basicsliderui.java

java1.6众多例子参考

        * then reduce the scrollbars value by one page ("page up"), 
        * otherwise increase it by one page.  If there is no 
        * thumb then page up if the mouse is in the upper half
        * of the track.
        */
        public void mousePressed(MouseEvent e) {
            if (!slider.isEnabled()) {
                return;
            }

            currentMouseX = e.getX();
            currentMouseY = e.getY();

            if (slider.isRequestFocusEnabled()) {
                slider.requestFocus();
            }

            // Clicked in the Thumb area?
            if (thumbRect.contains(currentMouseX, currentMouseY)) {
                switch (slider.getOrientation()) {
                case JSlider.VERTICAL:
                    offset = currentMouseY - thumbRect.y;
                    break;
                case JSlider.HORIZONTAL:
                    offset = currentMouseX - thumbRect.x;
                    break;
                }
                isDragging = true;
                return;
            }
            isDragging = false;
            slider.setValueIsAdjusting(true);

            Dimension sbSize = slider.getSize();
            int direction = POSITIVE_SCROLL;

            switch (slider.getOrientation()) {
            case JSlider.VERTICAL:
                if ( thumbRect.isEmpty() ) {
                    int scrollbarCenter = sbSize.height / 2;
                    if ( !drawInverted() ) {
                        direction = (currentMouseY < scrollbarCenter) ?
                            POSITIVE_SCROLL : NEGATIVE_SCROLL;
                    }
                    else {
                        direction = (currentMouseY < scrollbarCenter) ?
                            NEGATIVE_SCROLL : POSITIVE_SCROLL;
                    }
                }
                else {
                    int thumbY = thumbRect.y;
                    if ( !drawInverted() ) {
                        direction = (currentMouseY < thumbY) ?
                            POSITIVE_SCROLL : NEGATIVE_SCROLL;
                    }
                    else {
                        direction = (currentMouseY < thumbY) ?
                            NEGATIVE_SCROLL : POSITIVE_SCROLL;
                    }
                }
                break;                    
            case JSlider.HORIZONTAL:
                if ( thumbRect.isEmpty() ) {
                    int scrollbarCenter = sbSize.width / 2;
                    if ( !drawInverted() ) {
                        direction = (currentMouseX < scrollbarCenter) ?
                            NEGATIVE_SCROLL : POSITIVE_SCROLL;
                    }
                    else {
                        direction = (currentMouseX < scrollbarCenter) ?
                            POSITIVE_SCROLL : NEGATIVE_SCROLL;
                    }
                }
                else {
                    int thumbX = thumbRect.x;
                    if ( !drawInverted() ) {
                        direction = (currentMouseX < thumbX) ?
                            NEGATIVE_SCROLL : POSITIVE_SCROLL;
                    }
                    else {
                        direction = (currentMouseX < thumbX) ?
                            POSITIVE_SCROLL : NEGATIVE_SCROLL;
                    }
                }
                break;
            }

	    if (shouldScroll(direction)) {
		scrollDueToClickInTrack(direction);
	    }
	    if (shouldScroll(direction)) {
		scrollTimer.stop();
		scrollListener.setDirection(direction);
		scrollTimer.start();
	    }
        }

        public boolean shouldScroll(int direction) {
            Rectangle r = thumbRect;
            if (slider.getOrientation() == JSlider.VERTICAL) {
                if (drawInverted() ? direction < 0 : direction > 0) {
                    if (r.y  <= currentMouseY) {
                        return false;
                    }
                }
                else if (r.y + r.height >= currentMouseY) {
                    return false;
                }
            }
            else {
                if (drawInverted() ? direction < 0 : direction > 0) {
                    if (r.x + r.width  >= currentMouseX) {
                        return false;
                    }
                }
                else if (r.x <= currentMouseX) {
                    return false;
                }
            }

            if (direction > 0 && slider.getValue() + slider.getExtent() >=
                    slider.getMaximum()) {
                return false;
            }
            else if (direction < 0 && slider.getValue() <=
                    slider.getMinimum()) {
                return false;
            }

            return true;
        }

        /** 
        * Set the models value to the position of the top/left
        * of the thumb relative to the origin of the track.
        */
        public void mouseDragged(MouseEvent e) {
            int thumbMiddle = 0;

            if (!slider.isEnabled()) {
                return;
            }

            currentMouseX = e.getX();
            currentMouseY = e.getY();

            if (!isDragging) {
                return;
            }

            slider.setValueIsAdjusting(true);

            switch (slider.getOrientation()) {
            case JSlider.VERTICAL:      
                int halfThumbHeight = thumbRect.height / 2;
                int thumbTop = e.getY() - offset;
                int trackTop = trackRect.y;
                int trackBottom = trackRect.y + (trackRect.height - 1);
                int vMax = yPositionForValue(slider.getMaximum() -
                                            slider.getExtent());

