Question

我正在尝试从api中读取数据，在数据库中填充该数据并在列表视图中显示它。我继续超出索引限制，但我不知道为什么。 Book是带有sting phoneNo和字符串名称的简单书类。我能够检索数据。当我打印我获取的数据时，我得到正确的输出，但当我尝试在数据库中插入数据并获取它时，我仍然遇到问题。

            List<Book> list = db.getAllBooks();
            for(int i = 0; i<4; i++) {
                thatName[i] = list.get(i).getName();
                thatMobile[i] = list.get(i).getPhoneNo();
                Log.d("List 1", thatName[i]);
                Log.d("List 2", thatMobile[i]);
            }

            customListViewAdapter = new CustomListViewAdapter(getApplication(),thatName,thatMobile);

            listView.setAdapter(customListViewAdapter);
    };

}

DB

 public List<Book> getAllBooks() {
    List<Book> books = new LinkedList<Book>();

    // 1. build the query
    String query = "SELECT  * FROM " + TABLE_BOOKS;

    // 2. get reference to writable DB
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(query, null);

    // 3. go over each row, build book and add it to list
    Book book = null;
    if (cursor.moveToFirst()) {
        do {
            book = new Book();
            book.setPhoneNo(cursor.getString(1));
            book.setName(cursor.getString(0));
            //book.setAuthor(cursor.getString(2));

            // Add book to books
            books.add(book);
        } while (cursor.moveToNext());
    }

    Log.d("getAllBooks()", books.toString());

    // return books
    return books;
}

Answer 1

您正在指定您将迭代的四个项目：

for(int i = 0; i<4; i++) {
    thatName[i] = list.get(i).getName();
    thatMobile[i] = list.get(i).getPhoneNo();
    Log.d("List 1", thatName[i]);
    Log.d("List 2", thatMobile[i]);
}

IndexOutOfBoundsException表示您尝试通过大于列表中最大索引的索引从列表中检索项目。相反，您可以尝试找出列表中的项目数：

for(int i = 0; i < list.size(); i++)

或只是遍历列表本身：

for(Book book: list)

索引超出了android

1 个答案: