10/11/18. Introduction Panel Class Window Class Dialog class FileDialog class Menu, MenuItem class

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1 A.Prof. Tran Van Lang, PhD Vietnam Academy of Science and Technology (VAST) Introduction Panel Class Window Class Dialog class FileDialog class Menu, MenuItem class Components A container is a component which can contain other components inside itself. Container Other containers include window, frame, dialog, and panel All the containers of of AWT were inheritaned from the Container abstract class There are 3 main classes Panel Class ScrollPane Class Window Class Panel Applet ScrollPane FileDialog Dialog Window Frame 1

2 Panel is the simplest container class. A panel provides space in which an application can attach any other component, including other panels. The constructors of Panel Class Panel(): Creates a new panel using the default layout manager. Panel(LayoutManager): Creates a new panel with the specified layout manager. We want to build a program with following interface (ExContainer.java): 2

3 Panel is a component, so we can use the add method to attach Label, List,... into its. Concurrently, it also is a container, so we also use the add method to attach its into other window (for example, Frame) To layout the Panel, using layout manager class such as FlowLayout, GridLayout, BorderLayout,... For example, new Panel( new FlowLayout() ); p1.setlayout( new GridLayout(6,1) ); //Grid with 6 rows and 1 conlumn The Window inherites from Container Class A Window object is a top-level window with no borders and no menubar. The default layout for a window is BorderLayout. A window must have either a frame, dialog, or another window defined as its owner when it's constructed. The Constructors of Window Class: Window(Frame): Constructs a new, initially invisible window with the specified Frame as its owner Window(Window): Constructs a new, initially invisible window with the specified Window as its owner Window(Window,GraphicsCongiguration): Constructs a new, initially invisible window with the specified owner Window and a GraphicsConfiguration of a screen device. 3

4 The popular methods as follows: void setbackground(color): Sets the background color of this window. void setbound(int x,int y,int w,int h): Moves and resizes this component. void setlocation(int x, int y): Moves this component to a new location. void setsize(int w, int h): Resizes this component so that it has width width and height height dispose(): Releases all of the native screen resources used by this Window, its subcomponents, and all of its owned children. void addwindowlistener( WindowListener): Adds the specified window listener to receive window events from this window. ExFrame.java A Frame is a top-level window with a title and a border, it inherited from Window Class. The default layout for a frame is BorderLayout. The size of the frame includes any area designated for the border. The dimensions of the border area may be obtained using the getinsets method, however, since these dimensions are platform-dependent, a valid insets value cannot be obtained until the frame is made displayable by either calling pack or show. 4

5 A Dialog is a top-level window with a title and a border that is typically used to take some form of input from the user. The size of the dialog includes any area designated for the border. The Constructors and Description of Dialog class: Dialog(Dialog/Frame/Window owner): Constructs an initially invisible, modeless Dialog with the specified owner Dialog /Frame/Window and an empty title. Dialog(Dialog/Frame/Window owner, String title): Constructs an initially invisible, modeless Dialog with the specified owner Dialog /Frame/Window and title. Dialog(Dialog/Frame/Window owner, String title, boolean modal): Constructs an initially invisible Dialog with the specified owner Dialog/Frame/Window, title, and modality. Create the following Message dialogs provide information to the user as a API 5

6 ExDialog program with 2 Message Dialogs The Popular methods of Dialog class boolean ismodal(): Indicates whether the dialog is modal void setmodal( int ): Specifies whether this dialog should be modal void setresizable(): Sets whether this dialog is resizable by the user void settitle( String): Sets the title of the Dialog String gettitle(): Gets the title of the dialog void dispose(): Releases all of the native screen resources used by this Dialog, its subcomponents, and all of its owned children The FileDialog class displays a dialog window from which the user can select a file The Constructor FileDialog(Dialog/Frame): Creates a file dialog for loading a file. FileDialog(Dialog/Frame, String title): Creates a file dialog window with the specified title for loading a file. FileDialog(Dialog/Frame, String title, int mode): Creates a file dialog window with the specified title for loading (FileDialog.LOAD) or saving (FileDialof.SAVE) a file. The popular methods: String getdirectory(): Gets the directory of this file dialog. String getfile(): Gets the selected file of this file dialog. void setdirectory(string dir): Sets the directory of this file dialog window to be the specified directory. void setfile(string file): Sets the selected file for this file dialog window to be the specified file. 6

