iOS8之后，主要使用UIAlertController进行信息的显示，而默认的样式使用的比较多，所以封装了一个，以方便以后使用。
调用以下函数即可，参数需要自己设置：
-(void)showIntroDuction:(NSString *)title :(NSString *)showText :(NSString *)btnStr :(UIFont *)titleFont :(UIFont *) showTextFont :(UIColor *) titleColor :(UIColor *)showTextColor :(UIColor *)btnColor
{
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:title message:showText preferredStyle:UIAlertControllerStyleAlert];
// 设置标题的字体
NSMutableAttributedString *attributedStrTitle = [[NSMutableAttributedString alloc]initWithString:title];
[attributedStrTitle addAttribute:NSFontAttributeName value:titleFont range:NSMakeRange(0, [title length])];
[attributedStrTitle addAttribute:NSForegroundColorAttributeName value:titleColor range:NSMakeRange(0, [title length])];
// 利用KVC赋值
[alertController setValue:attributedStrTitle forKey:@"attributedTitle"];
// 设置正文的字体
NSMutableAttributedString *messageAtt = [[NSMutableAttributedString alloc] initWithString:showText];
[messageAtt addAttribute:NSFontAttributeName value:showTextFont range:NSMakeRange(0, [showText length])];
[messageAtt addAttribute:NSForegroundColorAttributeName value:showTextColor range:NSMakeRange(0, [showText length])];
[alertController setValue:messageAtt forKey:@"attributedMessage"];
// 按钮
UIAlertAction *alertAction = [UIAlertAction actionWithTitle:btnStr style:UIAlertActionStyleDefault handler:nil];
[alertController addAction:alertAction];
// 按钮颜色
[alertAction setValue:btnColor forKey:@"_titleTextColor"];
[self presentViewController:alertController animated:YES completion:nil];
}
