Class Composite

    • Constructor Detail

      • Composite

        public Composite​(Composite parent,
                         int style)
        Constructs a new instance of this class given its parent and a style value describing its behavior and appearance.

        The style value is either one of the style constants defined in class SWT which is applicable to instances of this class, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those SWT style constants. The class description lists the style constants that are applicable to the class. Style bits are also inherited from superclasses.

        Parameters:
        parent - a widget which will be the parent of the new instance (cannot be null)
        style - the style of widget to construct
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the parent is null
        SWTException -
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
        See Also:
        SWT.NO_BACKGROUND, SWT.NO_FOCUS, SWT.NO_MERGE_PAINTS, SWT.NO_REDRAW_RESIZE, SWT.NO_RADIO_GROUP, SWT.EMBEDDED, SWT.DOUBLE_BUFFERED, Widget.getStyle()
    • Method Detail

      • changed

        @Deprecated
        public void changed​(Control[] changed)
        Deprecated.
        Clears any data that has been cached by a Layout for all widgets that are in the parent hierarchy of the changed control up to and including the receiver. If an ancestor does not have a layout, it is skipped.
        Parameters:
        changed - an array of controls that changed state and require a recalculation of size
        Throws:
        IllegalArgumentException -
        • ERROR_INVALID_ARGUMENT - if the changed array is null any of its controls are null or have been disposed
        • ERROR_INVALID_PARENT - if any control in changed is not in the widget tree of the receiver
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.1
      • checkSubclass

        protected void checkSubclass()
        Description copied from class: Widget
        Checks that this class can be subclassed.

        The SWT class library is intended to be subclassed only at specific, controlled points (most notably, Composite and Canvas when implementing new widgets). This method enforces this rule unless it is overridden.

        IMPORTANT: By providing an implementation of this method that allows a subclass of a class which does not normally allow subclassing to be created, the implementer agrees to be fully responsible for the fact that any such subclass will likely fail between SWT releases and will be strongly platform specific. No support is provided for user-written classes which are implemented in this fashion.

        The ability to subclass outside of the allowed SWT classes is intended purely to enable those not on the SWT development team to implement patches in order to get around specific limitations in advance of when those limitations can be addressed by the team. Subclassing should not be attempted without an intimate and detailed understanding of the hierarchy.

        Overrides:
        checkSubclass in class Widget
      • drawBackground

        public void drawBackground​(GC gc,
                                   int x,
                                   int y,
                                   int width,
                                   int height,
                                   int offsetX,
                                   int offsetY)
        Fills the interior of the rectangle specified by the arguments, with the receiver's background.

        The offsetX and offsetY are used to map from the gc origin to the origin of the parent image background. This is useful to ensure proper alignment of the image background.

        Parameters:
        gc - the gc where the rectangle is to be filled
        x - the x coordinate of the rectangle to be filled
        y - the y coordinate of the rectangle to be filled
        width - the width of the rectangle to be filled
        height - the height of the rectangle to be filled
        offsetX - the image background x offset
        offsetY - the image background y offset
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the gc is null
        • ERROR_INVALID_ARGUMENT - if the gc has been disposed
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.6
      • getBackgroundMode

        public int getBackgroundMode()
        Returns the receiver's background drawing mode. This will be one of the following constants defined in class SWT: INHERIT_NONE, INHERIT_DEFAULT, INHERIT_FORCE.
        Returns:
        the background mode
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.2
        See Also:
        SWT
      • getChildren

        public Control[] getChildren()
        Returns a (possibly empty) array containing the receiver's children. Children are returned in the order that they are drawn. The topmost control appears at the beginning of the array. Subsequent controls draw beneath this control and appear later in the array.

        Note: This is not the actual structure used by the receiver to maintain its list of children, so modifying the array will not affect the receiver.

