如何主动获取firebase到android的数据

Question

I don't want to automatically receive data from firebase on change but receive it only when pressing a button. Any ideas on how to adapt the code below?

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        name = (EditText) findViewById(R.id.editTextTextPersonName);
        butt = (Button) findViewById(R.id.button);
        viet = (TextView) findViewById(R.id.textView_viet);
        butt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String var = name.getText().toString();
                getdataUser();
            }
        });
        }
    private void getdataUser(){
        data_user1.child(var).addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot data) {
                String yy = data.getValue().toString();
                viet.setText(yy)
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });
    }

Any ideas are appreciated!

Answer 1

If you want to read data a single time and be done with that, you shouldn't use addValueEventListener() . Instead use addListenerForSingleValueEvent() as described in the documentation . You still have to process the results asynchronous in a callback, but it will be invoked only once with the snapshot of data at the location of your query.

If you are trying to query the database synchronously to return the data immediately, there is no API for that - you have to process the data asynchronously with a callback.