iOS 11 Layout guidance about safe Area for iPhone x

纵饮孤独 提交于 2019-11-27 13:19:31
joern

With iOS11 (and the appearance of iPhoneX) Apple introduced the Safe Area Layout Guide to adapt your views to the iPhoneX.

The Safe Area is the area of the screen that is not overlapped by the notch or the home indicator.

To avoid the issue you are experiencing you have to change your noView's top constraint for iOS11:

if #available(iOS 11, *) {
   let guide = view.safeAreaLayoutGuide
   NSLayoutConstraint.activate([
      noView.topAnchor.constraint(equalTo: guide.topAnchor)
   ])
} else {
   NSLayoutConstraint.activate([
      noView.topAnchor.constraint(equalTo: currentViewController.topLayoutGuide.bottomAnchor)
   ])
}
NSLayoutConstraint.activate([
   noView.leadingAnchor.constraint(equalTo: currentViewController.view.leadingAnchor),
   noView.trailingAnchor.constraint(equalTo: currentViewController.view.trailingAnchor),
   noView.heightAnchor.constraint(equalToConstant: 65)
])

Unfortunately that is not all. Because now your noView moves down on iPhone X, but the status bar does not have a red background anymore. You have add a red background color behind the status bar:

You could make things a lot easier by using a UINavigationController (with a red navigation bar):

With this approach you don't have to set any constraints! The systems does all the adjustments for you automatically.

In Objective-C for top and bottom margin when on iPhone-X

if (@available(iOS 11, *)) {

    NSLayoutConstraint *bottomConstraint   = [NSLayoutConstraint constraintWithItem:self.childView
                                                                          attribute:NSLayoutAttributeBottom
                                                                          relatedBy:NSLayoutRelationEqual
                                                                             toItem:self.parentView.safeAreaLayoutGuide
                                                                          attribute:NSLayoutAttributeBottom
                                                                         multiplier:1.0
                                                                           constant:0];


    NSLayoutConstraint *topConstraint   = [NSLayoutConstraint constraintWithItem:self.childView
                                                                   attribute:NSLayoutAttributeTop
                                                                   relatedBy:NSLayoutRelationEqual
                                                                      toItem:self.parentView.safeAreaLayoutGuide
                                                                   attribute:NSLayoutAttributeTop
                                                                  multiplier:1.0
                                                                    constant:0];


} else {

    NSLayoutConstraint *bottomConstraint   = [NSLayoutConstraint constraintWithItem:self.childView
                                                                      attribute:NSLayoutAttributeBottom
                                                                      relatedBy:NSLayoutRelationEqual
                                                                         toItem:self.parentView
                                                                      attribute:NSLayoutAttributeBottom
                                                                     multiplier:1.0
                                                                       constant:0];


    NSLayoutConstraint *topConstraint   = [NSLayoutConstraint constraintWithItem:self.childView
                                                                   attribute:NSLayoutAttributeTop
                                                                   relatedBy:NSLayoutRelationEqual
                                                                      toItem:self.parentView
                                                                   attribute:NSLayoutAttributeTop
                                                                  multiplier:1.0
                                                                    constant:0];

}

If you don't want to use a UINavigationController but you want to have a navigation bar, you can do this way (using a UIImageView):

https://medium.com/@kahseng.lee123/creating-custom-navigation-bar-tab-bar-for-iphone-x-f03b1e1827d3

Or you can create a view and set its top constraint to the top of the superview and its bottom contraint to the top of the navigation bar. Don't forget to make it red. :-)

Set height constrain of headerView according to the device.

if iPhoneX {
NSLayoutConstraint(item: noView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1.0, constant: 64+24).isActive = true
} else {
NSLayoutConstraint(item: noView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1.0, constant: 64).isActive = true
}

And set all the subView's(of headerView) constrain respective to bottom of superview(headerView).

Additional note on why we have added 24 pixel for iphoneX:

    // portrait orientation - status bar is shown
    additionalSafeAreaInsets.top = 24.0
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