// 初始化按钮
  UIButton *button = [[UIButton alloc] init];
  // 设置尺寸
  button.frame = CGRectMake(100, 200, 200, 50);
  
  // 加载图片
  UIImage *image = [UIImage imageNamed:@"ppm_new_shuliang.png"];
  
  // 设置背景图片
  [button setBackgroundImage:image forState:UIControlStateNormal];
  
  // 添加按钮 
  [self.view addSubview:button];

  // 初始化按钮
  UIButton *button = [[UIButton alloc] init];
  // 设置尺寸
  button.frame = CGRectMake(100, 200, 200, 50);
  
  CGFloat top = 0; // 顶端盖高度
  CGFloat bottom = 0 ; // 底端盖高度
  CGFloat left = 22; // 左端盖宽度
  CGFloat right = 22; // 右端盖宽度
  UIEdgeInsets insets = UIEdgeInsetsMake(top, left, bottom, right);
  
  
  // 加载图片
  UIImage *image = [UIImage imageNamed:@"ppm_new_shuliang.png"];
  
  image = [image resizableImageWithCapInsets:insets resizingMode:UIImageResizingModeStretch];
  
  // 设置背景图片
  [button setBackgroundImage:image forState:UIControlStateNormal];
  
  // 添加按钮 
  [self.view addSubview:button];