while (cursor.moveToNext()) 在 android studio 中只运行一次

Question

我想在单击每个日期时显示不同的文本，我检查了日志，似乎当我单击一次后语句不起作用..有什么想法吗？

这是我的代码

     calendar.setOnDateChangeListener(new CalendarView.OnDateChangeListener() {
            @Override
            public void onSelectedDayChange(@NonNull CalendarView calendarView, int year, int month, int dayOfMonth) {
                tapDate = year + "/" + (month + 1) + "/" + dayOfMonth;
                selectedDate.setText(tapDate);
                Log.d(TAG, "onSelectedDayChange: tapDate"+ tapDate);

                while (cursor.moveToNext()) {
                    item = new Shelf_items();
                    item.setBookTitle(cursor.getString(0));
                    item.setWriteDate(cursor.getString(1));
                    Log.d(TAG, "onSelectedDayChange: while runs");

                    if(item.getWriteDate().equals(tapDate)){
                        mShelf.add(item);
                        Log.d(TAG, "onSelectedDayChange: mshelf item"+item);

                        for(Shelf_items i: mShelf){
                            i_result = i.getBookTitle() + " / ";
                        }
                        f_result +=i_result;
                        Log.d(TAG, "onSelectedDayChange: for 문: "+i_result);
                    }
                    bookName.setText(f_result);
                }
                cursor.close();
                
            }

        });

Answer 1

如果要再次循环游标结果集，则需要将游标倒回到开头。替换

while (cursor.moveToNext()) {
    ...
}

与

if (cursor.moveToFirst()) {
    do {
        ...
    } while (cursor.moveToNext());
}

并删除 cursor.close()，因为您的光标尚未完成。