| ### Shifting a flexible header off-screen |
| |
| A flexible header that tracks a scroll view will expand and contract its height in reaction to |
| scroll view events. A flexible header can also shift off-screen in reaction to scroll view events |
| by changing the flexible header's behavior. |
| |
| <!--<div class="material-code-render" markdown="1">--> |
| #### Swift |
| ```swift |
| headerViewController.headerView.shiftBehavior = .enabled |
| ``` |
| |
| #### Objective-C |
| ```objc |
| headerViewController.headerView.shiftBehavior = MDCFlexibleHeaderShiftBehaviorEnabled; |
| ``` |
| <!--</div>--> |
| |
| > Important: when a flexible header shifts off-screen it **will not hide the content views**. Your |
| > content views are responsible for hiding themselves in reaction to the flexible header shifting |
| > off-screen. Read the section on [Reacting to frame changes](#reacting-to-frame-changes) for more |
| > information. |
| |
| It is also possible to hide the status bar when shifting the flexible header off-screen. Enable this |
| behavior by setting the `enabledWithStatusBar` behavior and implementing |
| `childViewControllerForStatusBarHidden` on the parent view controller. |
| |
| <!--<div class="material-code-render" markdown="1">--> |
| #### Swift |
| ```swift |
| headerViewController.headerView.shiftBehavior = .enabledWithStatusBar |
| |
| override func childViewControllerForStatusBarHidden() -> UIViewController? { |
| return headerViewController |
| } |
| ``` |
| |
| #### Objective-C |
| ```objc |
| headerViewController.headerView.shiftBehavior = MDCFlexibleHeaderShiftBehaviorEnabledWithStatusBar; |
| |
| - (UIViewController *)childViewControllerForStatusBarHidden { |
| return _headerViewController; |
| } |
| ``` |
| <!--</div>--> |