        Returns:
        an array of children
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        Control.moveAbove(org.eclipse.swt.widgets.Control), Control.moveBelow(org.eclipse.swt.widgets.Control)
      • getLayout

        public Layout getLayout()
        Returns layout which is associated with the receiver, or null if one has not been set.
        Returns:
        the receiver's layout or null
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
      • getTabList

        public Control[] getTabList()
        Gets the (possibly empty) tabbing order for the control.
        Returns:
        tabList the ordered list of controls representing the tab order
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        setTabList(org.eclipse.swt.widgets.Control[])
      • getLayoutDeferred

        public boolean getLayoutDeferred()
        Returns true if the receiver has deferred the performing of layout, and false otherwise.
        Returns:
        the receiver's deferred layout state
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.1
        See Also:
        setLayoutDeferred(boolean), isLayoutDeferred()
      • isLayoutDeferred

        public boolean isLayoutDeferred()
        Returns true if the receiver or any ancestor up to and including the receiver's nearest ancestor shell has deferred the performing of layouts. Otherwise, false is returned.
        Returns:
        the receiver's deferred layout state
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.1
        See Also:
        setLayoutDeferred(boolean), getLayoutDeferred()
      • layout

        public void layout()
        If the receiver has a layout, asks the layout to lay out (that is, set the size and location of) the receiver's children. If the receiver does not have a layout, do nothing.

        Use of this method is discouraged since it is the least-efficient way to trigger a layout. The use of layout(true) discards all cached layout information, even from controls which have not changed. It is much more efficient to invoke Control.requestLayout() on every control which has changed in the layout than it is to invoke this method on the layout itself.

        This is equivalent to calling layout(true).

        Note: Layout is different from painting. If a child is moved or resized such that an area in the parent is exposed, then the parent will paint. If no child is affected, the parent will not paint.

        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
      • layout

        public void layout​(boolean changed)
        If the receiver has a layout, asks the layout to lay out (that is, set the size and location of) the receiver's children. If the argument is true the layout must not rely on any information it has cached about the immediate children. If it is false the layout may (potentially) optimize the work it is doing by assuming that none of the receiver's children has changed state since the last layout. If the receiver does not have a layout, do nothing.

        It is normally more efficient to invoke Control.requestLayout() on every control which has changed in the layout than it is to invoke this method on the layout itself. Clients are encouraged to use Control.requestLayout() where possible instead of calling this method.

        If a child is resized as a result of a call to layout, the resize event will invoke the layout of the child. The layout will cascade down through all child widgets in the receiver's widget tree until a child is encountered that does not resize. Note that a layout due to a resize will not flush any cached information (same as layout(false)).

        Note: Layout is different from painting. If a child is moved or resized such that an area in the parent is exposed, then the parent will paint. If no child is affected, the parent will not paint.

        Parameters:
        changed - true if the layout must flush its caches, and false otherwise
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
      • layout

        public void layout​(boolean changed,
                           boolean all)
        If the receiver has a layout, asks the layout to lay out (that is, set the size and location of) the receiver's children. If the changed argument is true the layout must not rely on any information it has cached about its children. If it is false the layout may (potentially) optimize the work it is doing by assuming that none of the receiver's children has changed state since the last layout. If the all argument is true the layout will cascade down through all child widgets in the receiver's widget tree, regardless of whether the child has changed size. The changed argument is applied to all layouts. If the all argument is false, the layout will not cascade down through all child widgets in the receiver's widget tree. However, if a child is resized as a result of a call to layout, the resize event will invoke the layout of the child. Note that a layout due to a resize will not flush any cached information (same as layout(false)).

        It is normally more efficient to invoke Control.requestLayout() on every control which has changed in the layout than it is to invoke this method on the layout itself. Clients are encouraged to use Control.requestLayout() where possible instead of calling this method.

        Note: Layout is different from painting. If a child is moved or resized such that an area in the parent is exposed, then the parent will paint. If no child is affected, the parent will not paint.

        Parameters:
        changed - true if the layout must flush its caches, and false otherwise
        all - true if all children in the receiver's widget tree should be laid out, and false otherwise
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.1
      • layout

        public void layout​(Control[] changed)
        Forces a lay out (that is, sets the size and location) of all widgets that are in the parent hierarchy of the changed control up to and including the receiver. The layouts in the hierarchy must not rely on any information cached about the changed control or any of its ancestors. The layout may (potentially) optimize the work it is doing by assuming that none of the peers of the changed control have changed state since the last layout. If an ancestor does not have a layout, skip it.

