSnapshot.getValue(SubCategory.class);
Common.subCategoryList.add(ques);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
在此活动中,我还想显示一个recyclerview,但是这次基于我从categoryfragment获得的arraylist,这是我的代码:
public class Start extends AppCompatActivity {
FirebaseDatabase database;
DatabaseReference subCategory;
FirebaseRecyclerAdapter<SubCategory, SubCategoryViewHolder> adapter;
RecyclerView listSubCategory;
RecyclerView.LayoutManager layoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_start);
database = FirebaseDatabase.getInstance();
subCategory = database.getReference("SubCategory");
listSubCategory = findViewById(R.id.listSubCategory);
listSubCategory.setHasFixedSize(true);
layoutManager = new LinearLayoutManager(getBaseContext());
listSubCategory.setLayoutManager(layoutManager);
loadSubCategories();
adapter.notifyDataSetChanged();
listSubCategory.setAdapter(adapter);
}
private void loadSubCategories() {
adapter = new FirebaseRecyclerAdapter<SubCategory, SubCategoryViewHolder>(
SubCategory.class,
R.layout.subcategory_layout,
SubCategoryViewHolder.class,
subCategory
) {
@Override
protected void populateViewHolder(SubCategoryViewHolder viewHolder, SubCategory model, int position) {
viewHolder.subcategory_nlname.setText(Common.subCategoryList.get(position).getLatijnseNaam());
viewHolder.subcategory_ltname.setText(Common.subCategoryList.get(position).getNederlandseNaam());
viewHolder.setItemClickListener(new ItemClickListener() {
@Override
public void onClick(View view, int position, boolean isLongClick) {
Intent startGame = new Intent(Start.this, Start.class);
Common.categoryId = adapter.getRef(position).getKey();
startActivity(startGame);
}
});
}
};
}
}
这是我的观察者:
public class SubCategoryViewHolder extends RecyclerView.ViewHolder
implements View.OnClickListener{
public TextView subcategory_nlname;
public TextView subcategory_ltname;
private ItemClickListener itemClickListener;
public SubCategoryViewHolder(View itemView) {
super(itemView);
subcategory_ltname = itemView.findViewById(R.id.latijnse_naam);
subcategory_nlname = itemView.findViewById(R.id.nederlandse_naam);
// itemView.findViewById(R.id.btnPlay).setOnClickListener(this);
}
public void setItemClickListener(ItemClickListener itemClickListener) {
this.itemClickListener = itemClickListener;
}
@Override
public void onClick(View view) {
itemClickListener.onClick(view,getAdapterPosition(),false);
}
}
IndexOutOfBoundException意味着您正在尝试访问位于数组索引之外的值。
在您的情况下,您有两个值的数组。 因此,您具有键0和1。如错误中所述,您的代码正在尝试访问不存在的索引2。
您必须检查是否正在访问数组值范围内的索引。
祝你有美好的一天。
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