Revise SDL-0119 SDL Passenger Mode

[joeljfischer]

Introduction

Update SDL-0119 SDL Passenger mode for usability improvements: first, to swipe down instead of up to match most default animations; second, to only show the lock screen again if the dismissal enabled parameter is set to false after it had been set to true.

Motivation

The design and usability of this feature on the mobile side is lacking in the current proposal and can be improved.

Proposed solution

The changes are two part:

1. Change the swipe up gesture to be swipe down. Because iOS and many android phones have a default modal animation of transitioning from the bottom and back to the bottom, a swipe down will follow the movement of the lock screen. This will make more sense to the user than swiping up and the lock screen moving down.

2. Change the re-appearance of the lock screen to only re-appear if both the lock screen becomes required again and the lockScreenDismissalEnabled parameter changes to false. If the lockScreenDismissalEnabled parameter is true, and the lock screen has been dismissed, it should remain dismissed. Otherwise, this would lead to a very frustrating user experience for a passenger who is in stop and go traffic as the lock screen will constantly re-appear.

Potential downsides

1. Android's default animation can vary by phone and may not always be a "from the bottom" modal animation. Therefore the swipe may not always match the animation.

2. If the lock screen was dismissed, it cannot be re-enabled unless the head unit sets the lockScreenDismissalEnabled to false.

Impact on existing code

The mobile libraries will need to be updated

Alternatives considered

1. Instead of the dismissal persisting until lockScreenDismissalEnabled is set to false, it could only persist until the device is locked.

[joeljfischer]

@theresalech this is ready for review