Overview

Sadly, roku SceneGraph has a very limited view architecture. If you come from iOS, Android, or angular, you may be wondering how to know if a view/screen:

• Was first shown
• Shown
• Hidden
• Added to another aggregate container
• Removed from an aggregate container
• Got focus
• Had a child receive focus
• Lost focus

In addition to affording these lifecycle events, maestro also provides familiar aggregate views, to allow composing screens together.

A special BaseScreen subclass, which manages showing, or hiding views. The currentView property informs which view is currently active (i.e. the selected tab, or current view on top of a NavController)

Only one screen is ever visible at a time. A screen's lifecycle methods for focus and visibility will all be managed and can be relied upon for ascertaining the proper state of the screen.

BaseAggregateView subclass which allows you to switch various views. The tabController will display a screen which corresponds to the currently selected item. The screen is created lazily, unless it was specified using addExistingView

• menuItems array of items, which are used to create child screens. The menuItem must have an id, which matches the view passed in with addExistingView, or have it's screenType set to the valid type of a BaseScreen subclass
• currentItem readOnly the currently selected menuItem

• addExistingView - will register the passed in view to be displayed when a menu item with the same id is set as the currentItem
• getViewForMenuItemContent
• changeCurrentItem - will set the currentItem

NavController controls a stack of views stacked one up on the other. When a BaseScreen is added to a NavController it's navController field is set to the navController. In addition the lifecycle methods onAddedToAggregateView and onRemovedFromAggregateView are invoked in accordance with pop, push and reset

• numberOfViews readonly number of Views on the stack
• isLastViewPopped readonly true, if the last view is popped, can be observed
• isAutoFocusEnabled if true then pushed views receive focus

• push - pushes the passed in view onto the stack, and initializes it
• pop - pops current view from the stack
• reset - resets the stack
• resetToIndex - resets the stack to the desired index

DynamicContainer is analogue to iOS's container view. It affords the embedding of screens, within screens. This is useful for:

• Tab switchers
• Sub views (e.g. placing a faux dialog on top of a screen)
• Embedding a forgot password screen inside of another screen

It has one method SetNextView, which will set the current view on the container. Note, you can bind directly to this, in mvvm bindings, as maestro knows how to call node functions.

Allows for display of multiple components on top of each other, in an indexed manner. Set the children with the children field, and then use the index field to specify which child is focused. The MultiContainer will automatically focus on, and scroll to the child at the requested index.

• animationDuration - controls animation speed
• children - the the children of the multiContainer
• index - index of current focused view, if set will jump to view at index
• isAnimated - if false, will jump to index without animating
• needsRecalculating - if true, will force layout again
• yOffsets - collection of values that correspond to each child. Each value will offset the screen position for the corresponding view