Maximum height of iOS 8 Today Extension?

问题

I am working on a Today Extension with a dynamically sized table. I have been able to get the table to resize for the content using:

    self.preferredContentSize = accountsTable.contentSize

However, I have found that it will not get taller than a certain size (568 px) even though I can tell the table contentSize is larger.

I'm not clear if this is a built-in limit or if there is a way around this to make a larger view. It appears that some previous extensions (Stocks widget) is able to become larger.

Anyone else running into the same behavior. Anyone know if it's possible to make an extension appear larger either immediately or using a "Show All" button like the Stock widget?

回答1:

I made some tests and you can calculate the maximum height of your Today Extension with this formular:

for iPhone:

float maxHeight = [[ UIScreen mainScreen ] bounds ].size.height - 126;

for iPad:

float maxHeight = [[ UIScreen mainScreen ] bounds ].size.height - 171;

This should work for alle Screen sizes...

回答2:

Ok, although you can assign to the preferredContentSize any CGSize it is reduced to max height and width.

Device Orientation (max width, max height):

iPhone 5S Portrait (272, 441.5)
iPhone 5S Landscape (520, 205.5)

iPhone 6 Portrait (327, 540.5)
iPhone 6 Landscape (586, 260.5)

iPhone 6 Plus Portrait (362, 610)
iPhone 6 Plus Landscape (585, 288)

iPad Mini Portrait (535, 853)
iPad Mini Landscape (535, 597)

iPad Portrait (711, 985)
iPad Landscape (967, 729)

How did I get these values?

@IBOutlet weak var sizerView: UIView!

inside viewDidLoad:

preferredContentSize = CGSizeMake(0, 2000)
dispatch_after(1, dispatch_get_main_queue(), { //it needs time to render itself
    label.text = NSStringFromCGSize(self.sizerView.bounds.size) //here you have MAX VALUES
}

回答3:

It seems, that iOS is adding an UIView-Encapsulated-Layout-Height constraint to your own constraints:

(
    "<NSLayoutConstraint:0x610000280640 V:[_UILayoutGuide:0x7f92d0513810]-(500)-[UILabel:0x7f92d040cb20'Hello World']>",
    "<NSLayoutConstraint:0x610000280690 V:[UILabel:0x7f92d040cb20'Hello World']-(500)-[_UILayoutGuide:0x7f92d0515100]>",
    "<_UILayoutSupportConstraint:0x6100002a2f40 V:[_UILayoutGuide:0x7f92d0513810(0)]>",
    "<_UILayoutSupportConstraint:0x6100002a2ee0 V:|-(0)-[_UILayoutGuide:0x7f92d0513810]   (Names: '|':UIView:0x7f92d040c810 )>",
    "<_UILayoutSupportConstraint:0x6100002a3000 V:[_UILayoutGuide:0x7f92d0515100(0)]>",
    "<_UILayoutSupportConstraint:0x6100002a2fa0 _UILayoutGuide:0x7f92d0515100.bottom == UIView:0x7f92d040c810.bottom>",
    "<NSLayoutConstraint:0x60800009e780 'UIView-Encapsulated-Layout-Height' V:[UIView:0x7f92d040c810(628)]>"
)

This constraint forces the widget to have the maximum height. You can get it's value like this:

- (void)widgetPerformUpdateWithCompletionHandler:(void (^)(NCUpdateResult))completionHandler {

    for (NSLayoutConstraint *constraint in self.view.constraints) {
        if ([constraint.identifier isEqualToString:@"UIView-Encapsulated-Layout-Height"]) {
            NSLog(@"Height: %@", @(constraint.constant));
        }
    }

    completionHandler(NCUpdateResultNewData);
}

回答4:

To get the max height of the widgets active display mode, do this in your UIViewController:

let context = self.extensionContext
if let context = context{
    let height = context.widgetMaximumSize(for: context.widgetActiveDisplayMode).height
}

To get the max height of expanded and compact individually regardless of the current display mode, do this:

var context = self.extensionContext
if let context = context{
    let compactHeight = context.widgetMaximumSize(for: .compact).height
    let expandedHeight = context.widgetMaximumSize(for: .expanded).height
}