java - 如何访问firebase数组

Question

如何在Android中访问指纹数组？我不知道该怎么办。

DatabaseReference dbTITO = FirebaseDatabase.getInstance().getReference("Employee/2/fingerprint");
dbTITO.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot)  {
        if (dataSnapshot.exists()) {
            byte[] imageFinger = dataSnapshot.child("fingerprint").getValue();

        } 
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
    }
});

enter image description here员工2代码:2部门名称:“刺客”指纹0:01:2482:1263:14:2005:426:227

Answer 1

只要您使用像 Employee/2/fingerprint 这样的引用，就无需再次调用 child("fingerprint")。要解决此问题，请使用以下代码行:

DatabaseReference fingerprintRef = rootRef.child("Employee").child("2").child("fingerprint");
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        long count = dataSnapshot.getChildrenCount();
        byte[] bytes = new byte[(int) count];
        int count = 0;
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            long value = ds.getValue(Long.class);
            bytes[count] = (byte) value;
            count++;
        }

        //Do what you need to do with your array
    }

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