        It is normally more efficient to invoke Control.requestLayout() on every control which has changed in the layout than it is to invoke this method on the layout itself. Clients are encouraged to use Control.requestLayout() where possible instead of calling this method.

        Note: Layout is different from painting. If a child is moved or resized such that an area in the parent is exposed, then the parent will paint. If no child is affected, the parent will not paint.

        Parameters:
        changed - a control that has had a state change which requires a recalculation of its size
        Throws:
        IllegalArgumentException -
        • ERROR_INVALID_ARGUMENT - if the changed array is null any of its controls are null or have been disposed
        • ERROR_INVALID_PARENT - if any control in changed is not in the widget tree of the receiver
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.1
      • layout

        public void layout​(Control[] changed,
                           int flags)
        Forces a lay out (that is, sets the size and location) of all widgets that are in the parent hierarchy of the changed control up to and including the receiver.

        The parameter flags may be a combination of:

        SWT.ALL
        all children in the receiver's widget tree should be laid out
        SWT.CHANGED
        the layout must flush its caches
        SWT.DEFER
        layout will be deferred

        When the changed array is specified, the flags SWT.ALL and SWT.CHANGED have no effect. In this case, the layouts in the hierarchy must not rely on any information cached about the changed control or any of its ancestors. The layout may (potentially) optimize the work it is doing by assuming that none of the peers of the changed control have changed state since the last layout. If an ancestor does not have a layout, skip it.

        When the changed array is not specified, the flag SWT.ALL indicates that the whole widget tree should be laid out. And the flag SWT.CHANGED indicates that the layouts should flush any cached information for all controls that are laid out.

        The SWT.DEFER flag always causes the layout to be deferred by calling Composite.setLayoutDeferred(true) and scheduling a call to Composite.setLayoutDeferred(false), which will happen when appropriate (usually before the next event is handled). When this flag is set, the application should not call Composite.setLayoutDeferred(boolean).

        Note: Layout is different from painting. If a child is moved or resized such that an area in the parent is exposed, then the parent will paint. If no child is affected, the parent will not paint.

        Parameters:
        changed - a control that has had a state change which requires a recalculation of its size
        flags - the flags specifying how the layout should happen
        Throws:
        IllegalArgumentException -
        • ERROR_INVALID_ARGUMENT - if any of the controls in changed is null or has been disposed
        • ERROR_INVALID_PARENT - if any control in changed is not in the widget tree of the receiver
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.6
      • setBackgroundMode

        public void setBackgroundMode​(int mode)
        Sets the background drawing mode to the argument which should be one of the following constants defined in class SWT: INHERIT_NONE, INHERIT_DEFAULT, INHERIT_FORCE.
        Parameters:
        mode - the new background mode
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.2
        See Also:
        SWT
      • setFocus

        public boolean setFocus()
        Description copied from class: Control
        Causes the receiver to have the keyboard focus, such that all keyboard events will be delivered to it. Focus reassignment will respect applicable platform constraints.
        Overrides:
        setFocus in class Control
        Returns:
        true if the control got focus, and false if it was unable to.
        See Also:
        Control.forceFocus()
      • setLayout

        public void setLayout​(Layout layout)
        Sets the layout which is associated with the receiver to be the argument which may be null.
        Parameters:
        layout - the receiver's new layout or null
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
      • setLayoutDeferred

        public void setLayoutDeferred​(boolean defer)
        If the argument is true, causes subsequent layout operations in the receiver or any of its children to be ignored. No layout of any kind can occur in the receiver or any of its children until the flag is set to false. Layout operations that occurred while the flag was true are remembered and when the flag is set to false, the layout operations are performed in an optimized manner. Nested calls to this method are stacked.
        Parameters:
        defer - the new defer state
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        3.1
        See Also:
        layout(boolean), layout(Control[])
      • setTabList

        public void setTabList​(Control[] tabList)
        Sets the tabbing order for the specified controls to match the order that they occur in the argument list.
        Parameters:
        tabList - the ordered list of controls representing the tab order or null
        Throws:
        IllegalArgumentException -
        • ERROR_INVALID_ARGUMENT - if a widget in the tabList is null or has been disposed
        • ERROR_INVALID_PARENT - if widget in the tabList is not in the same widget tree
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver