basicsplitpanedivider.java

gcc的组建

  {
    if (splitPaneUI != null)
      splitPaneUI.startDragging();
  }

  /**
   * Drags the divider to a given location by calling the
   * <code>dragDividerTo</code> method of the UI delegate of the enclosing
   * <code>JSplitPane</code>.
   *
   * @param location the new location of the divider.
   *
   * @see BasicSplitPaneUI#dragDividerTo(int location)
   */
  protected void dragDividerTo(int location)
  {
    if (splitPaneUI != null)
      splitPaneUI.dragDividerTo(location);
  }

  /**
   * Finishes a dragging gesture by calling the <code>finishDraggingTo</code>
   * method of the UI delegate of the enclosing <code>JSplitPane</code>.
   *
   * @param location the new, final location of the divider.
   *
   * @see BasicSplitPaneUI#finishDraggingTo(int location)
   */
  protected void finishDraggingTo(int location)
  {
    if (splitPaneUI != null)
      splitPaneUI.finishDraggingTo(location);
  }

  /**
   * This helper method moves the divider to one of the  three locations when
   * using one touch expand buttons. Location 0 is the left (or top) most
   * location. Location 1 is the middle. Location 2 is the right (or bottom)
   * most location.
   * This is package-private to avoid an accessor method.
   *
   * @param locationIndex The location to move to.
   */
  void moveDividerTo(int locationIndex)
  {
    Insets insets = splitPane.getInsets();
    switch (locationIndex)
      {
      case 1:
	splitPane.setDividerLocation(splitPane.getLastDividerLocation());
	break;
      case 0:
	int top = (orientation == JSplitPane.HORIZONTAL_SPLIT) ? insets.left
	                                                       : insets.top;
	splitPane.setDividerLocation(top);
	break;
      case 2:
	int bottom;
	if (orientation == JSplitPane.HORIZONTAL_SPLIT)
	  bottom = splitPane.getBounds().width - insets.right - dividerSize;
	else
	  bottom = splitPane.getBounds().height - insets.bottom - dividerSize;
	splitPane.setDividerLocation(bottom);
	break;
      }
  }

  /**
   * The listener for handling mouse events from both the divider and the
   * containing <code>JSplitPane</code>.
   * 
   * <p>
   * The reason for also handling MouseEvents from the containing
   * <code>JSplitPane</code> is that users should be able to start a drag
   * gesture from inside the JSplitPane, but slightly outisde the divider.
   * </p>
   *
   * @author Sascha Brawer (brawer_AT_dandelis.ch)
   */
  protected class MouseHandler extends MouseAdapter
    implements MouseMotionListener
  {
    /** Keeps track of whether a drag is occurring. */
    private transient boolean isDragging;

    /**
     * This method is called when the mouse is pressed.
     *
     * @param e The MouseEvent.
     */
    public void mousePressed(MouseEvent e)
    {
      if (splitPane.isOneTouchExpandable())
        {
	  if (e.getSource() == leftButton)
	    {
	      currentDividerLocation--;
	      if (currentDividerLocation < 0)
		currentDividerLocation = 0;
	      moveDividerTo(currentDividerLocation);
	      return;
	    }
	  else if (e.getSource() == rightButton)
	    {
	      currentDividerLocation++;
	      if (currentDividerLocation > 2)
		currentDividerLocation = 2;
	      moveDividerTo(currentDividerLocation);
	      return;
	    }
        }
      isDragging = true;
      currentDividerLocation = 1;
      if (orientation == JSplitPane.HORIZONTAL_SPLIT)
	dragger = new DragController(e);
      else
	dragger = new VerticalDragController(e);
      prepareForDragging();
    }

    /**
     * This method is called when the mouse is released.
     *
     * @param e The MouseEvent.
     */
    public void mouseReleased(MouseEvent e)
    {
      if (isDragging)
	dragger.completeDrag(e);
      isDragging = false;
    }

