Class Window

  • All Implemented Interfaces:
    IShellProvider
    Direct Known Subclasses:
    ApplicationWindow, Dialog, PopupDialog

    public abstract class Window
    extends Object
    implements IShellProvider
    A JFace window is an object that has no visual representation (no widgets) until it is told to open.

    Creating a window involves the following steps:

    • creating an instance of a concrete subclass of Window
    • creating the window's shell and widget tree by calling create (optional)
    • assigning the window to a window manager using WindowManager.add (optional)
    • opening the window by calling open

    Opening the window will create its shell and widget tree if they have not already been created. When the window is closed, the shell and widget tree are disposed of and are no longer referenced, and the window is automatically removed from its window manager. A window may be reopened.

    The JFace window framework (this package) consists of this class, Window, the abstract base of all windows, and one concrete window classes (ApplicationWindow) which may also be subclassed. Clients may define additional window subclasses as required.

    The Window class provides methods that subclasses may override to configure the window, including:

    • close- extend to free other SWT resources
    • configureShell- extend or reimplement to set shell properties before window opens
    • createContents- extend or reimplement to create controls before window opens
    • getInitialSize- reimplement to give the initial size for the shell
    • getInitialLocation- reimplement to give the initial location for the shell
    • getShellListener- extend or reimplement to receive shell events
    • handleFontChange- reimplement to respond to font changes
    • handleShellCloseEvent- extend or reimplement to handle shell closings
    • Field Detail

      • OK

        public static final int OK
        Standard return code constant (value 0) indicating that the window was opened.
        See Also:
        open(), Constant Field Values
      • CANCEL

        public static final int CANCEL
        Standard return code constant (value 1) indicating that the window was canceled.
        See Also:
        open(), Constant Field Values
      • resizeHasOccurred

        protected boolean resizeHasOccurred
        Internal fields to detect if shell size has been set
        Since:
        3.9
    • Constructor Detail

      • Window

        protected Window​(Shell parentShell)
        Creates a window instance, whose shell will be created under the given parent shell. Note that the window will have no visual representation until it is told to open. By default, open does not block.
        Parameters:
        parentShell - the parent shell, or null to create a top-level shell. Try passing "(Shell)null" to this method instead of "null" if your compiler complains about an ambiguity error.
        See Also:
        setBlockOnOpen(boolean), getDefaultOrientation()
      • Window

        protected Window​(IShellProvider shellProvider)
        Creates a new window which will create its shell as a child of whatever the given shellProvider returns.
        Parameters:
        shellProvider - object that will return the current parent shell. Not null.
        Since:
        3.1
    • Method Detail

      • canHandleShellCloseEvent

        protected boolean canHandleShellCloseEvent()
        Determines if the window should handle the close event or do nothing.

        The default implementation of this framework method returns true, which will allow the handleShellCloseEvent method to be called. Subclasses may extend or reimplement.

        Returns:
        whether the window should handle the close event.
      • close

        public boolean close()
        Closes this window, disposes its shell, and removes this window from its window manager (if it has one).

        This framework method may be extended (super.close must be called).

        Note that in order to prevent recursive calls to this method it does not call Shell#close(). As a result ShellListeners will not receive a shellClosed event.

        Returns:
        true if the window is (or was already) closed, and false if it is still open
      • configureShell

        protected void configureShell​(Shell newShell)
        Configures the given shell in preparation for opening this window in it.

        The default implementation of this framework method sets the shell's image and gives it a grid layout. Subclasses may extend or reimplement.

        Parameters:
        newShell - the shell
      • getLayout

        protected Layout getLayout()
        Creates the layout for the shell. The layout created here will be attached to the composite passed into createContents. The default implementation returns a GridLayout with no margins. Subclasses that change the layout type by overriding this method should also override createContents.

        A return value of null indicates that no layout should be attached to the composite. In this case, the layout may be attached within createContents.

        Returns:
        a newly created Layout or null if no layout should be attached.
        Since:
        3.0
      • constrainShellSize

        protected void constrainShellSize()
        Constrain the shell size to be no larger than the display bounds.
        Since:
        2.0
      • create

        public void create()
        Creates this window's widgetry in a new top-level shell.

        The default implementation of this framework method creates this window's shell (by calling createShell), and its controls (by calling createContents), then initializes this window's shell bounds (by calling initializeBounds).

