Class Scrollbar

public Scrollbar()
          throws HeadlessException

public Scrollbar(int orientation)
          throws HeadlessException

Constructs a new scroll bar with the specified orientation.

The orientation argument must take one of the two values Scrollbar.HORIZONTAL, or Scrollbar.VERTICAL, indicating a horizontal or vertical scroll bar, respectively.

public Scrollbar(int orientation,
                 int value,
                 int visible,
                 int minimum,
                 int maximum)
          throws HeadlessException

Constructs a new scroll bar with the specified orientation, initial value, visible amount, and minimum and maximum values.

The orientation argument must take one of the two values Scrollbar.HORIZONTAL, or Scrollbar.VERTICAL, indicating a horizontal or vertical scroll bar, respectively.

The parameters supplied to this constructor are subject to the constraints described in setValues(int, int, int, int).

public void addNotify()

public int getOrientation()

public void setOrientation(int orientation)

public int getValue()

public void setValue(int newValue)

Sets the value of this scroll bar to the specified value.

If the value supplied is less than the current minimum or greater than the current maximum - visibleAmount, then either minimum or maximum - visibleAmount is substituted, as appropriate.

Normally, a program should change a scroll bar's value only by calling setValues. The setValues method simultaneously and synchronously sets the minimum, maximum, visible amount, and value properties of a scroll bar, so that they are mutually consistent.

Calling this method does not fire an AdjustmentEvent.

public int getMinimum()

public void setMinimum(int newMinimum)

Sets the minimum value of this scroll bar.

When setMinimum is called, the minimum value is changed, and other values (including the maximum, the visible amount, and the current scroll bar value) are changed to be consistent with the new minimum.

Normally, a program should change a scroll bar's minimum value only by calling setValues. The setValues method simultaneously and synchronously sets the minimum, maximum, visible amount, and value properties of a scroll bar, so that they are mutually consistent.

Note that setting the minimum value to Integer.MAX_VALUE will result in the new minimum value being set to Integer.MAX_VALUE - 1.

public int getMaximum()

public void setMaximum(int newMaximum)

Sets the maximum value of this scroll bar.

When setMaximum is called, the maximum value is changed, and other values (including the minimum, the visible amount, and the current scroll bar value) are changed to be consistent with the new maximum.

Normally, a program should change a scroll bar's maximum value only by calling setValues. The setValues method simultaneously and synchronously sets the minimum, maximum, visible amount, and value properties of a scroll bar, so that they are mutually consistent.

Note that setting the maximum value to Integer.MIN_VALUE will result in the new maximum value being set to Integer.MIN_VALUE + 1.

public int getVisibleAmount()

Gets the visible amount of this scroll bar.

When a scroll bar is used to select a range of values, the visible amount is used to represent the range of values that are currently visible. The size of the scroll bar's bubble (also called a thumb or scroll box), usually gives a visual representation of the relationship of the visible amount to the range of the scroll bar. Note that depending on platform, the value of the visible amount property may not be visually indicated by the size of the bubble.

The scroll bar's bubble may not be displayed when it is not moveable (e.g. when it takes up the entire length of the scroll bar's track, or when the scroll bar is disabled). Whether the bubble is displayed or not will not affect the value returned by getVisibleAmount.

@Deprecated
public int getVisible()

Deprecated.

public void setVisibleAmount(int newAmount)

Sets the visible amount of this scroll bar.

When a scroll bar is used to select a range of values, the visible amount is used to represent the range of values that are currently visible. The size of the scroll bar's bubble (also called a thumb or scroll box), usually gives a visual representation of the relationship of the visible amount to the range of the scroll bar. Note that depending on platform, the value of the visible amount property may not be visually indicated by the size of the bubble.

The scroll bar's bubble may not be displayed when it is not moveable (e.g. when it takes up the entire length of the scroll bar's track, or when the scroll bar is disabled). Whether the bubble is displayed or not will not affect the value returned by getVisibleAmount.

If the visible amount supplied is less than one or greater than the current maximum - minimum, then either one or maximum - minimum is substituted, as appropriate.

