Your color isn't correct. If you step into the drawRect function you can see the f,f1,f2,f3 variables which hold the rgba values for the color. f3 is the alpha value, and (0x800000 >> 24 & 255) / 255.0F is 0.0f, so your alpha is 0, which means it is transparent. Try a bigger value
1342177280 is a gray color, for instance.