改变UIButton上标题位置、文字颜色、背景色等

UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0, 100, 200, 100)];
  
  //添加点击事件
  [button addTarget:self action:@selector(pushToSecond) forControlEvents:UIControlEventTouchUpInside];
  
  //整个按钮的背景色（无背景图片时有效果）
  button.backgroundColor = [UIColor greenColor];
  
  //添加背景图片
  [button setBackgroundImage:[UIImage imageNamed:@"01.png"] forState:UIControlStateNormal];
  
  //按钮标题
  [button setTitle:@"Hello World!" forState:UIControlStateNormal];
  
  //button上子控件的水平对齐方式
  button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;
  
  //button上子控件的垂直对齐方式
  button.contentVerticalAlignment = UIControlContentVerticalAlignmentTop;
  
  //内容容器的偏移，让文字向右偏移20像素
  button.contentEdgeInsets = UIEdgeInsetsMake(0,20, 0, 0);
  
  //设置标题的背景颜色
  button.titleLabel.backgroundColor = [UIColor purpleColor];
  
  //标题颜色
  [button setTitleColor:[UIColor yellowColor]forState:UIControlStateNormal];
  
  button.imageView.contentMode = UIViewContentModeScaleAspectFit;
  
  [self.view addSubview:button];
  [button release];