改变Button内text相对位置的颜色和字体大小

（抱歉没备注，有问题可以私信）

// 创建一个普通Button

CGRect rect = [UIScreen mainScreen].bounds;

UIButton * teamBt = [UIButton buttonWithType:UIButtonTypeSystem];

teamBt.frame = CGRectMake(rect.size.width/2 - rect.size.width/320 *90,  30,  rect.size.width/320 *180, 20);

teamBt.titleLabel.font =  [UIFont fontWithName:@"Helvetica-Bold" size:20];

[teamBt addTarget:self action:@selector(thisIsAButton) forControlEvents:UIControlEventTouchUpInside];

//设置按钮居中

[teamBt setContentHorizontalAlignment:UIControlContentHorizontalAlignmentCenter];

// 只改动后两个字的颜色

NSString *title = [NSString stringWithFormat:@"%@简介",self.teamName];

NSInteger num = title.length -2;

NSMutableAttributedString *str = [[NSMutableAttributedString alloc] initWithString:title];

[str addAttribute:NSForegroundColorAttributeName value:[UIColor whiteColor] range:NSMakeRange(0,num)];

[str addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:64.0/255 green:154.0/255 blue:156.0/255 alpha:1] range:NSMakeRange(num,2)];

[str addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"Helvetica-Bold" size:20] range:NSMakeRange(num, 2)];

[teamBt setAttributedTitle:str forState:UIControlStateNormal];

[self.view addSubview:teamBt];