如何将 Firebase 数据存储在数组中并打印出来？

Question

我整天都在尝试将 firebase 数据存储到一个数组中并打印出来，但无济于事。我将非常感谢社区的帮助。

下图是当前 firebase 数据库的样子：

下面是从 firebase 读取数据的函数代码：

- (void)readDataFromServer {

_ref = [[FIRDatabase database] reference];

_hotelRef = [_ref child:@"hotel bookings"];

NSString *userID = [FIRAuth auth].currentUser.uid;

FIRDatabaseQuery *userHotelBookingsQuery = [[_hotelRef child:userID] queryOrderedByChild:@"number"];

[userHotelBookingsQuery observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot * _Nonnull snapshot) {

    if (snapshot.value == [NSNull null]) {

        NSLog(@"No messages");

    } else {

    [self.arrayOfBookingDetail removeAllObjects];

    self.arrayOfBookingDetail = (snapshot.value);

    NSString *firstMessage = [self.arrayOfBookingDetail objectAtIndex:0];

    NSLog(@"First message is: %@", firstMessage);

    }


 }];

}

Answer 1

您的代码失败，因为您从用户 uid 获得了 child，但实际上并不存在。 K2xxxxxxxx 是每个元素的唯一字符串，不对应于用户 ID。试试这个

_ref = [[FIRDatabase database] reference];

_hotelRef = [_ref child:@"hotel bookings"];

FIRDatabaseQuery *userHotelBookingsQuery = [_hotelRef queryOrderedByChild:@"number"];

[userHotelBookingsQuery observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot * _Nonnull snapshot) {

    if (snapshot.value == [NSNull null]) {
        NSLog(@"No messages");
    } else {
      //[self.arrayOfBookingDetail removeAllObjects];
      //self.arrayOfBookingDetail = (snapshot.children);
      //NSString *firstMessage = [self.arrayOfBookingDetail objectAtIndex:0];
      //NSLog(@"First message is: %@", firstMessage);
      NSDictionary *allUsersData = (NSDictionary*)snapshot.value;
      for (NSString *key in allUsersData.allKeys) {
           NSLog("@key is %@, data is %@",key,allUsersData[key]);
      }
    }

 }];

}

编辑：

要查询 特定用户 - 将您的查询更改为

 FIRDatabaseQuery *userHotelBookingsQuery = [[_hotelRef queryOrderedByChild:@"userID"] queryEqualToValue:@"GEmxxxxxxxxx"];

如何将 Firebase 数据存储在数组中并打印出来？

How to store Firebase data in array and print them out?

ios

firebase

firebase-realtime-database