在Firebase中获取子名称 [英] Get child names in Firebase

问题描述

{
  "items" : {
    "Chemistry" : {
      "-KiUOPW8TR_QcEeDbrAy" : {
        "answer" : "ssssss",
        "id" : "1",
        "question" : "sss"
      }
    },
    "Countries" : {
      "-KiUR2ilBYN5LJU6uOCf" : {
        "answer" : "ffffff",
        "id" : "1",
        "question" : "fffff"
      }
    },
    "Film" : {
      "-KiUOr7GbPhV_perbHt4" : {
        "answer" : "dddd",
        "id" : "1",
        "question" : "dd"
      }
    }
}

从以上数据中，我仅想获取项目的子名称.

From the above data, I want to get only child names of items.

例如.我想得到这些名字

Eg. I want to get these names

Chemistry 
Countries 
Film

我该怎么办?

推荐答案

要获取这些名称，请使用以下代码:

To get those names, please use this code:

DatabaseReference itemsRef = FirebaseDatabase.getInstance().getReference().child("items");
ValueEventListener eventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String name = ds.getKey();  
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        Log.d("TAG", databaseError.getMessage()); //Don't ignore potential errors!
    }
};
itemsRef.addListenerForSingleValueEvent(eventListener);

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