テキストの設定方法UIButton
topYellowButton2 = [UIButton buttonWithType:UIButtonTypeCustom];
topYellowButton2.frame = CGRectMake(80, 0, 90, 20);
[topYellowButton2 setTitleColor:[UIColor colorWithRed:0.0 green:0.6 blue:1.0 alpha:1.0] forState:UIControlStateNormal];