    /**
     * Repeatedly invoked when the user is dragging the mouse cursor while
     * having pressed a mouse button.
     *
     * @param e The MouseEvent.
     */
    public void mouseDragged(MouseEvent e)
    {
      if (dragger != null)
	dragger.continueDrag(e);
    }

    /**
     * Repeatedly invoked when the user is dragging the mouse cursor without
     * having pressed a mouse button.
     *
     * @param e The MouseEvent.
     */
    public void mouseMoved(MouseEvent e)
    {
      // Do nothing.
    }
  }

  /**
   * Performs the tasks associated with an ongoing drag operation.
   *
   * @author Sascha Brawer (brawer_AT_dandelis.ch)
   */
  protected class DragController
  {
    /**
     * The difference between where the mouse is clicked and the  initial
     * divider location.
     */
    transient int offset;

    /**
     * Creates a new DragController object.
     *
     * @param e The MouseEvent to initialize with.
     */
    protected DragController(MouseEvent e)
    {
      offset = e.getX();
    }

    /**
     * This method returns true if the divider can move.
     *
     * @return True if dragging is allowed.
     */
    protected boolean isValid()
    {
      // Views can always be resized?
      return true;
    }

    /**
     * Returns a position for the divider given the MouseEvent.
     *
     * @param e MouseEvent.
     *
     * @return The position for the divider to move to.
     */
    protected int positionForMouseEvent(MouseEvent e)
    {
      return e.getX() + getX() - offset;
    }

    /**
     * This method returns one of the two paramters for the orientation. In
     * this case, it returns x.
     *
     * @param x The x coordinate.
     * @param y The y coordinate.
     *
     * @return The x coordinate.
     */
    protected int getNeededLocation(int x, int y)
    {
      return x;
    }

    /**
     * This method is called to pass on the drag information to the UI through
     * dragDividerTo.
     *
     * @param newX The x coordinate of the MouseEvent.
     * @param newY The y coordinate of the MouseEvent.
     */
    protected void continueDrag(int newX, int newY)
    {
      if (isValid())
	dragDividerTo(adjust(newX, newY));
    }

    /**
     * This method is called to pass on the drag information  to the UI
     * through dragDividerTo.
     *
     * @param e The MouseEvent.
     */
    protected void continueDrag(MouseEvent e)
    {
      if (isValid())
	dragDividerTo(positionForMouseEvent(e));
    }

    /**
     * This method is called to finish the drag session  by calling
     * finishDraggingTo.
     *
     * @param x The x coordinate of the MouseEvent.
     * @param y The y coordinate of the MouseEvent.
     */
    protected void completeDrag(int x, int y)
    {
      finishDraggingTo(adjust(x, y));
    }

    /**
     * This method is called to finish the drag session  by calling
     * finishDraggingTo.
     *
     * @param e The MouseEvent.
     */
    protected void completeDrag(MouseEvent e)
    {
      finishDraggingTo(positionForMouseEvent(e));
    }

    /**
     * This is a helper method that includes the offset in the needed
     * location.
     *
     * @param x The x coordinate of the MouseEvent.
     * @param y The y coordinate of the MouseEvent.
     *
     * @return The needed location adjusted by the offsets.
     */
    int adjust(int x, int y)
    {
      return getNeededLocation(x, y) + getX() - offset;
    }
  }

  /**
   * This is a helper class that controls dragging when  the orientation is
   * VERTICAL_SPLIT.
   */
  protected class VerticalDragController extends DragController
  {
    /**
     * Creates a new VerticalDragController object.
     *
     * @param e The MouseEvent to initialize with.
     */
    protected VerticalDragController(MouseEvent e)
    {
      super(e);
      offset = e.getY();
    }

    /**
     * This method returns one of the two parameters given the orientation. In
     * this case, it returns y.
     *
     * @param x The x coordinate of the MouseEvent.
     * @param y The y coordinate of the MouseEvent.
     *
     * @return The y coordinate.
     */
    protected int getNeededLocation(int x, int y)
    {
      return y;
    }

