ScrollPane

Name

Description

The ScrollPane class provides automatic scrolling of a child component.

Class Definition

public class java.awt.ScrollPane extends java.awt.Container {
 // Constants public final static int SCROLLBARS_ALWAYS;
public final static int SCROLLBARS_AS_NEEDED;
public final static int SCROLLBARS_NEVER; // Constructors public ScrollPane();
public ScrollPane (int scrollbarDisplayPolicy); // Public Instance Methods public void addNotify();
public void doLayout();
public Adjustable getHAdjustable();
public int getHScrollbarHeight();
public Point getScrollPosition();
public int getScrollbarDisplayPolicy();
public Adjustable getVAdjustable();
public int getVScrollbarWidth();
public Dimension getViewportSize();
public void layout();  public String paramString();
public void printComponents (Graphics g);
public final void setLayout (LayoutManager mgr);
public void setScrollPosition (int x, int y);
public void setScrollPosition (Point p); //Protected Instance Methods protected final void addImpl (Component comp, Object constraints, int index);
}

Constants

SCROLLBARS_ALWAYS

public final static int SCROLLBARS_ALWAYS

Always show the scrollbars.

SCROLLBARS_AS_NEEDED

public final static int SCROLLBARS_AS_NEEDED

Only show the scrollbars if the contents of the ScrollPane are larger than what is visible.

SCROLLBARS_NEVER

public final static int SCROLLBARS_NEVER

Don't ever show the scrollbars. The ScrollPane can still be scrolled programmatically.

Constructors

ScrollPane

public ScrollPane()

• Description
• Constructs a ScrollPane object with SCROLLBARS_AS_NEEDED.

public ScrollPane (int scrollbarDisplayPolicy)

• Parameters
• • scrollbarDisplayPolicy
  • One of the SCROLLBARS_ constants.
• Description
• Constructs a ScrollPane object with the specified scrollbar display policy.

Instance Methods

addImpl

protected final void addImpl (Component comp, Object constraints, int index)

• Parameters
• • comp
  • The component to add to the Scrollpane.
  • constraints
  • Layout constraints; ignored.
  • index
  • The position at which to add the component; should always be less than or equal to 0.
• Returns
• The component that was added.
• Overrides
• Container.addImpl (Component, Object, int)
• Throws
• • IllegalArgumentException
  • If pos is greater than 0.
• Description
• Adds a child component to the Scrollpane. If there already was a child component, it is replaced by the new component.

addNotify

public void addNotify()

• Overrides
• Container.addNotify()
• Description
• Creates ScrollPane's peer.

doLayout

public void doLayout()

• Overrides
• Container.doLayout()
• Description
• Lays out the ScrollPane. Resizes the child component to its preferred size.

getHAdjustable

public Adjustable getHAdjustable()

• Returns
• The object implementing the Adjustable interface that is used to adjust the ScrollPane horizontally. Usually this is a Scrollbar.

getHScrollbarHeight

public int getHScrollbarHeight()

• Returns
• The height a horizontal scrollbar would occupy, regardless of whether it's shown or not.

getScrollPosition

public Point getScrollPosition()

• Returns
• Returns the position within the child component that is displayed at 0, 0 in the ScrollPane.

getScrollbarDisplayPolicy

public int getScrollbarDisplayPolicy()

• Returns
• The display policy for the scrollbars (one of the SCROLLBARS_ constants).

getVAdjustable

public Adjustable getVAdjustable()

• Returns
• The object implementing the Adjustable interface that is used to adjust the ScrollPane vertically. Usually this is a Scrollbar.

getVScrollbarWidth

public int getVScrollbarWidth()

• Returns
• The width a vertical scrollbar would occupy, regardless of whether it's shown or not.

getViewportSize

public Dimension getViewportSize()

• Returns
• The size of the ScrollPane's port (the area of the child component that is shown).

layout

public void layout()

• Overrides
• Container.layout()
• Description
• Lays out component. Replaced by doLayout().

paramString

public String paramString()

• Returns
• String with current settings of ScrollPane.
• Overrides
• Container.paramString()
• Description
• Helper method for toString() to generate string of current settings.

printComponents

public void printComponents (Graphics g)

• Parameters
• • g
  • Graphics context.
• Overrides
• Container.printComponents(Graphics)
• Description
• Prints the ScrollPane's child component.

setLayout

public void setLayout (LayoutManager manager)

• Parameters
• • manager
  • Ignored.
• Overrides
• Container.setLayout(LayoutManager)
• Description
• Does nothing. No layout manager is needed because there is only one child component.

setScrollPosition

public void setScrollPosition (int x, int y)

• Parameters
• • x
  • New horizontal position.
  • y
  • New vertical position.
• Throws
• • IllegalArgumentException
  • If the point given is not valid.
• Description
• Scroll to the given position in the child component.

public void setScrollPosition (Point p)

• Parameters
• • p
  • New position.
• Throws
• • IllegalArgumentException
  • If the point given is not valid.
• Description
• Scroll to the given position in the child component.

See Also

Adjustable, Container, Point, Scrollbar