      • createContents

        protected Control createContents​(Composite parent)
        Creates and returns this window's contents. Subclasses may attach any number of children to the parent. As a convenience, the return value of this method will be remembered and returned by subsequent calls to getContents(). Subclasses may modify the parent's layout if they overload getLayout() to return null.

        It is common practice to create and return a single composite that contains the entire window contents.

        The default implementation of this framework method creates an instance of Composite. Subclasses may override.

        Parameters:
        parent - the parent composite for the controls in this window. The type of layout used is determined by getLayout()
        Returns:
        the control that will be returned by subsequent calls to getContents()
      • createShell

        protected final Shell createShell()
        Creates and returns this window's shell.

        This method creates a new shell and configures it using configureShell. Subclasses should override configureShell if the shell needs to be customized.

        Returns:
        the shell
      • getContents

        protected Control getContents()
        Returns the top level control for this window. The parent of this control is the shell.
        Returns:
        the top level control, or null if this window's control has not been created yet
      • getDefaultImage

        public static Image getDefaultImage()
        Returns the default image. This is the image that will be used for windows that have no shell image at the time they are opened. There is no default image unless one is installed via setDefaultImage.
        Returns:
        the default image, or null if none
        See Also:
        setDefaultImage(org.eclipse.swt.graphics.Image)
      • getInitialLocation

        protected Point getInitialLocation​(Point initialSize)
        Returns the initial location to use for the shell. The default implementation centers the shell horizontally (1/2 of the difference to the left and 1/2 to the right) and vertically (1/3 above and 2/3 below) relative to the parent shell, or display bounds if there is no parent shell.
        Parameters:
        initialSize - the initial size of the shell, as returned by getInitialSize.
        Returns:
        the initial location of the shell
      • getInitialSize

        protected Point getInitialSize()
        Returns the initial size to use for the shell. The default implementation returns the preferred size of the shell, using Shell.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).
        Returns:
        the initial size of the shell
      • getParentShell

        protected Shell getParentShell()
        Returns parent shell, under which this window's shell is created.
        Returns:
        the parent shell, or null if there is no parent shell
      • getReturnCode

        public int getReturnCode()
        Returns this window's return code. A window's return codes are window-specific, although two standard return codes are predefined: OK and CANCEL.
        Returns:
        the return code
      • getShell

        public Shell getShell()
        Returns this window's shell.
        Specified by:
        getShell in interface IShellProvider
        Returns:
        this window's shell, or null if this window's shell has not been created yet
      • getShellListener

        protected ShellListener getShellListener()
        Returns a shell listener. This shell listener gets registered with this window's shell.

        The default implementation of this framework method returns a new listener that makes this window the active window for its window manager (if it has one) when the shell is activated, and calls the framework method handleShellCloseEvent when the shell is closed. Subclasses may extend or reimplement.

        Returns:
        a shell listener
      • getShellStyle

        protected int getShellStyle()
        Returns the shell style bits.

        The default value is SWT.CLOSE|SWT.MIN|SWT.MAX|SWT.RESIZE. Subclasses should call setShellStyle to change this value, rather than overriding this method.

        Returns:
        the shell style bits
      • getWindowManager

        public WindowManager getWindowManager()
        Returns the window manager of this window.
        Returns:
        the WindowManager, or null if none
      • handleFontChange

        protected void handleFontChange​(PropertyChangeEvent event)
        Notifies of a font property change.

        The default implementation of this framework method does nothing. Subclasses may reimplement.

        Parameters:
        event - the property change event detailing what changed
      • handleShellCloseEvent

        protected void handleShellCloseEvent()
        Notifies that the window's close button was pressed, the close menu was selected, or the ESCAPE key pressed.

        The default implementation of this framework method sets the window's return code to CANCEL and closes the window using close. Subclasses may extend or reimplement.

      • initializeBounds

        protected void initializeBounds()
        Initializes the location and size of this window's SWT shell after it has been created.

        This framework method is called by the create framework method. The default implementation calls getInitialSize and getInitialLocation and passes the results to Shell.setBounds. This is only done if the bounds of the shell have not already been modified. Subclasses may extend or reimplement.

      • open

        public int open()
        Opens this window, creating it first if it has not yet been created.

