System.Hardware.PiLcd.UserInterface

Displays a simple user interface. The first line of the display is used as a "list box", where the user can scroll through a list of items one at a time using the up and down buttons. The second line of the display is used for virtual "buttons", such as "OK" and "Cancel". The user uses the left and right buttons to select a virtual "button". When the user presses the Select button, the interaction is considered done, and the calling program is given the list item and button selection that the user made.

User interface

data UiData

The data to be displayed in the user interface.

Constructors

UiData

Fields

• udList :: [Text]

  items to be displayed one-at-a-time on the first line

• udButtons :: [Text]

  buttons to be displayed on the second line

Instances

Eq UiData

Methods

(==) :: UiData -> UiData -> Bool

(/=) :: UiData -> UiData -> Bool

Ord UiData

Methods

compare :: UiData -> UiData -> Ordering

(<) :: UiData -> UiData -> Bool

(<=) :: UiData -> UiData -> Bool

(>) :: UiData -> UiData -> Bool

(>=) :: UiData -> UiData -> Bool

max :: UiData -> UiData -> UiData

min :: UiData -> UiData -> UiData

Read UiData

Methods

readsPrec :: Int -> ReadS UiData

readList :: ReadS [UiData]

readPrec :: ReadPrec UiData

readListPrec :: ReadPrec [UiData]

Show UiData

Methods

showsPrec :: Int -> UiData -> ShowS

show :: UiData -> String

showList :: [UiData] -> ShowS

data UiState

The current state of the user interaction.

Constructors

UiState

Fields

• usList :: Int

  index of item from udList currently displayed

• usButtons :: Int

  index of button from udButtons currently highlighted

• usInternal :: InternalState

  opaque data

Instances

Eq UiState

Methods

(==) :: UiState -> UiState -> Bool

(/=) :: UiState -> UiState -> Bool

Ord UiState

Methods

compare :: UiState -> UiState -> Ordering

(<) :: UiState -> UiState -> Bool

(<=) :: UiState -> UiState -> Bool

(>) :: UiState -> UiState -> Bool

(>=) :: UiState -> UiState -> Bool

max :: UiState -> UiState -> UiState

min :: UiState -> UiState -> UiState

Show UiState

Methods

showsPrec :: Int -> UiState -> ShowS

show :: UiState -> String

showList :: [UiState] -> ShowS

data InternalState

Opaque data.

Instances

Eq InternalState

Methods

(==) :: InternalState -> InternalState -> Bool

(/=) :: InternalState -> InternalState -> Bool

Ord InternalState

Methods

compare :: InternalState -> InternalState -> Ordering

(<) :: InternalState -> InternalState -> Bool

(<=) :: InternalState -> InternalState -> Bool

(>) :: InternalState -> InternalState -> Bool

(>=) :: InternalState -> InternalState -> Bool

max :: InternalState -> InternalState -> InternalState

min :: InternalState -> InternalState -> InternalState

Show InternalState

Methods

showsPrec :: Int -> InternalState -> ShowS

show :: InternalState -> String

showList :: [InternalState] -> ShowS

defaultUiState :: UiState

Defaults to displaying the first list item (index 0) and highlighting the first button (index 0).

runUi

Arguments

:: UiData

Data to display in the UI

-> UiState

Current state of the interaction

-> Maybe ButtonEvent

optional button press/release

-> Int

Number of columns in the LCD

-> ([Text], UiState, Bool)

text to display, new UI state, and a flag indicating whether the interaction is done (i. e. user has pressed and released the "Select" button)

Computes the text which should be displayed for the current state of the UI, and optionally applies a button press/release to the state.

Buttons

data Button

Indicates one of the five buttons on the LCD+Keypad kit.

