Structure your media app 3) Customize playback controls

3) Customize playback controls

In addition to deciding how your app content is organized for navigating and browsing (tasks 1 and 2), you need to decide whether you want a queue or any custom controls for playing the content.

Car makers take care of implementing and styling the playback view, minimized control bar, and queue. They also provide a basic set of playback controls, including Play/Pause, Next, Previous, and Overflow. If these controls are sufficient for your app, then you’re done.

However, if you want to provide a queue or access to additional playback actions beyond the ones that car makers provide, you need to decide:

  • Whether to display thumbnails for queue items
  • Whether to display an icon or elapsed time for the currently playing item in the queue
  • Whether to include previously played items in the queue
  • Which custom actions you want on the control bar, and whether they should replace the car makers’ Next and Previous controls
  • What the icons representing the relevant states of each action (such as available and disabled) will look like

Technical note:
Custom actions display in the order in which they are added to the PlaybackState. Their icons are specified as icon resources. For details, consult Add custom playback actions.

Keep in mind the guidelines below.

Playback control guidelines Expand and collapse content An arrow that points down when collapsed and points up when expanded.

Requirement level

Guidelines

MUST

App developers must:

  • Provide monochrome (black or white) vector icons for any custom actions they add, and change them dynamically to indicate state

SHOULD

App developers should:

  • If using text (including numbers) in an icon, utilize the maximum space in the bounding box to make the text as large and readable as possible

MAY

App developers may:

  • Provide monochrome (black or white) vector icons for up to 8 custom actions

Rationale:

  • Consistent app UI: App developers need to align the interfaces for custom actions in media apps with similar actions familiar to their users on other devices.
  • Glanceability: Text can appear smaller when paired with iconography, so text in icons should be maximized within the available space.

Queue guidelines Expand and collapse content An arrow that points down when collapsed and points up when expanded.

The following considerations apply if you decide to implement a queue to allow users to view currently playing and upcoming content.

Requirement Level

Guidelines

SHOULD

App developers should:

  • Provide an indicator for the currently playing queue item
  • Include previously played items in the queue

MAY

App developers may:

  • Provide thumbnails for queue items
  • Indicate the currently playing item with either an icon or by displaying elapsed time

Note:
Car makers can choose to disable the display of thumbnails. They can also choose to disable display of icons and elapsed time for the currently playing item.

Rationale:

  • Glanceable UI: Users should be able to see what's currently playing at a glance.