[英]Exception when ordering query by nested data with Firebase Android API
According to the Firebase documentation, it should be possible to order a query by a deeply nested child by passing the full path to the orderByChild()
method like this 根据Firebase文档,应该可以通过将完整路径传递给
orderByChild()
方法来对深度嵌套的子项进行查询排序
Firebase ref = new Firebase("https://dinosaur-facts.firebaseio.com/dinosaurs");
Query queryRef = ref.orderByChild("dimensions/height");
queryRef.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot snapshot, String previousChild) {
DinosaurFacts facts = snapshot.getValue(DinosaurFacts.class);
System.out.println(snapshot.getKey() + " was " + facts.getHeight() + " meters tall");
}
});
But calling orderByChild("dinosaurs/height")
throws a FirebaseException
with the message Invalid key: dinosaurs/height. Keys must not contain '/', '.', '#', '$', '[', or ']'
但是,调用
orderByChild("dinosaurs/height")
会引发FirebaseException
,并显示消息Invalid key: dinosaurs/height. Keys must not contain '/', '.', '#', '$', '[', or ']'
Invalid key: dinosaurs/height. Keys must not contain '/', '.', '#', '$', '[', or ']'
. Invalid key: dinosaurs/height. Keys must not contain '/', '.', '#', '$', '[', or ']'
。
Indeed, the key is rejected by the following firebase method 实际上,该密钥被以下firebase方法拒绝
private static final Pattern INVALID_KEY_REGEX = Pattern.compile("[\\[\\]\\.#\\$\\/\\u0000-\\u001F\\u007F]");
private static boolean isValidKey(String key) {
return key.equals(".info") || !INVALID_KEY_REGEX.matcher(key).find();
}
What is the correct way of querying using the full path of an object? 使用对象的完整路径进行查询的正确方法是什么?
The ability to order by a nested child was added in version 2.4 of the Firebase SDK for Java . Firebase SDK for Java 2.4版中增加了通过嵌套子项进行订购的功能。
I just tried using a /
on an older version of the SDK, and get the same error as you have. 我只是尝试在旧版SDK上使用
/
,并得到与您相同的错误。 So my best bet is that you forgot to update your project to use Firebase SDK version 2.4. 因此,我最好的选择是,您忘记了更新项目以使用Firebase SDK 2.4版。
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