Constructors

ButtonSelect

ButtonRight

ButtonDown

ButtonUp

ButtonLeft

Instances

Bounded Button

Methods

minBound :: Button

maxBound :: Button

Enum Button

Methods

succ :: Button -> Button

pred :: Button -> Button

toEnum :: Int -> Button

fromEnum :: Button -> Int

enumFrom :: Button -> [Button]

enumFromThen :: Button -> Button -> [Button]

enumFromTo :: Button -> Button -> [Button]

enumFromThenTo :: Button -> Button -> Button -> [Button]

Eq Button

Methods

(==) :: Button -> Button -> Bool

(/=) :: Button -> Button -> Bool

Ord Button

Methods

compare :: Button -> Button -> Ordering

(<) :: Button -> Button -> Bool

(<=) :: Button -> Button -> Bool

(>) :: Button -> Button -> Bool

(>=) :: Button -> Button -> Bool

max :: Button -> Button -> Button

min :: Button -> Button -> Button

Read Button

Methods

readsPrec :: Int -> ReadS Button

readList :: ReadS [Button]

readPrec :: ReadPrec Button

readListPrec :: ReadPrec [Button]

Show Button

Methods

showsPrec :: Int -> Button -> ShowS

show :: Button -> String

showList :: [Button] -> ShowS

data ButtonDirection

Indicates whether a button was pressed or released.

Constructors

Press

Release

Instances

Bounded ButtonDirection

Methods

minBound :: ButtonDirection

maxBound :: ButtonDirection

Enum ButtonDirection

Methods

succ :: ButtonDirection -> ButtonDirection

pred :: ButtonDirection -> ButtonDirection

toEnum :: Int -> ButtonDirection

fromEnum :: ButtonDirection -> Int

enumFrom :: ButtonDirection -> [ButtonDirection]

enumFromThen :: ButtonDirection -> ButtonDirection -> [ButtonDirection]

enumFromTo :: ButtonDirection -> ButtonDirection -> [ButtonDirection]

enumFromThenTo :: ButtonDirection -> ButtonDirection -> ButtonDirection -> [ButtonDirection]

Eq ButtonDirection

Methods

(==) :: ButtonDirection -> ButtonDirection -> Bool

(/=) :: ButtonDirection -> ButtonDirection -> Bool

Ord ButtonDirection

Methods

compare :: ButtonDirection -> ButtonDirection -> Ordering

(<) :: ButtonDirection -> ButtonDirection -> Bool

(<=) :: ButtonDirection -> ButtonDirection -> Bool

(>) :: ButtonDirection -> ButtonDirection -> Bool

(>=) :: ButtonDirection -> ButtonDirection -> Bool

max :: ButtonDirection -> ButtonDirection -> ButtonDirection

min :: ButtonDirection -> ButtonDirection -> ButtonDirection

Read ButtonDirection

Methods

readsPrec :: Int -> ReadS ButtonDirection

readList :: ReadS [ButtonDirection]

readPrec :: ReadPrec ButtonDirection

readListPrec :: ReadPrec [ButtonDirection]

Show ButtonDirection

Methods

showsPrec :: Int -> ButtonDirection -> ShowS

show :: ButtonDirection -> String

showList :: [ButtonDirection] -> ShowS

data ButtonEvent

Indicates a press or release of one of the five buttons on the LCD+Keypad kit.

Constructors

ButtonEvent Button ButtonDirection

Instances

Eq ButtonEvent

Methods

(==) :: ButtonEvent -> ButtonEvent -> Bool

(/=) :: ButtonEvent -> ButtonEvent -> Bool

Ord ButtonEvent

Methods

compare :: ButtonEvent -> ButtonEvent -> Ordering

(<) :: ButtonEvent -> ButtonEvent -> Bool

(<=) :: ButtonEvent -> ButtonEvent -> Bool

(>) :: ButtonEvent -> ButtonEvent -> Bool

(>=) :: ButtonEvent -> ButtonEvent -> Bool

max :: ButtonEvent -> ButtonEvent -> ButtonEvent

min :: ButtonEvent -> ButtonEvent -> ButtonEvent

Read ButtonEvent

Methods

readsPrec :: Int -> ReadS ButtonEvent

readList :: ReadS [ButtonEvent]

readPrec :: ReadPrec ButtonEvent

readListPrec :: ReadPrec [ButtonEvent]

Show ButtonEvent

Methods

showsPrec :: Int -> ButtonEvent -> ShowS

show :: ButtonEvent -> String

showList :: [ButtonEvent] -> ShowS