java - 从ArrayList <Form>中删除会引发UnsupportedOperationException

我正在开发一个Android 3.1应用程序。我已经使用ArrayList创建了自定义ArrayAdapter。 Form是具有两个字段的自定义类：name和FormId。这是我的ArrayAdapter代码：public class FormAdapter extends ArrayAdapter<Form>{ private Context context; private int layoutResourceId; private List<Form> forms; private ArrayList<Integer> checkedItemsPosition; private Button downloadButton; public ArrayList<Integer> getCheckedItemsPosition() { return checkedItemsPosition; } public String[] getSelectedFormsId() { String[] ids = new String[checkedItemsPosition.size()]; int i = 0; for(Integer pos : checkedItemsPosition) { Form f = forms.get(pos.intValue()); ids[i] = f.FormId; i++; } return ids; } /** * Called when selected forms has been downloaded and save it locally correctly. */ public void updateFormsNotDownloaded() { for (Integer pos : checkedItemsPosition) { remove(forms.get(pos.intValue())); } checkedItemsPosition.clear(); notifyDataSetChanged(); } public FormAdapter(Context context, int textViewResourceId, List<Form> objects, Button downloadButton) { super(context, textViewResourceId, objects); this.context = context; this.layoutResourceId = textViewResourceId; this.forms = objects; this.checkedItemsPosition = new ArrayList<Integer>(); this.downloadButton = downloadButton; } @Override public int getCount() { return forms.size(); } @Override public View getView(final int position, View convertView, ViewGroup parent) { Log.v("FormAdapter", "getView.postion: " + position); View row = convertView; if (row == null) { LayoutInflater inflater = ((Activity)context).getLayoutInflater(); row = inflater.inflate(layoutResourceId, parent, false); } Form f = forms.get(position); if (f != null) { CheckBox checkBox = (CheckBox)row.findViewById(R.id.itemCheckBox); if (checkBox != null) { checkBox.setText(f.Name); checkBox.setOnCheckedChangeListener(new OnCheckedChangeListener() { public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { //Form f = forms.get(position); if (isChecked) { //checkedItems.add(f.FormId); checkedItemsPosition.add(new Integer(position)); } else { //checkedItems.remove(checkedItems.indexOf(f.FormId)); checkedItemsPosition.remove(checkedItemsPosition.indexOf(new Integer(position))); } downloadButton.setEnabled(checkedItemsPosition.size() > 0); } }); } } return row; }}列表项是带有复选框的自定义项。在checkedItemsPosition上，我存储选中项目的位置。我的问题是在updateFormsNotDownloaded方法上。为什么我得到一个UnsupportedOperationException？ 最佳答案 我只能想到一个原因。您传递给ArrayAdapters构造函数的List 实现不支持remove（）。您可以使用ArrayList进行修复。如果由于某种原因您正在使用Arrays.asList（）从数组中构造列表，那么您将获得无法修改的列表。The size of the * {@code List} cannot be modified, i.e. adding and removing are unsupported