SWT & JFace. Подключаем SWT. "Hello, World" in SWT. Создание элементов SWT. Освобождение ресурсов в SWT

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SWT & JFace

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Подключаем SWT

  • org.eclipse.swt_3.5.2.v3557f.jar
  • org.eclipse.swt.win32.win32.x86_3.5.2.v3557f.jar

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"Hello, World" in SWT

import org.eclipse.swt.widgets.*; import org.eclipse.swt.SWT; public class HelloWorld { public static void main(String[] args) { Display display = new Display(); Shell shell = new Shell(display); Label label = new Label(shell, SWT.CENTER); label.setText("Hello, World"); label.setBounds(shell.getClientArea()); shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } display.dispose(); } }

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Создание элементов SWT

  • Всегда создаётся пара объектов
    • Label label = new Label(shell, SWT.CENTER);
    • //что решает ряд проблем, например (MFC)
    • CButton button; // Construct the C++ object on the stack CString str = _T("Hi"); // Create a CString to text button.SetWindowText(str); // Set the button text-PROBLEM!
    • button.Create(…); // Creates the Windows widget
  • Родительский эл. и стиль
    • Label label = new Label(shell, SWT.CENTER);

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Освобождение ресурсов в SWT

  • Rule 1 : If You Created it, You Dispose It
    • Color color1 = new Color(display, 255, 0, 0);
    • ………….
    • Rule 1 says you created it, so you must dispose it when you are done using it, like this:
    • color1.dispose();
    • However, if you don't call a constructor to get a resource, you must not dispose the resource:
    • Color color2 = display.getSystemColor(SWT.COLOR_RED);
    • …………..

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  • Rule 2 : Disposing the Parent Disposes the Children
    • // Create the text field
    • Text text = new Text(shell, SWT.BORDER);
    • // Create the new font
    • Font font = new Font(display, "Arial", 14, SWT.BOLD);
    • // Set the font into the text field
    • text.setFont(font);
    • ???.dispose();

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  • Rule 3 : Ignoring Disposed Objects
    • org.eclipse.swt.SWTException: Widget is disposed at org.eclipse.swt.SWT.error(SWT.java:2332) at org.eclipse.swt.SWT.error(SWT.java:2262) at org.eclipse.swt.widgets.Widget.error(Widget.java:385) at org.eclipse.swt.widgets.Control.getDisplay(Control.java:735) at org.eclipse.swt.widgets.Widget.isValidThread(Widget.java:593) at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:315) at org.eclipse.swt.widgets.Text.getText(Text.java:705) at Broken.main(Version.java:24)

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Display object

  • void asyncExec(Runnable runnable)
    • Gives non-user-interface threads the ability to invoke the protected functions of the SWT widget classes. The user-interface thread performs the code (invokes the run() method) of the runnable at its next "reasonable opportunity." This function returns immediately.
  • void syncExec(Runnable runnable)
    • Like asyncExec(), but this function returns after the run method of the Runnable object returns.
  • void update()
    • Causes all pending paint requests to be processed.
  • static Display findDisplay (Thread thread)
    • Given a user-interface thread, this function returns the associated Display object. If the given thread isn't a user-interface thread, this method returns null.

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Shell object

  • BORDER - Adds a border.
  • CLOSE - Adds a close button.
  • MIN - Adds a minimize button.
  • MAX - Adds a maximize button.
  • NO_TRIM - Creates a Shell that has no border and can't be moved, closed, resized, minimized, or maximized. Not very useful, except perhaps for splash screens.
  • RESIZE - Adds a resizable border.
  • TITLE - Adds a title bar.
  • DIALOG_TRIM = TITLE | CLOSE | BORDER.
  • SHELL_TRIM = CLOSE | TITLE | MIN | MAX | RESIZE.
  • APPLICATION_MODAL - Creates a Shell that's modal to the application.
  • PRIMARY_MODAL - Creates a primary modal Shell.
  • SYSTEM_MODAL - Creates a Shell that's modal system-wide.
  • MODELESS - Creates a modeless Shell.

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Менеджеры расположения

  • FillLayout - This layout arranges components horizontally on a row or vertically on a column (BoxLayout)
  • RowLayout - Similar to FillLayout but more flexible, allowing multiple rows, fill, wrapping, and custom spacing (FlowLayout)
  • GridLayout - Lays components on a grid; offers many options for fine-grained control (GridBagLayout)
  • FormLayout - Relative layout that uses attachments to a container edge or a sibling widget's edge (Нет аналога)
  • StackLayout - Stacks components, only top component is visible (CardLayout)
  • null layout - You can place controls absolutely.

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Untyped Listeners

  • Listener interface, contains one method:
    • void handleEvent(Event event)
  • Add an untyped listener to a widget:
    • void addListener(int eventType, Listener l)
  • button.addListener(SWT.Selection, new Listener() { public void handleEvent(Event e) {
  • switch (e.type) {
  • case SWT.Selection:
  • System.out.println(“pressed");
  • break;
  • } } };

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Typed Listeners

  • ControlListener - Listens for move and resize events
  • DisposeListener - Listens for dispose events
  • FocusListener - Listens for focus gained and lost events
  • HelpListener - Listens for help requests
  • KeyListener - Listens for key presses and releases
  • MenuListener - Listens for menu events
  • ModifyListener - Listens for text modifications
  • MouseListener - Listens for mouse button presses
  • MouseMoveListener - Listens for mouse movements
  • MouseTrackListener - Listens for when the mouse enters
  • PaintListener - Listens for paint events
  • SelectionListener - Listens for selection events (for example, button clicks)
  • ShellListener - Listens for shell events
  • TraverseListener - Listens for traverse events
  • TreeListener - Listens for tree events
  • VerifyListener - Listens for, and potentially intercepts, text modifications

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  • JFace:
    • Provides Viewer classes that handle the tedious tasks of populating, sorting, filtering, and updating widgets
    • Provides Actions to allow users to define their own behavior and to assign that behavior to specific components, e.g. menu items, tool items, push buttons, etc.
    • Provides registries that hold Images and Fonts
    • Defines standard dialogs and wizards, and defines a framework for building complex interactions with the user

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  • Window: The org.eclipse.jface.window package provides window creation and management facilities. Of particular interest is the ApplicationWindow class, which provides a higher-level application window and encapsulates the SWT event loop.
  • Viewers: The org.eclipse.jface.viewers package provides a framework of viewers such as TreeViewer and TableViewer, which are model-driven components that make use of SWT widgets and adapt content of a model to the widget.
  • Dialogs: The org.eclipse.jface.dialogs package provides several commonly used dialog boxes.
  • Actions: The org.eclipse.jface.actions package provides a UI action framework that's similar

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