在iOS 7中实现heightForRowIndexPath：但是在iOS 8中使用编译时宏删除它 [英] Implement heightForRowIndexPath: in iOS 7, but remove it in iOS 8 using compile-time macro

问题描述

我想在iOS 8中实现新的自动调整大小表视图单元格，同时在iOS 7中保持对 heightForRowAtIndexPath：的支持。问题是我必须为iOS 8删除方法覆盖 heightForRowAtIndexPath：，但为iOS 7保留它。是否有一些编译时宏可以实现这一点？

I'd like to implement the new auto-resizing table view cells in iOS 8, while maintaining support for heightForRowAtIndexPath: in iOS 7. The problem is I have to remove the method override heightForRowAtIndexPath: for iOS 8, but keep in it for iOS 7. Is there some compile-time macro to use that will accomplish this?

推荐答案

您不能使用编译时宏，因为这是运行时决定。相反，你可以为iOS 8返回 UITableViewAutomaticDimension ，如果没有，则返回你计算的身高值。

You can not use a compile time macro because this is a run time decision. Instead, you can just return UITableViewAutomaticDimension for iOS 8 and if not, return your calculated height value.

#define IS_IOS_8_OR_LATER ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)

-(CGFloat) tableView: (UITableView * ) tableView heightForRowAtIndexPath: (NSIndexPath * ) indexPath {
  if (IS_IOS_8_OR_LATER)
    return UITableViewAutomaticDimension;
  else {
    //Your iOS 7 code here.
  }

}

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