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[英]How to access a particular field of other document which is in some "abc" Collection from some other "xyz" Collection in Firestore Flutter?
[英]How can I store document field data from a particular collection in firestore database to a string variable in kotlin
我想從 Cloud Firestore 獲取數據,並且必須將其存儲到字符串變量中,但無法這樣做並且需要幫助。
這是下面的代碼
val db = FirebaseFirestore.getInstance()
val docRef = db.collection("SlideShowImages").document("1")
docRef.get()
.addOnSuccessListener { document ->
if (document != null) {
Log.d(TAG, "DocumentSnapshot data: ${document.data}")
} else {
Log.d(TAG, "No such document")
}
}
.addOnFailureListener { exception ->
Log.d(TAG, "get failed with ", exception)
}
從數據庫中獲取它,我希望Link存儲到變量 first_image
{about=FCB, link=https://firebasestorage.googleapis.com/v0/b/missionx-g6305.appspot.com/o/EVENTS%2FSlide%20Show%20Images%2FCurrent%2FFCB.jpg?alt=media&token=950c5200-c553-4639-b33e-2b91a220b19c}
我想將它存儲在變量中
val first_image : String
first_image = document.data.link
當我使用它時出現錯誤
並放置變量類型var
以便您可以修改值。 Val
只允許為該變量設置永久值。
private var first_image: String
並在您的變量中獲取圖像:
first_image = document.getString("link");
閱讀val 和 var之間的區別。
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