brick/programs/ListDemo.hs
2015-07-10 13:25:44 -07:00

92 lines
2.6 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
module Main where
import Control.Lens ((^.))
import Control.Monad (void)
import Data.Monoid
import qualified Graphics.Vty as V
import qualified Brick.Main as M
import qualified Brick.Types as T
import qualified Brick.Widgets.Border as B
import qualified Brick.Widgets.List as L
import qualified Brick.Widgets.Center as C
import qualified Brick.AttrMap as A
import Brick.Widgets.Core
( Widget
, (<+>)
, str
, vLimit
, hLimit
, vBox
, withAttr
)
import Brick.Util (fg, on, bg)
drawUI :: L.List Int -> [Widget]
drawUI l = [ui]
where
label = "Item " <+> cur <+> " of " <+> total
cur = case l^.(L.listSelectedL) of
Nothing -> "-"
Just i -> str (show (i + 1))
total = str $ show $ length $ l^.(L.listElementsL)
box = B.borderWithLabel label $
hLimit 25 $
vLimit 15 $
L.renderList l
ui = C.vCenter $ vBox [ C.hCenter box
, " "
, C.hCenter "Press +/- to add/remove list elements."
, C.hCenter "Press Esc to exit."
]
appEvent :: L.List Int -> V.Event -> M.EventM (M.Next (L.List Int))
appEvent l e =
case e of
V.EvKey (V.KChar '+') [] ->
let el = length $ l^.(L.listElementsL)
in M.continue $ L.listInsert el el l
V.EvKey (V.KChar '-') [] ->
case l^.(L.listSelectedL) of
Nothing -> M.continue l
Just i -> M.continue $ L.listRemove i l
V.EvKey V.KEsc [] -> M.halt l
ev -> M.continue $ T.handleEvent ev l
listDrawElement :: Bool -> Int -> Widget
listDrawElement sel i =
let selStr s = if sel
then withAttr customAttr (str $ "<" <> s <> ">")
else str s
in C.hCenter $ "Item " <+> (selStr $ show i)
initialState :: L.List Int
initialState = L.list (T.Name "list") listDrawElement [0, 1, 2]
customAttr :: A.AttrName
customAttr = L.listSelectedAttr <> "custom"
theMap :: A.AttrMap
theMap = A.attrMap V.defAttr
[ (L.listAttr, V.white `on` V.blue)
, (L.listSelectedAttr, V.blue `on` V.white)
, (customAttr, fg V.cyan)
]
theApp :: M.App (L.List Int) V.Event
theApp =
M.App { M.appDraw = drawUI
, M.appChooseCursor = M.showFirstCursor
, M.appHandleEvent = appEvent
, M.appStartEvent = return
, M.appAttrMap = const theMap
, M.appMakeVtyEvent = id
}
main :: IO ()
main = void $ M.defaultMain theApp initialState