button 垂直分布

  UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];//button的类型
    button.frame = CGRectMake(100, 100,90, 90);//button的frame
   button.backgroundColor = [UIColor cyanColor];//button的背景颜色

//    [button setBackgroundImage:[UIImage imageNamed:@"man_64.png"] forState:UIControlStateNormal];

//    在UIButton中有三个对EdgeInsets的设置：ContentEdgeInsets、titleEdgeInsets、imageEdgeInsets
    [button setImage:[UIImage imageNamed:@"[e-mail]"] forState:UIControlStateNormal];//给button添加image
    button.imageEdgeInsets = UIEdgeInsetsMake(5,13,21,button.titleLabel.bounds.size.width);//设置image在button上的位置（上top，左left，下bottom，右right）这里可以写负值，对上写－5，那么image就象上移动5个像素

    [button setTitle:@"首页" forState:UIControlStateNormal];//设置button的title
    button.titleLabel.font = [UIFont systemFontOfSize:16];//title字体大小
    button.titleLabel.textAlignment = NSTextAlignmentCenter;//设置title的字体居中
    [button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];//设置title在一般情况下为白色字体
    [button setTitleColor:[UIColor grayColor] forState:UIControlStateHighlighted];//设置title在button被选中情况下为灰色字体
     button.titleEdgeInsets = UIEdgeInsetsMake(71, -button.titleLabel.bounds.size.width-50, 0, 0);//设置title在button上的位置（上top，左left，下bottom，右right）

//    [button setContentEdgeInsets:UIEdgeInsetsMake(70, 0, 0, 0)];//

//   button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter;//设置button的内容横向居中。。设置content是title和image一起变化

    [button addTarget:self action:@selector(tap) forControlEvents:UIControlEventTouchUpInside];