Class Slider

  • All Implemented Interfaces:
    Drawable

    public class Slider
    extends Control
    Instances of this class are selectable user interface objects that represent a range of positive, numeric values.

    At any given moment, a given slider will have a single 'selection' that is considered to be its value, which is constrained to be within the range of values the slider represents (that is, between its minimum and maximum values).

    Typically, sliders will be made up of five areas:

    1. an arrow button for decrementing the value
    2. a page decrement area for decrementing the value by a larger amount
    3. a thumb for modifying the value by mouse dragging
    4. a page increment area for incrementing the value by a larger amount
    5. an arrow button for incrementing the value

    Based on their style, sliders are either HORIZONTAL (which have a left facing button for decrementing the value and a right facing button for incrementing it) or VERTICAL (which have an upward facing button for decrementing the value and a downward facing buttons for incrementing it).

    On some platforms, the size of the slider's thumb can be varied relative to the magnitude of the range of values it represents (that is, relative to the difference between its maximum and minimum values). Typically, this is used to indicate some proportional value such as the ratio of the visible area of a document to the total amount of space that it would take to display it. SWT supports setting the thumb size even if the underlying platform does not, but in this case the appearance of the slider will not change.

    Styles:
    HORIZONTAL, VERTICAL
    Events:
    Selection

    Note: Only one of the styles HORIZONTAL and VERTICAL may be specified.

    IMPORTANT: This class is not intended to be subclassed.

    See Also:
    ScrollBar, Slider snippets, SWT Example: ControlExample, Sample code and further information
    Restriction:
    This class is not intended to be subclassed by clients.
    • Constructor Detail

      • Slider

        public Slider​(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 composite control which will be the parent of the new instance (cannot be null)
        style - the style of control 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
        • ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass
        See Also:
        SWT.HORIZONTAL, SWT.VERTICAL, Widget.checkSubclass(), Widget.getStyle()
    • Method Detail

      • addSelectionListener

        public void addSelectionListener​(SelectionListener listener)
        Adds the listener to the collection of listeners who will be notified when the user changes the receiver's value, by sending it one of the messages defined in the SelectionListener interface.

        When widgetSelected is called, the event object detail field contains one of the following values: SWT.NONE - for the end of a drag. SWT.DRAG. SWT.HOME. SWT.END. SWT.ARROW_DOWN. SWT.ARROW_UP. SWT.PAGE_DOWN. SWT.PAGE_UP. widgetDefaultSelected is not called.

        Parameters:
        listener - the listener which should be notified when the user changes the receiver's value
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        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:
        SelectionListener, removeSelectionListener(org.eclipse.swt.events.SelectionListener), SelectionEvent
      • getEnabled

        public boolean getEnabled()
        Description copied from class: Control
        Returns true if the receiver is enabled, and false otherwise. A disabled control is typically not selectable from the user interface and draws with an inactive or "grayed" look.
        Overrides:
        getEnabled in class Control
        Returns:
        the receiver's enabled state
        See Also:
        Control.isEnabled()
      • getIncrement

        public int getIncrement()
        Returns the amount that the receiver's value will be modified by when the up/down (or right/left) arrows are pressed.
        Returns:
        the increment
        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
      • getMaximum

        public int getMaximum()
        Returns the maximum value which the receiver will allow.
        Returns:
        the maximum
        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
      • getMinimum

        public int getMinimum()
        Returns the minimum value which the receiver will allow.
        Returns:
        the minimum
        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
      • getPageIncrement

        public int getPageIncrement()
        Returns the amount that the receiver's value will be modified by when the page increment/decrement areas are selected.
        Returns:
        the page increment
        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
      • getSelection

        public int getSelection()
        Returns the 'selection', which is the receiver's value.
        Returns:
        the selection
        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
      • getThumb

        public int getThumb()
        Returns the receiver's thumb value.
        Returns:
        the thumb value
        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
      • setIncrement

        public void setIncrement​(int value)
        Sets the amount that the receiver's value will be modified by when the up/down (or right/left) arrows are pressed to the argument, which must be at least one.
        Parameters:
        value - the new increment (must be greater than zero)
        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
      • setMaximum

        public void setMaximum​(int value)
        Sets the maximum. If this value is negative or less than or equal to the minimum, the value is ignored. If necessary, first the thumb and then the selection are adjusted to fit within the new range.
        Parameters:
        value - the new maximum, which must be greater than the current minimum
        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
      • setMinimum

        public void setMinimum​(int value)
        Sets the minimum value. If this value is negative or greater than or equal to the maximum, the value is ignored. If necessary, first the thumb and then the selection are adjusted to fit within the new range.
        Parameters:
        value - the new minimum
        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
      • setPageIncrement

        public void setPageIncrement​(int value)
        Sets the amount that the receiver's value will be modified by when the page increment/decrement areas are selected to the argument, which must be at least one.
        Parameters:
        value - the page increment (must be greater than zero)
        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
      • setSelection

        public void setSelection​(int value)
        Sets the 'selection', which is the receiver's value, to the argument which must be greater than or equal to zero.
        Parameters:
        value - the new selection (must be zero or greater)
        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
      • setThumb

        public void setThumb​(int value)
        Sets the thumb value. The thumb value should be used to represent the size of the visual portion of the current range. This value is usually the same as the page increment value.

        This new value will be ignored if it is less than one, and will be clamped if it exceeds the receiver's current range.

        Parameters:
        value - the new thumb value, which must be at least one and not larger than the size of the current range
        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
      • setValues

        public void setValues​(int selection,
                              int minimum,
                              int maximum,
                              int thumb,
                              int increment,
                              int pageIncrement)
        Sets the receiver's selection, minimum value, maximum value, thumb, increment and page increment all at once.

        Note: This is similar to setting the values individually using the appropriate methods, but may be implemented in a more efficient fashion on some platforms.

        Parameters:
        selection - the new selection value
        minimum - the new minimum value
        maximum - the new maximum value
        thumb - the new thumb value
        increment - the new increment value
        pageIncrement - the new pageIncrement value
        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