我写了一个小应用程序来跟踪我在电视剧中的进展。该应用程序是用 Haskell 编写的，带有功能响应式编程 (FRP) 和响应式香蕉。
该应用程序可以：
- 在表中添加/删除新电视剧
- 更改系列的季节和剧集
我在编写将新电视剧添加到表格并连接新事件的代码时遇到问题。此处的 CRUD 示例对我没有太大帮助，因为我有更多要求，然后只是从列表中选择一个元素。
如何以 FRP 方式编写类似于 CRUD 示例中的reactiveTable函数的函数reactiveListDisplay？网络编译后，如何为删除按钮和季节和剧集旋转按钮添加事件？
data Series = Series { name :: String
, season :: Int
, episode :: Int
}
insertIntoTable :: TableClass t => t -> SeriesChangeHandler -> SeriesRemoveHandler -> Series -> IO ()
insertIntoTable table changeHandler removeHandler (Series name s e) = do
(rows, cols) <- tableGetSize table
tableResize table (rows+1) cols
nameLabel <- labelNew $ Just name
adjustmentS <- adjustmentNew (fromIntegral s) 1 1000 1 0 0
adjustmentE <- adjustmentNew (fromIntegral e) 1 1000 1 0 0
seasonButton <- spinButtonNew adjustmentS 1.0 0
episodeButton <- spinButtonNew adjustmentE 1.0 0
removeButton <- buttonNewWithLabel "remove"
let getSeries = do
s <- spinButtonGetValue seasonButton
e <- spinButtonGetValue episodeButton
return $ Series name (round s) (round e)
handleSeries onEvent widget handler = do
onEvent widget $ do
series <- getSeries
handler series
handleSeries onValueSpinned seasonButton changeHandler
handleSeries onValueSpinned episodeButton changeHandler
onPressed removeButton $ do
series <- getSeries
containerRemove table nameLabel
containerRemove table seasonButton
containerRemove table episodeButton
containerRemove table removeButton
removeHandler series
let tadd widget x = tableAdd table widget x (rows - 1)
tadd nameLabel 0
tadd seasonButton 1
tadd episodeButton 2
tadd removeButton 3
widgetShowAll table
main :: IO ()
main = do
initGUI
window <- windowNew
scroll <- scrolledWindowNew Nothing Nothing
table <- tableNew 1 5 True
addButton <- buttonNewWithLabel "add series"
vbox <- vBoxNew False 10
containerAdd window vbox
boxPackStart vbox addButton PackNatural 0
let networkDescription :: forall t. Frameworks t => Moment t ()
networkDescription = do
addEvent <- eventButton addButton
(changeHandler,fireChange) <- liftIO $ newAddHandler
changeEvent <- fromAddHandler changeHandler
(removeHandler,fireRemove) <- liftIO $ newAddHandler
removeEvent <- fromAddHandler removeHandler
let insertIntoTable' = insertIntoTable table fireChange fireRemove
addSeries e = do
s <- addSeriesDialog
liftIO $ insertIntoTable' s
liftIO $ mapM_ insertIntoTable' initSeries
reactimate $ addSeries <$> addEvent
reactimate $ updateSeries conn <$> changeEvent
reactimate $ removeSeries conn <$> removeEvent
network <- compile networkDescription
actuate network
onDestroy window $ do
D.disconnect conn
mainQuit
widgetShowAll window
mainGUI
我想重构 insertIntoTable 方法以使用事件和行为，而不是使用简单的回调。
编辑：
我已经尝试了带有ListStore后端的 gtk TreeView 。在这种情况下，您不需要动态事件切换。我编写了下面的函数来获取插入、更改和删除事件的列表行为。它有效^^reactiveList
reactiveList :: (Frameworks t)
=> ListStore a
-> Event t (Int,a) -- insert event
-> Event t (Int,a) -- change event
-> Event t (Int,a) -- remove event
-> Moment t (Behavior t [a])
reactiveList store insertE changeE removeE = do
(listHandler,fireList) <- liftIO $ newAddHandler
let onChange f (i,a) = do
f i a
list <- listStoreToList store
fireList list
reactimate $ onChange (listStoreInsert store) <$> insertE
reactimate $ onChange (listStoreSetValue store) <$> changeE
reactimate $ onChange (const . listStoreRemove store) <$> removeE
initList <- liftIO $ listStoreToList store
fromChanges initList listHandler
main :: IO ()
main = do
initGUI
window <- windowNew
addButton <- buttonNewWithLabel "add series"
vbox <- vBoxNew False 10
seriesList <- listStoreNew (initSeries :: [Series])
listView <- treeViewNewWithModel seriesList
treeViewSetHeadersVisible listView True
let newCol title newRenderer f = do
col <- treeViewColumnNew
treeViewColumnSetTitle col title
renderer <- newRenderer
cellLayoutPackStart col renderer False
cellLayoutSetAttributes col renderer seriesList f
treeViewAppendColumn listView col
return renderer
newCol "Image" cellRendererPixbufNew $ \s -> [cellPixbuf :=> newPixbuf s]
newCol "Name" cellRendererTextNew $ \s -> [cellText := name s]
seasonSpin <- newCol "Season" cellRendererSpinNew $ \s ->
[ cellRendererSpinAdjustment :=> adjustmentNew (fromIntegral (season s)) 1 1000 1 0 0
, cellText := (show $ season s)
, cellTextEditable := True
]
episodeSpin <- newCol "Episode" cellRendererSpinNew $ \s ->
[ cellRendererSpinAdjustment :=> adjustmentNew (fromIntegral (episode s)) 1 1000 1 0 0
, cellText := (show $ episode s)
, cellTextEditable := True
]
containerAdd window vbox
boxPackStart vbox listView PackGrow 0
boxPackStart vbox addButton PackNatural 0
let networkDescription :: forall t. Frameworks t => Moment t ()
networkDescription = do
(addHandler,fireAdd) <- liftIO $ newAddHandler
maybeSeriesE <- fromAddHandler addHandler
(removeHandler,fireRemove) <- liftIO $ newAddHandler
removeE <- fromAddHandler removeHandler
-- when the add button was pressed,
-- open a dialog and return maybe a new series
askSeriesE <- eventButton addButton
reactimate $ (const $ fireAdd =<< askSeries) <$> askSeriesE
-- ommit all nothing series
let insertE = filterJust maybeSeriesE
insert0E = ((,) 0) <$> insertE
seasonSpinE <- eventSpin seasonSpin seriesList
episodeSpinE <- eventSpin episodeSpin seriesList
let changeSeason (i,d,s) = (i,s {season = round d})
changeEpisode (i,d,s) = (i,s {episode = round d})
let changeE = (changeSeason <$> seasonSpinE) `union` (changeEpisode <$> episodeSpinE)
listB <- reactiveList seriesList insert0E changeE removeE
listE <- (changes listB)
reactimate $ (putStrLn . unlines . map show) <$> listE
reactimate $ insertSeries conn <$> insertE
reactimate $ updateSeries conn . snd <$> changeE
reactimate $ removeSeries conn . snd <$> removeE
return ()
network <- compile networkDescription
actuate network
onDestroy window $ do
D.disconnect conn
mainQuit
widgetShowAll window
mainGUI
我愿意接受意见和建议。