        If this window has been configured to block on open ( setBlockOnOpen), this method waits until the window is closed by the end user, and then it returns the window's return code; otherwise, this method returns immediately. A window's return codes are window-specific, although two standard return codes are predefined: OK and CANCEL.

        Returns:
        the return code
        See Also:
        create()
      • setBlockOnOpen

        public void setBlockOnOpen​(boolean shouldBlock)
        Sets whether the open method should block until the window closes.
        Parameters:
        shouldBlock - true if the open method should not return until the window closes, and false if the open method should return immediately
      • setDefaultImage

        public static void setDefaultImage​(Image image)
        Sets the default image. This is the image that will be used for windows that have no shell image at the time they are opened. There is no default image unless one is installed via this method.
        Parameters:
        image - the default image, or null if none
      • setDefaultImages

        public static void setDefaultImages​(Image[] images)
        Sets the array of default images to use for newly opened windows. It is expected that the array will contain the same icon rendered at different resolutions.
        Parameters:
        images - the array of images to be used when this window is opened
        Since:
        3.0
        See Also:
        Decorations.setImages(org.eclipse.swt.graphics.Image[])
      • setParentShell

        protected void setParentShell​(Shell newParentShell)
        Changes the parent shell. This is only safe to use when the shell is not yet realized (i.e., created). Once the shell is created, it must be disposed (i.e., closed) before this method can be called.
        Parameters:
        newParentShell - The new parent shell; this value may be null if there is to be no parent.
        Since:
        3.1
      • setReturnCode

        protected void setReturnCode​(int code)
        Sets this window's return code. The return code is automatically returned by open if block on open is enabled. For non-blocking opens, the return code needs to be retrieved manually using getReturnCode.
        Parameters:
        code - the return code
      • getConstrainedShellBounds

        protected Rectangle getConstrainedShellBounds​(Rectangle preferredSize)
        Given the desired position of the window, this method returns an adjusted position such that the window is no larger than its monitor, and does not extend beyond the edge of the monitor. This is used for computing the initial window position, and subclasses can use this as a utility method if they want to limit the region in which the window may be moved.
        Parameters:
        preferredSize - the preferred position of the window
        Returns:
        a rectangle as close as possible to preferredSize that does not extend outside the monitor
        Since:
        3.0
      • setShellStyle

        protected void setShellStyle​(int newShellStyle)
        Sets the shell style bits. This method has no effect after the shell is created.

        The shell style bits are used by the framework method createShell when creating this window's shell.

        Parameters:
        newShellStyle - the new shell style bits
      • setWindowManager

        public void setWindowManager​(WindowManager manager)
        Sets the window manager of this window.

        Note that this method is used by WindowManager to maintain a backpointer. Clients must not call the method directly.

        Parameters:
        manager - the window manager, or null if none
      • setExceptionHandler

        public static void setExceptionHandler​(Window.IExceptionHandler handler)
        Sets the exception handler for this application.

        Note that the handler may only be set once. Subsequent calls to this method will be ignored.

        Parameters:
        handler - the exception handler for the application.
      • setDefaultModalParent

        public static void setDefaultModalParent​(IShellProvider provider)
        Sets the default parent for modal Windows. This will be used to locate the parent for any modal Window constructed with a null parent.
        Parameters:
        provider - shell provider that will be used to locate the parent shell whenever a Window is created with a null parent
        Since:
        3.1
      • getDefaultOrientation

        public static int getDefaultOrientation()
        Gets the default orientation for windows. If it is not set the default value will be unspecified (SWT#NONE).
        Returns:
        SWT#NONE, SWT.RIGHT_TO_LEFT or SWT.LEFT_TO_RIGHT
        Since:
        3.1
        See Also:
        SWT.RIGHT_TO_LEFT, SWT.LEFT_TO_RIGHT, SWT.NONE
      • setDefaultOrientation

        public static void setDefaultOrientation​(int defaultOrientation)
        Sets the default orientation of windows.
        Parameters:
        defaultOrientation - one of SWT#RIGHT_TO_LEFT, SWT#LEFT_TO_RIGHT ,SWT#NONE
        Since:
        3.1
        See Also:
        SWT.RIGHT_TO_LEFT, SWT.LEFT_TO_RIGHT, SWT.NONE