Java 如何从云Firestore获取数据数组?
这是我的密码:Java 如何从云Firestore获取数据数组?,java,android,firebase,google-cloud-firestore,Java,Android,Firebase,Google Cloud Firestore,这是我的密码: db.getFirestore().document("state/Madhya Pradesh/cities").get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() { @Override public void onComplete(@NonNull Task<DocumentSnapshot> task) {
db.getFirestore().document("state/Madhya Pradesh/cities").get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
DocumentSnapshot documentSnapshot=task.getResult();
}
});
db.getFirestore().document(“州/中央邦/城市”).get().addOnCompleteListener(新的OnCompleteListener()){
@凌驾
未完成的公共void(@NonNull任务){
DocumentSnapshot DocumentSnapshot=task.getResult();
}
});
要从firestore获取阵列,请执行以下操作:-
DocumentReference documentReference = firestore.collection("states").document(uid);
documentReference.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
@Override
public void onSuccess(DocumentSnapshot documentSnapshot){
if(documentSnapshot.exists()){
ArrayList<String> arrList = new ArrayList<String>();
arrList = (ArrayList) documentSnapshot.get("cities");
for(int i=0;i<arrList.size();i++){
//Traversing the list
}
}
}
DocumentReference=firestore.collection(“states”).document(uid);
documentReference.get().addOnSuccessListener(新的OnSuccessListener()){
@凌驾
成功时公共无效(文档快照文档快照){
if(documentSnapshot.exists()){
ArrayList arrList=新的ArrayList();
arrList=(ArrayList)documentSnapshot.get(“cities”);
对于(inti=0;i请检查下面的代码。希望它能帮助您
db.collection("Collection name").document("Document Id")
.collection("Collection name").get().addOnCompleteListener {
if (it.isSuccessful) {
if (it.result.isEmpty) {
//List is empty
} else {
val result = it.result.documents.map { it.toObject(YourModelClass::class.java)!! }
//Performe array list operation
// result is your array list
}
} else {
it.exception?.let {
//Print exception
}
}
}
请检查副本以了解如何从Cloud Firestore数据库获取阵列。