//给某个按钮上的数字设置大小

+ (void)setDefaultFont:(id)sender size:(float)size{

    [sender setFont:[UIFont fontWithName:@"Helvetica" size:size]];

}

用法:

-(void)initButton

{

    UIButton *rightButton = [[UIButton alloc] initWithFrame:CGRectMake(50, 100, 100, 50)];

    [rightButton setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];

    rightButton.backgroundColor=[UIColor redColor];

    //给按钮上的字设置大小

    [Utils setDefaultFont:rightButton size:20];

    [rightButton setTitle:@"完成" forState:UIControlStateNormal];

    [self.view addSubview:rightButton];

}