如何在firebase android中获取value form键

FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference rootRef = database.getReference();

DatabaseReference keyRef = rootRef.child("key");

DatabaseReference keyRef = rootRef.child("key");
keyRef.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        // 获取键的值
        String value = dataSnapshot.getValue(String.class);
        // 在这里处理获取到的值
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        // 处理取消事件
    }
});