【代码札记】按钮带下划线的写法

- (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view.        //初始化按钮    [self initRegisterButton];}#pragma -mark -funcitons-(void)initRegisterButton{    //注册账号按钮    UIButton *registerButton=[UIButton buttonWithType:UIButtonTypeRoundedRect];    registerButton.frame=CGRectMake(50,100, 100, 20);    registerButton.backgroundColor=[UIColor clearColor];    [registerButton setTitle:@"注册账号" forState:UIControlStateNormal];    [registerButton addTarget:self action:@selector(doClickRegisterButton:) forControlEvents:UIControlEventTouchUpInside];    registerButton.titleLabel.textColor=[UIColor colorWithRed:144.0/255.0 green:144.0/255.0 blue:144.0/255.0 alpha:0.8];    [self.view addSubview:registerButton];            //注册账号下的线    UIImageView *line=[[UIImageView alloc]initWithFrame:CGRectMake(registerButton.frame.origin.x+10, registerButton.frame.origin.y+registerButton.frame.size.height, 100, 1)];    line.backgroundColor=[UIColor colorWithRed:144.0/255.0 green:144.0/255.0 blue:144.0/255.0 alpha:0.3];    [self.view addSubview:line];}#pragma -mark -doClickButton-(void)doClickRegisterButton:(UIButton *)btn{    NSLog(@"--doClickRegisterButton--");}