    /**
     * This method returns the new location of the divider given a MouseEvent.
     *
     * @param e The MouseEvent.
     *
     * @return The new location of the divider.
     */
    protected int positionForMouseEvent(MouseEvent e)
    {
      return e.getY() + getY() - offset;
    }

    /**
     * This is a helper method that includes the offset in the needed
     * location.
     *
     * @param x The x coordinate of the MouseEvent.
     * @param y The y coordinate of the MouseEvent.
     *
     * @return The needed location adjusted by the offsets.
     */
    int adjust(int x, int y)
    {
      return getNeededLocation(x, y) + getY() - offset;
    }
  }

  /**
   * This helper class acts as the Layout Manager for the divider.
   */
  protected class DividerLayout implements LayoutManager
  {
    /**
     * Creates a new DividerLayout object.
     */
    protected DividerLayout()
    {
      // Nothing to do here.
    }

    /**
     * This method is called when a Component is added.
     *
     * @param string The constraints string.
     * @param c The Component to add.
     */
    public void addLayoutComponent(String string, Component c)
    {
      // Do nothing.
    }

    /**
     * This method is called to lay out the container.
     *
     * @param c The container to lay out.
     */
    public void layoutContainer(Container c)
    {
      if (splitPane.isOneTouchExpandable())
        {
	  changeButtonOrientation();
	  positionButtons();
        }
    }

    /**
     * This method returns the minimum layout size.
     *
     * @param c The container to calculate for.
     *
     * @return The minimum layout size.
     */
    public Dimension minimumLayoutSize(Container c)
    {
      return preferredLayoutSize(c);
    }

    /**
     * This method returns the preferred layout size.
     *
     * @param c The container to calculate for.
     *
     * @return The preferred layout size.
     */
    public Dimension preferredLayoutSize(Container c)
    {
      return new Dimension(dividerSize, dividerSize);
    }

    /**
     * This method is called when a component is removed.
     *
     * @param c The component to remove.
     */
    public void removeLayoutComponent(Component c)
    {
      // Do nothing.
    }

    /**
     * This method changes the button orientation when the orientation of the
     * SplitPane changes.
     */
    private void changeButtonOrientation()
    {
      if (orientation == JSplitPane.HORIZONTAL_SPLIT)
        {
	  ((BasicArrowButton) rightButton).setDirection(SwingConstants.EAST);
	  ((BasicArrowButton) leftButton).setDirection(SwingConstants.WEST);
        }
      else
        {
	  ((BasicArrowButton) rightButton).setDirection(SwingConstants.SOUTH);
	  ((BasicArrowButton) leftButton).setDirection(SwingConstants.NORTH);
        }
    }

    /**
     * This method sizes and positions the buttons.
     */
    private void positionButtons()
    {
      int w = 0;
      int h = 0;
      if (orientation == JSplitPane.HORIZONTAL_SPLIT)
        {
	  rightButton.setLocation(ONE_TOUCH_OFFSET, ONE_TOUCH_OFFSET);
	  leftButton.setLocation(ONE_TOUCH_OFFSET,
	                         ONE_TOUCH_OFFSET + 2 * ONE_TOUCH_SIZE);
	  w = dividerSize - 2 * ONE_TOUCH_OFFSET;
	  h = 2 * ONE_TOUCH_SIZE;
        }
      else
        {
	  leftButton.setLocation(ONE_TOUCH_OFFSET, ONE_TOUCH_OFFSET);
	  rightButton.setLocation(ONE_TOUCH_OFFSET + 2 * ONE_TOUCH_SIZE,
	                          ONE_TOUCH_OFFSET);
	  h = dividerSize - 2 * ONE_TOUCH_OFFSET;
	  w = 2 * ONE_TOUCH_SIZE;
        }
      Dimension dims = new Dimension(w, h);
      leftButton.setSize(dims);
      rightButton.setSize(dims);
    }
  }
}