设置button为圆形

通过layler

   // 创建头像视图

    UIButton *logoButton = [[UIButton alloc] init];

    logoButton.frame = CGRectMake(50, 50, 100, 100);

    logoButton.layer.cornerRadius = 50;

    logoButton.backgroundColor = [UIColor redColor];

    [self.view addSubview:logoButton];

 以后完善