Normally, a program should change a scroll bar's value only by calling setValues. The setValues method simultaneously and synchronously sets the minimum, maximum, visible amount, and value properties of a scroll bar, so that they are mutually consistent.

public void setUnitIncrement(int v)

Sets the unit increment for this scroll bar.

The unit increment is the value that is added or subtracted when the user activates the unit increment area of the scroll bar, generally through a mouse or keyboard gesture that the scroll bar receives as an adjustment event. The unit increment must be greater than zero. Attempts to set the unit increment to a value lower than 1 will result in a value of 1 being set.

In some operating systems, this property can be ignored by the underlying controls.

@Deprecated
public void setLineIncrement(int v)

Deprecated.

public int getUnitIncrement()

Gets the unit increment for this scrollbar.

The unit increment is the value that is added or subtracted when the user activates the unit increment area of the scroll bar, generally through a mouse or keyboard gesture that the scroll bar receives as an adjustment event. The unit increment must be greater than zero.

In some operating systems, this property can be ignored by the underlying controls.

@Deprecated
public int getLineIncrement()

Deprecated.

public void setBlockIncrement(int v)

Sets the block increment for this scroll bar.

The block increment is the value that is added or subtracted when the user activates the block increment area of the scroll bar, generally through a mouse or keyboard gesture that the scroll bar receives as an adjustment event. The block increment must be greater than zero. Attempts to set the block increment to a value lower than 1 will result in a value of 1 being set.

@Deprecated
public void setPageIncrement(int v)

Deprecated.

public int getBlockIncrement()

Gets the block increment of this scroll bar.

The block increment is the value that is added or subtracted when the user activates the block increment area of the scroll bar, generally through a mouse or keyboard gesture that the scroll bar receives as an adjustment event. The block increment must be greater than zero.

@Deprecated
public int getPageIncrement()

Deprecated.

public void setValues(int value,
                      int visible,
                      int minimum,
                      int maximum)

Sets the values of four properties for this scroll bar: value, visibleAmount, minimum, and maximum. If the values supplied for these properties are inconsistent or incorrect, they will be changed to ensure consistency.

This method simultaneously and synchronously sets the values of four scroll bar properties, assuring that the values of these properties are mutually consistent. It enforces the following constraints: maximum must be greater than minimum, maximum - minimum must not be greater than Integer.MAX_VALUE, visibleAmount must be greater than zero. visibleAmount must not be greater than maximum - minimum, value must not be less than minimum, and value must not be greater than maximum - visibleAmount

Calling this method does not fire an AdjustmentEvent.

public boolean getValueIsAdjusting()

public void setValueIsAdjusting(boolean b)

public void addAdjustmentListener(AdjustmentListener l)

Adds the specified adjustment listener to receive instances of AdjustmentEvent from this scroll bar. If l is null, no exception is thrown and no action is performed.

Refer to AWT Threading Issues for details on AWT's threading model.

public void removeAdjustmentListener(AdjustmentListener l)

Removes the specified adjustment listener so that it no longer receives instances of AdjustmentEvent from this scroll bar. If l is null, no exception is thrown and no action is performed.

Refer to AWT Threading Issues for details on AWT's threading model.

public AdjustmentListener[] getAdjustmentListeners()

public <T extends EventListener> T[] getListeners(Class<T> listenerType)

Returns an array of all the objects currently registered as FooListeners upon this Scrollbar. FooListeners are registered using the addFooListener method.

You can specify the listenerType argument with a class literal, such as FooListener.class. For example, you can query a Scrollbar c for its mouse listeners with the following code:

MouseListener[] mls = (MouseListener[])(c.getListeners(MouseListener.class));

If no such listeners exist, this method returns an empty array.

protected void processEvent(AWTEvent e)

Processes events on this scroll bar. If the event is an instance of AdjustmentEvent, it invokes the processAdjustmentEvent method. Otherwise, it invokes its superclass's processEvent method.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.

protected void processAdjustmentEvent(AdjustmentEvent e)

Processes adjustment events occurring on this scrollbar by dispatching them to any registered AdjustmentListener objects.

This method is not called unless adjustment events are enabled for this component. Adjustment events are enabled when one of the following occurs:

• An AdjustmentListener object is registered via addAdjustmentListener.
• Adjustment events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.

protected String paramString()

public AccessibleContext getAccessibleContext()