7 Open file to read by Scanner Class Example: ExFileDialog class was used to open file for reading When the Open button had been clicked, then actionperformed() method was invoked We can build a PrintError Class to display into TextArea My an application to handle your book library. It can you know location of book in bookcase, list of books on loan. 7

8 A Menu object is a pull-down menu component that is deployed from a menu bar. MenuComponent Each item in a menu must belong to the MenuItem Class. It can be an instance of MenuItem, a submenu (an instance of Menu), or a check box (an instance of CheckboxMenuItem). <<Interface>> ItemSelectable CheckboxMenuItem MenuItem <<Interface>> MenuContainer Menu MenuBar The Constructor of Menu Class: Menu(): Constructs a new menu with an empty label. Menu(String label): Constructs a new menu with the specified label The Popular Method add(menuitem): Adds the specified menu item to this menu addseparator(): Adds a separator line, or a hypen, to the menu at the current position All items in a menu must belong to the class MenuItem, or one of its subclasses. The Constructor: MenuItem(String): Constructs a new MenuItem with the specified label and no keyboard shortcut MenuItem(String,MenuShortcut): Create a menu item with an associated keyboard shortcut The MenuShortcut class represents a keyboard accelerator for a MenuItem. 8

9 The Popular Methods addactionlistener(actionevent): Adds the specified action listener to receive action events from this menu item. void setenabled(boolean): Sets whether or not this menu item can be chosen. String getlabel(): Gets the label for this menu item. void setlabel(string): Sets the label for this menu item to the specified label. This class represents a check box that can be included in a menu. Selecting the check box in the menu changes its state from "on" to "off" or from "off" to "on." When a check box menu item is selected, AWT sends an item event to the item. The Constructors CheckboxMenuItem(): Create a check box menu item with an empty label. CheckboxMenuItem(label): Create a check box menu item with the specified label. CheckboxMenuItem(label, boolean state): Create a check box menu item with the specified label and state. The Popular Methods additemlistener(itemlistener l): Adds the specified item listener to receive item events from this check box menu item. Need to implement the public void itemstatechanged(itemevent) Method void setstate(boolean b): Sets this check box menu item to the specifed state. boolean getstate(): Determines whether the state of this check box menu item is "on" or "off." 9

10 The MenuBar class encapsulates the platform's concept of a menu bar bound to a frame. In order to associate the menu bar with a Frame object, call the frame's setmenubar method. There's only one Constructor to create a new menu bar. The Popular Methods: add(menu): Adds the specified menu to the menu bar sethelpmenu(menu): Sets the specified menu to be this menu bar's help menu. Build an application with following functions: Open file to view Convert the Solar year to Lunar year Find the prime numbers Choice the major subjects The ExApp Class with interface as next frame In NetBeans, data files (the flower as picture) were store in parents folder of src folder 10

11 There're 3 main Menu in application: file, utilities and help In file Menu, there're following MenuItem: Open, Open Recent, View and Exit. However, Open Recent is a Sub Menu; so there're MenuItems in its. These MenuItems are filename and directory of files opened by MenuFileDialog. So, the MenuItems are ChecboxMenuItem. In Utilities Menu: there're 3 MenuItem: Date & Year, Choice major subject and Finding the prime number. Help is an HelpMenu, using sethelpmenu() to create. 11

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13 There are 4 following classes in this application MenuViewFile MenuFileDialog MenuCourse MenuToLunar MenuPrime PrintError This class is a Dialog class, so it need to extend Dialog This is source code to read data from file to display into the TextArea (as previous ExFileDialog example) 13