关于设置 UIPopoverController.popoverContentSize 大小的坑

在 IOS 8 中，这样设置是没有问题的，但是在 IOS 7 中，这样的设置就会出现问题了，无论你怎样设置，popover  出来的内容框大小依然是默认的大小。

_popoverController = [[UIPopoverController alloc] initWithContentViewController:_contentViewController];

    _popoverController.delegate = self;

    _contentViewController.preferredContentSize = _contentViewController.view.bounds.size;

    [_popoverController presentPopoverFromRect:position inView:view permittedArrowDirections:UIPopoverArrowDirectionUp | UIPopoverArrowDirectionDown animated:YES];

查了一下资料，在 IOS 7 中需要把

_contentViewController.preferredContentSize = _contentViewController.view.bounds.size;

提前到

_popoverController = [[UIPopoverController alloc] initWithContentViewController:_contentViewController];

之前。这样，设置 popover 的大小就能成功生效。

关于 popoverContentSize 大小的问题，stackoverflow 的参考如下：

Take two steps to solve this

Step One:

As an immediate fix, you can set preferredContentSize property of UIViewController

[popoverViewController setPreferredContentSize:CGSizeMake(248.0,216.0)]; 

before initalizing UIPopoverController

UIPopoverController *popoverController = [[UIPopoverController alloc]initWithContentViewController:popoverViewController];

Step Two:

In iOS8, UIPopoverPresentationController is getting introduced as a replacement of UIPopoverController

if ([popoverViewController respondsToSelector:@selector(popoverPresentationController)]) {
   popoverViewController.modalPresentationStyle = UIModalPresentationPopover;
   [popoverViewController setPreferredContentSize:CGSizeMake(248.0,216.0)];

   UIPopoverPresentationController *popoverPresentation = popoverViewController.popoverPresentationController;
   [popoverPresentation setSourceView:_sourceView];
   [popoverPresentation setSourceRect:_sourceRect];
   [popoverPresentation setPermittedArrowDirections:UIPopoverArrowDirectionUp];

   [self presentViewController:popoverViewController animated:YES completion:nil];
} else {
   //existing code...
}

As of now, pre-release documentation is available for further reference.

参考链接：http://stackoverflow.com/questions/24772933/popovercontentsize-not-responding-in-ios-8

原文：http://blog.csdn.net/chaoyuan899/article/details/44621863