如何从 firebase 实时数据库中检索两个不同的值并在 onDataChange 方法之外使用？

Question

   int percentint=(vdcostint/b1txtaint)*100;

-------vdcostint is a value retrieved from firebase and b1txtaint is another value from different key---

But I am unable to use two values outside onDataChange.

Answer 1

The values you obtain inside onDataChange() are not available outside the method. To use the data outside those values you need to call a function from inside of the onDataChange() and do the calculations there.