我想从数据库中检索数据。而在我在我将对DBAdapter,我用fetchAllBooks
方法得到一个光标:simpleCursorAdapter无法显示光标
public Cursor fetchAllBooks()
{
String selectQuery = "SELECT " + TABLE_TITLE + "." + KEY_TITLE_ID + " As _id, "
+ KEY_TITLE + ", " + KEY_PRICE + ", " + KEY_ISBN
+", GROUP_CONCAT(" + KEY_AUTHOR + ", ', ') AS authors"
+ " FROM " + TABLE_TITLE + " JOIN " + TABLE_AUTHOR
+ " USING (" + KEY_TITLE_ID + ")"
+ " GROUP BY " + KEY_TITLE_ID;
Cursor c = db.rawQuery(selectQuery, null);
return c;
}
在主要活动中,我使用fillData
方法来填充ListView控件:
private void fillData() {
Cursor c = db.fetchAllBooks();
startManagingCursor(c);
Log.d("count", c.getCount() + "");// could display the number of book. such as: count: 2; --- means cursor have 2 row(books)
if(c.moveToFirst()) {
do {
Log.d("title", BookContract.getTitle(c)); // could display the title of each book;
}while(c.moveToNext());
}
String[] from = new String[] {BookContract.KEY_TITLE, BookContract.KEY_AUTHORS};
int[] to = new int[] { R.id.cart_row_title, R.id.cart_row_author};
adapter = new SimpleCursorAdapter(this, R.layout.cart, c, from, to, 0);
setListAdapter(adapter);
}
正如你看到的,logcat的可以显示光标的内容。这意味着我成功地检索了游标。但是,listView无法显示书名和作者。我的代码中没有使用任何db.close()
或cursor.close()
。
的代表列表中的每个行项cart_row.xml
view.And含有一个列表视图中cart.xml
:
预先感谢。
定义'ListView控件无法显示them' – njzk2
@ njzk2你的意思是更换'setListAdapter(适配器)'和'ListView控件的ListView =(ListView控件)findViewById(android.R.id.list ); listView.setAdapter(适配器);'?但它仍然无法工作。 – sydridgm
没有。我请你定义你的意思。怎么了? (另外,你在哪里调用fillData,你的布局是什么样的,你有什么尝试?) – njzk2