android - 我如何在游标中使用子字符串？

Question

我有一个 Cursor Select from sqlite，在这个 query 中我做了一个 substring 但我可以'y 使用 substring 它不会给我任何错误，但会显示 listView 为空。

    try {
        String value = editText.getText().toString();
        cursor = sql.rawQuery(
                "SELECT MetaDataID,Data,CategoryID,ParentID FROM Book WHERE Data LIKE '"
                        + "%" + value + "%'", null);
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                do {
                    Struct_Search note = new Struct_Search();
                    note.MetaData = cursor.getInt(cursor.getColumnIndex("MetaDataID"));
                    Result = cursor.getString(cursor.getColumnIndex("Data"));
                    int A = Result.indexOf(value);
                    String V = Result.substring(A,100);
                    note.Value = V;
                    note.NumberAyeh = cursor.getInt(cursor.getColumnIndex("CategoryID"));
                    ParentID = cursor.getInt(cursor.getColumnIndex("ParentID"));
                    CursorSecond = sql.rawQuery("SELECT name FROM ContentList WHERE id ="+ ParentID, null);
                    if (CursorSecond != null) {
                        do {
                            CursorSecond.moveToFirst();
                            note.NameSureh = CursorSecond.getString(CursorSecond.getColumnIndex("name"));
                            CursorSecond.close();
                        } while (CursorSecond.moveToNext());
                    }
                    notes.add(note);
                } while (cursor.moveToNext());
            }
            adapter.notifyDataSetChanged();
        }
    } catch (Exception e) {
    } finally {
        cursor.close();
    }

注意:此行无效:

                String V = Result.substring(A,100);
                note.Value = V;

Answer 1

如果您尝试获取字符索引后的前 100 个字符，并为其设置 note.Value，请将您的子字符串更改为

 // substring(int beginIndex, int endIndex)
 Result.substring(A, A + 100);

在java中，substring的第二个参数是endIndex，不是Length。