I'm building a Brain Trainer app but I'm not showing my TEXTVIEW when I'm running my app and the warning shows that it does not concatenate displaying text with setText

sumTextView.setText(Integer.toString(a) + " + " + Integer.toString(b));

This Line show warning you see in pic..

Use String.format();

sumTextView.setText(String.format("%1$d + %2$d", a, b));

With this you can format a string correctly with multiple variables, no matter whether they are strings or integers. This example takes the value of variable a and replaces the placeholder %1$d with it. Same goes for the other variable.