wilddogteam / demo-ios-drawing Goto Github PK

由于你们单次拉取数据有限制，想请教一个分页拉取数据的方案

I want to delete all datas under root node,here is my code:

- (void)clearDatas {
    __weak __typeof(self) weakSelf;
     [[[self.wilddog queryOrderedByKey] queryLimitedToFirst:5] observeEventType:WDGDataEventTypeValue withBlock:^(WDGDataSnapshot *snapshot) {
         NSLog(@"%@",snapshot.value);
         NSEnumerator *children = snapshot.children;
         WDGDataSnapshot *next = children.nextObject;
         while (next) {
            [next.ref removeValue];
             next = children.nextObject;
         }
    }];
}

This is a button event,I want to delete 5 pieces of data every time I click the button.But the problem is,when I first click the button,the snapshot returned contains 5 pieces of data,and I can delete them correctly.
But after the first time,the snapshot returned contains no data,the console shows:

2017-03-09 11:57:17.901947 Wilddog Drawing[5475:2673406] Not a valid path: / -> (null)
2017-03-09 11:57:17.902140 Wilddog Drawing[5475:2673406] (null)

So,there are two questions:
1 how to return correct data after first click.
2 I think deleting datas in this way is not elegant,is there a more convenient way to delete data under the root node?

The method is
self.childAddedHandle = [self.wilddog observeEventType:WDGDataEventTypeChildAdded withBlock:^(WDGDataSnapshot *snapshot) {...}];
When the the requested data is too big,the block won't be called.And the console show the following message:
"too_big, error reason:Data requested exceeds the maximum size that can be accessed with a single request
Data requested exceeds the maximum size that can be accessed with a single request."

In this case,what should I do to get the data?