Question

我输入新数据后，我的ListView将无法刷新。它只会在我更改标签时刷新。我输入了notifyDataSetChange()但它仍然无效。救命啊！

public class Tab4 extends Fragment {

TextView title;
TextView DateTitle;
TextView AmountTitle;
TextView DescTitle;
ListView ExpensesList;
List<Expenses> Expenses;
Expenses expenses;
ExpensesListAdapter adapter;
Toast mToast;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    // TODO Auto-generated method stub

    View rootView = inflater.inflate(R.layout.tab4, container, false);

    title = (TextView) rootView.findViewById(R.id.Title);
    DateTitle = (TextView) rootView.findViewById(R.id.DateTitle);
    AmountTitle = (TextView) rootView.findViewById(R.id.AmountTitle);
    DescTitle = (TextView) rootView.findViewById(R.id.DescTitle);
    ExpensesList = (ListView) rootView.findViewById(R.id.ExpensesList);

    Expenses = new ArrayList<Expenses>();
    expenses = new Expenses();
    mToast = Toast.makeText(getActivity().getApplicationContext(), "",
            Toast.LENGTH_SHORT);
    ExpensesList.setAdapter(adapter);
    adapter = new ExpensesListAdapter(
            getActivity().getApplicationContext(), Expenses);

    if (expenses.getAllExpenses().size() == 0) {
        title.setText("Total number of record is 0");
        DateTitle.setVisibility(View.GONE);
        AmountTitle.setVisibility(View.GONE);
        DescTitle.setVisibility(View.GONE);
    } else {
        for (int i = 0; i < expenses.getAllExpenses().size(); i++) {
            Expenses.add(expenses.getAllExpenses().get(i));
            System.out.println("Expenses are "
                    + expenses.getAllExpenses().get(i));

            adapter.notifyDataSetChanged();
            ExpensesList.invalidateViews();
        }
        title.setText("Total number of record is "
                + expenses.getAllExpenses().size());
    }

    ExpensesList.setOnItemLongClickListener(new OnItemLongClickListener() {

        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view,
                final int position, long id) {
            // TODO Auto-generated method stub
            AlertDialog.Builder builder = new AlertDialog.Builder(
                    getActivity());
            builder.setMessage("ARE YOU SURE YOU WANT TO DELETE THIS RECORD?");
            builder.setCancelable(false);
            builder.setPositiveButton("Yes",
                    new DialogInterface.OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog,
                                int which) {
                            // TODO Auto-generated method stub
                            expenses = new Expenses();
                            expenses = expenses.getAllExpenses().get(
                                    position);
                            expenses.delete();
                            Expenses.remove(position);
                            adapter.notifyDataSetChanged();


                            title.setText("Total number of record is "
                                    + expenses.getAllExpenses().size());

                            mToast.setText("Record has been deleted");
                            mToast.show();
                        }
                    });

            builder.setNegativeButton("No",
                    new DialogInterface.OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog,
                                int which) {
                            // TODO Auto-generated method stub
                            dialog.dismiss();
                        }
                    });

            builder.show();
            return false;
        }
    });

    return rootView;
}
}

class ExpensesListAdapter extends BaseAdapter {

List<Expenses> Expenses;
Context context;
LayoutInflater inflater;

public ExpensesListAdapter(Context context, List<Expenses> Expenses) {
    this.context = context;
    this.Expenses = Expenses;

    inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return Expenses.size();
}

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return position;
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return position;
}

public class Holder {
    TextView Date;
    TextView Amount;
    TextView Desc;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub

    Holder holder = new Holder();
    convertView = inflater.inflate(R.layout.listview_expenseslist, null);

    holder.Date = (TextView) convertView.findViewById(R.id.ExpensesDate);
    holder.Amount = (TextView) convertView
            .findViewById(R.id.ExpensesAmount);
    holder.Desc = (TextView) convertView.findViewById(R.id.ExpensesDesc);

    holder.Date.setText(Expenses.get(position).Date);
    holder.Amount.setText(String.valueOf(Expenses.get(position).Amount));
    holder.Desc.setText(Expenses.get(position).Desc);

    return convertView;
}

}

Answer 1

我输入新数据后，我的列表视图不会刷新。它只会如果我改变标签，请刷新。

因为当前在Expenses ArrayList中添加了新数据。

要更新ListView Adapter中的新项目，需要在data-sorcude中添加项目，该项目在适配器内用于获取数据和getCount`方法。

要实现同样的目的，请在ExpensesListAdapter中创建一个方法：

public void addAllItem(List<Expenses> strItem){
  this.Expenses.addAll(strItem);
  this.notifyDataSetChanged(); 
}

现在，在addNewItem点击正面按钮时，调用AlertDialog方法添加新项目：

 adapter.addNewItem(expenses.getAllExpenses());

我的列表视图不会以片段形式更新

1 个答案: