Flutter DocumentSnapshot [英] Flutter DocumentSnapshot
问题描述
我正在尝试从firebase的DocumentSnapshot中获取数据。
I am trying to get the data from a DocumentSnapshot from firebase.
Firestore.instance.collection('products').document("Lucius_Malfoys_Zauberstab").get().then((DocumentSnapshot ds) {
print(ds.exists);
});
此方法可以正常工作并返回true,但是:
This method works totally fine and returns true, but:
var keys = ["Lucius_Malfoys_Zauberstab"];
String id = keys[0];
print(id); ---> prints Lucius_Malfoys_Zauberstab
Firestore.instance.collection('products').document(id).get().then((DocumentSnapshot ds) {
print(ds.exists);
});
返回假...
有任何人都有一个主意,为什么会这样呢?
这只是我的应用程序中的一个小问题,但是我很好奇为什么会这样。只是为了理解。谢谢!
Does anyone have an idea, why this is the case? It is just a small problem in my application, but I am curious why this happens. Just for understanding. Thank you!
编辑:
这是购物车集合的屏幕截图:
Here is a screenshot of the cart collection:
以下是产品的屏幕截图集合:
Here is a screenshot of the products collection:
推荐答案
我无法重现该问题。此时,我能做的最好的事情就是向您展示我的工作:
I can't reproduce the problem. The best I can do at this point is show you what I've done:
false
的第一次打印是在获得文档之前。然后,我创建了文档,再次运行 _test
,并打印了 true
。
The first print of false
is before I had the document. I then created the document, ran _test
again, and it printed true
.
如果我取消对 / 55652643 / {document}
的许可,则 print
语句为'达到了t,相反,我得到了堆栈跟踪,表明该权限已被拒绝。
If I remove my permission on /55652643/{document}
, the print
statement isn't reached, and instead I get a stack trace that permission has been denied.
这篇关于Flutter DocumentSnapshot的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!