Creating GUIs 10 25 2010 Opening Discussion No IcP today Questions on the assignment Minute essay comments Difference between Source and Scanner Motivation While text based programs still play a very big role in computing it is mostly behind the scenes You are far more used to working with Graphical User Interfaces GUIs It is time that we learn how to write GUIs in Scala Libraries There are three libraries that will wind up being relevant to our discussion java awt The Abstract Windowing Toolkit Original Java GUI library javax swing Swing was built on top of AWT to be more flexible scala swing Scala code wrapped around Java Swing to aid Scala GUI programming Making a Window In order to write a GUI we need to start by popping up a window For the main window of a GUI we will make a MainFrame For other windows there are Frame and Dialog types We can set the title and size fields of the MainFrame when we create it Set visible to true to bring up the window Oddly we have to prevent the script from stopping Active Components GUIs are made from components Use scala swing package Button text String action Unit new CheckBox label String new ComboBox items Seq A selected Boolean selection index to get the index of the current selection new EditorPane contentType String text String More Components new FormattedTextField format String text String that will tell you the text new Label text String new ListView items Seq A Use collection selection indices to interact with the index values that are selected new PasswordField or new PasswordField text String text String will tell you the text More Components new ProgressBar min Int max Int and value Int new RadioButton text String new ScrollBar selected Boolean minimum maximum and value are all Ints Generally use ScrollPane new Slider min max value orientation Still More Components new Table rowData Array Array Any columnNames Seq Any new TextArea text String text String new TextField text String text String Panes and Panels We build complex GUIs by nesting panels and panes BorderPanel Can hold up to five different components in the north south east west and center positions Add to the layout as a tuple of Component Position BoxPanel Can hold a number of components either vertically or horizontally each takes the space it needs Use new BoxPanel Orientation Vertical Use contents Button text action More Panels FlowPanel GridBagPanel Components are laid out from left to right wrapping like text in a word processor You can pass a variable length list of components as an argument at construction or add the components to contents This panel is more complex GridPanel Holds a regular grid of components You specify how many rows and columns the grid has at creation Panes ScrollPane SplitPane Holds a single component passed in as an argument at construction Scroll bars automatic Two components separated by a moveable bar new SplitPane Orientation Horizontal leftComp rightComp TabbedPane One component shown at a time Tabs are always shown Add components by adding Pages to the page object pages new Page A Tab tabComponent Menus Windows can set the MenuBar Add Menu objects to the contents of the MenuBar Add MenuItems to the contents of the Menus new MenuItem Action Exit exit 0 GUI for Pokemon Let s spend the rest of class laying out and coding up a GUI we could use to edit our Pokemon Minute Essay Is there some type of GUI you would like to have as assignment 5 Turn in assignment 4 today Interclass problem Create a GUI for a calculator or something else you think is interesting
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