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Setting the view's frame is an important part of migrating from MDCAppBar to MDCAppBarViewController. Failure to do so can result in the app bar's width not matching the parent view's width.
App bars: top
The Material Design top app bar displays information and actions relating to the current view.
Related components
Overview
App bar is composed of the following components:
It is essentially a FlexibleHeader with a HeaderStackView and NavigationBar added as subviews.
MDCAppBarViewController is the primary API for the component. All integration strategies will
make use of it in some manner. Unlike UIKit, which shares a single UINavigationBar instance across
many view controllers in a stack, app bar relies on each view controller creating and managing its
own MDCAppBarViewController instance.
Installation
Usage
- Typical use: View controller containment, as a navigation controller
- Typical use: View controller containment, as a child
- Typical use: View controller containment, as a container
- Typical use: Tracking a scroll view
- Typical use: Enabling observation of the tracking scroll view
- UINavigationItem support
- Interactive background views
- Adjusting the top layout guide of a view controller
Behavioral flags
A behavioral flag is a temporary API that is introduced to allow client teams to migrate from an old behavior to a new one in a graceful fashion. Behavioral flags all go through the following life cycle:
- The flag is introduced. The default is chosen such that clients must opt in to the new behavior.
- After some time, the default changes to the new behavior and the flag is marked as deprecated.
- After some time, the flag is removed.
- Recommended behavioral flags
- Removing safe area insets from the min/max heights
- Enabling top layout guide adjustment
- Enabling inferred top safe area insets
See the FlexibleHeader documentation for additional usage guides.