在滑动ViewPager时IndexOutOfBoundsException

Question

当我在ViewPager上的卡片之间滚动时，我的应用程序崩溃了，这是我得到的错误:

. lang。IndexOutOfBoundsException: index=5 count=4">

我完全不知道如何修复索引错误，但我认为它来自于我已经设置的ArrayList。

适配器类:

public class DashboardFlavorAdapter extends PagerAdapter {
private Context context;
private ArrayList<DashboardFlavorModel> modelArrayList;
public DashboardFlavorAdapter(Context context, ArrayList<DashboardFlavorModel> modelArrayList) {
this.context = context;
this.modelArrayList = modelArrayList;
}
@Override
public int getCount() {
return modelArrayList.size();
}
@Override
public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
return view.equals(object);
}
@NonNull
@Override
public Object instantiateItem(@NonNull ViewGroup container, int position) {
//inflate layout flavor_item.xml
View view = LayoutInflater.from(context).inflate(R.layout.flavor_item, container, false);
//initialize UID views from flavor_item.xml
ImageView imageIv = view.findViewById(R.id.imageIv);
TextView flavorTv = view.findViewById(R.id.flavorTv);
TextView quantityTv = view.findViewById(R.id.quantityTv);
ImageButton minusbutton = (ImageButton) view.findViewById(R.id.minusbutton);
ImageButton plusbutton = (ImageButton) view.findViewById(R.id.plusbutton);
//getting data
DashboardFlavorModel model = modelArrayList.get(position);
String title = model.getTitle();
int image = model.getImage();
int count = model.getCount();
//setting data
imageIv.setImageResource(image);
flavorTv.setText(title);
quantityTv.setText(String.valueOf(count));
//listener
minusbutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (count>0){
model.setCount(count-1);
} else if (count ==0){
Snackbar message = Snackbar.make(view, "You cannot have less than 0 QTY",Snackbar.LENGTH_LONG).setAction("UNDO", new View.OnClickListener() {
@Override
public void onClick(View view) {}
});
message.show();
model.setCount(count);
}

}
});
plusbutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
model.setCount(count+1);
}
});

//Logcat also linked this line of code as part of the issue
container.addView(view, position);
return view;
}
@Override
public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
container.removeView((View)object);
}
}

每个"卡片"组件的getter +setter的模型类:

public class DashboardFlavorModel {
String title;
int image,count;
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public int getImage() {
return image;
}
public void setImage(int image) {
this.image = image;
}

这是我启动ViewPager的片段类:

public class DashboardFragment extends Fragment {
//calendar
private FragmentDashboardBinding binding;
private Button btn_date;
private DatePickerDialog.OnDateSetListener dateSetListener;
//flavor cards
private ViewPager viewPager;
private ArrayList<DashboardFlavorModel> modelArrayList;
private DashboardFlavorAdapter dashboardFlavorAdapter;

public View onCreateView(@NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
DashboardViewModel dashboardViewModel =
new ViewModelProvider(this).get(DashboardViewModel.class);
binding = FragmentDashboardBinding.inflate(inflater, container, false);
View root = binding.getRoot();
//final TextView textView = binding.textDashboard;
//dashboardViewModel.getText().observe(getViewLifecycleOwner(), textView::setText);
//button for *DELIVERYDATE*
btn_date = root.findViewById(R.id.datebutton);
btn_date.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final Calendar c = Calendar.getInstance();
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);
//Theme_Holo_Dialog for spinner calendar
DatePickerDialog dialog = new DatePickerDialog(getContext(), android.R.style.Theme_DeviceDefault_Dialog,dateSetListener, year , month , day);
dialog.show();
}
});
//date button listener
dateSetListener = (datePicker, y, m, d) -> {
m = m+1;
String date = d+"/"+m+"/"+y;
btn_date.setText("Deliver by: " +date);
};

//initialize UI views
viewPager = (ViewPager) root.findViewById(R.id.flavorsVp);
loadCards();
return root;
}
private void loadCards(){
//initialize list
modelArrayList = new ArrayList<>();
//adding items to list
modelArrayList.add(new DashboardFlavorModel(
"Red date",
R.drawable.flavor1,
0));
modelArrayList.add(new DashboardFlavorModel(
"Red date (NO sugar)",
R.drawable.flavor2,
0));
modelArrayList.add(new DashboardFlavorModel(
"Red date with LONGAN",
R.drawable.flavor3,
0));
modelArrayList.add(new DashboardFlavorModel(
"Red date with LONGAN (NO sugar)",
R.drawable.flavor4,
0));
modelArrayList.add(new DashboardFlavorModel(
"Osmanthus flower",
R.drawable.flavor1,
0));
modelArrayList.add(new DashboardFlavorModel(
"Osmanthus flower (NO sugar)",
R.drawable.flavor2,
0));
modelArrayList.add(new DashboardFlavorModel(
"Ginseng",
R.drawable.flavor3,
0));
modelArrayList.add(new DashboardFlavorModel(
"Pandan",
R.drawable.flavor4,
0));
modelArrayList.add(new DashboardFlavorModel(
"Cane sugar",
R.drawable.flavor1,
0));
//setup adapter
dashboardFlavorAdapter = new DashboardFlavorAdapter(getContext(),modelArrayList);
//set adapter to viewpager
viewPager.setAdapter(dashboardFlavorAdapter);
//set default padding from left/right
viewPager.setPadding(100,0,100,0);

}

@Override
public void onDestroyView() {
super.onDestroyView();
binding = null;
}
}

Answer 1

替换onDestroyMethod.

@Override
public void destroyItem(@NonNull ViewGroup container, int position, @NonNull 
Object object) {
//        super.destroyItem(container, position, object);
}