检查用户是否存在于 Firestore [英] Check if user exists in Firestore
问题描述
我想在 Cloud Firestore 中创建一个用户数据库,将电子邮件作为每个用户的唯一 ID.用户应该在一个collection
中,每个用户就是一个document
.
I'd like to create a users database in Cloud Firestore, with the email as the unique ID for each user. The users should be in a collection
, and each user is a document
.
这是我检查用户是否存在于登录活动中的方法:
This is how I check if the user exists in the login activity:
FirebaseFirestore db = FirebaseFirestore.getInstance();
final DocumentReference userRef = db.collection("users").document(email);
userRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
Toast.makeText(LoginActivity.this, task.getResult().toString(),
Toast.LENGTH_SHORT).show();
if (document != null) {
//The user exists...
}
else {
//The user doesn't exist...
}
}
}
else
connectionErrorActivity();
}
});
数据库是空的,如你所见:
The database is empty, as you can see:
我的问题是,document
永远不会为空,即使数据库是空的. toast
显示 的字符串值code>document
是:COM.GOOGLE.FIREBASE.FIRESTORE.DOCUMENTSNAPSHOT@8ED6B96
.
My problem is, that document
is never null, even tough the database is empty. The toast
shows that the string value of document
is: COM.GOOGLE.FIREBASE.FIRESTORE.DOCUMENTSNAPSHOT@8ED6B96
.
这是正确的方法吗?我能做些什么来修复它?
Is this the correct way to do this? What can I do to fix it?
推荐答案
这个 Task
的结果是一个 DocumentSnapshot
.通过 存在
方法.
The result of this Task
is a DocumentSnapshot
. Whether or not the underlying document actually exists is available via the exists
method.
如果文档确实存在,您可以调用 getData
来获取它的内容.
If the document does exist you can call getData
to get at the contents of it.
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