Future Method Has No Data

Question

我有一个从mysql数据库获取数据的未来方法。我正在使用FutureBuilder，如果快照没有数据返回循环进度，否则我的ui。但我只看到了循环发展。这是我未来的方法。

Future _getData() async {
Mysql db = Mysql();
db.getConnection().then((conn) async {
debugPrint('User ID: $uid');
var correctStats =
await conn.query('select correctCount from users where uid = "$uid"');
for (var row in correctStats) {
correctCountStats = row[0];
}
var wrongStats =
await conn.query('select wrongCount from users where uid = "$uid"');
for (var row in wrongStats) {
wrongCountStats = row[0];
}
});
}

Answer 1

您没有返回数据库。你可以做我更喜欢使用await

Future _getData() async {
Mysql db = Mysql();
final conn = await db.getConnection();
debugPrint('User ID: $uid');
var correctStats =
await conn.query('select correctCount from users where uid = "$uid"');
for (var row in correctStats) {
correctCountStats = row[0];
}
var wrongStats =
await conn.query('select wrongCount from users where uid = "$uid"');
for (var row in wrongStats) {
wrongCountStats = row[0];
}
return db;
}