Cannot drag a button using Robotium

I try to drag a button using following line of code but nothing happens. I am beginner on Robotium so it is possible that I miss something. Can you help please?

public void testGesture(){

float fromX = 434.0f;

float toX = 636.0f;

float fromY = 1016.0f;

float toY = 1016.0f;

int stepCount = 5;

solo.sleep(2000);

solo.drag(fromX, toX, fromY, toY, stepCount);

}