                if (drawInverted()) {
                    trackBottom = vMax;
                }
                else {
                    trackTop = vMax;
                }
                thumbTop = Math.max(thumbTop, trackTop - halfThumbHeight);
                thumbTop = Math.min(thumbTop, trackBottom - halfThumbHeight);

                setThumbLocation(thumbRect.x, thumbTop);

                thumbMiddle = thumbTop + halfThumbHeight;
                slider.setValue( valueForYPosition( thumbMiddle ) );
                break;
            case JSlider.HORIZONTAL:
                int halfThumbWidth = thumbRect.width / 2;
                int thumbLeft = e.getX() - offset;
                int trackLeft = trackRect.x;
                int trackRight = trackRect.x + (trackRect.width - 1);
                int hMax = xPositionForValue(slider.getMaximum() -
                                            slider.getExtent());

                if (drawInverted()) {
                    trackLeft = hMax;
                }
                else {
                    trackRight = hMax;
                }
                thumbLeft = Math.max(thumbLeft, trackLeft - halfThumbWidth);
                thumbLeft = Math.min(thumbLeft, trackRight - halfThumbWidth);

                setThumbLocation(thumbLeft, thumbRect.y);

                thumbMiddle = thumbLeft + halfThumbWidth;
                slider.setValue(valueForXPosition(thumbMiddle));
                break;
            default:
                return;
            }
        }

        public void mouseMoved(MouseEvent e) { }
    }

    /**
     * Scroll-event listener.
     *
     * This class should be treated as a &quot;protected&quot; inner class.
     * Instantiate it only within subclasses of <Foo>.
     */
    public class ScrollListener implements ActionListener {
        // changed this class to public to avoid bogus IllegalAccessException
        // bug in InternetExplorer browser.  It was protected.  Work around
        // for 4109432
        int direction = POSITIVE_SCROLL;
        boolean useBlockIncrement;

        public ScrollListener() {
            direction = POSITIVE_SCROLL;
            useBlockIncrement = true;
        }

        public ScrollListener(int dir, boolean block)   {
            direction = dir;
            useBlockIncrement = block;
        }

        public void setDirection(int direction) {
            this.direction = direction;
        }

        public void setScrollByBlock(boolean block) {
            this.useBlockIncrement = block;
        }

        public void actionPerformed(ActionEvent e) {
            if (useBlockIncrement) {
                scrollByBlock(direction);
            }
            else {
                scrollByUnit(direction);
            }
            if (!trackListener.shouldScroll(direction)) {
                ((Timer)e.getSource()).stop();
            }
        }
    }

    /**
     * Listener for resizing events.
     * <p>
     * This class should be treated as a &quot;protected&quot; inner class.
     * Instantiate it only within subclasses of <Foo>.
     */
    public class ComponentHandler extends ComponentAdapter {
        // NOTE: This class exists only for backward compatability. All
        // its functionality has been moved into Handler. If you need to add
        // new functionality add it to the Handler, but make sure this      
        // class calls into the Handler.
        public void componentResized(ComponentEvent e)  {
            getHandler().componentResized(e);
        }
    };  

    /**
     * Focus-change listener.
     * <p>
     * This class should be treated as a &quot;protected&quot; inner class.
     * Instantiate it only within subclasses of <Foo>.
     */
    public class FocusHandler implements FocusListener {
        // NOTE: This class exists only for backward compatability. All
        // its functionality has been moved into Handler. If you need to add
        // new functionality add it to the Handler, but make sure this      
        // class calls into the Handler.
        public void focusGained(FocusEvent e) {
            getHandler().focusGained(e);
        }

        public void focusLost(FocusEvent e) {
            getHandler().focusLost(e);
        }
    }

    /**
     * As of Java 2 platform v1.3 this undocumented class is no longer used.
     * The recommended approach to creating bindings is to use a
     * combination of an <code>ActionMap</code>, to contain the action,
     * and an <code>InputMap</code> to contain the mapping from KeyStroke
     * to action description. The InputMap is is usually described in the
     * LookAndFeel tables.
     * <p>
     * Please refer to the key bindings specification for further details.
     * <p>
     * This class should be treated as a &quot;protected&quot; inner class.
     * Instantiate it only within subclasses of <Foo>.
     */
    public class ActionScroller extends AbstractAction {
        // NOTE: This class exists only for backward compatability. All
        // its functionality has been moved into Actions. If you need to add
        // new functionality add it to the Actions, but make sure this
        // class calls into the Actions.
        int dir;
        boolean block;
        JSlider slider;

        public ActionScroller( JSlider slider, int dir, boolean block) {
            this.dir = dir;
            this.block = block;
            this.slider = slider;
        }

        public void actionPerformed(ActionEvent e) {
            SHARED_ACTION.scroll(slider, BasicSliderUI.this, dir, block);
	}

	public boolean isEnabled() { 
	    boolean b = true;
	    if (slider != null) {
		b = slider.isEnabled();
	    }
	    return b;
	}

    };


    /**
     * A static version of the above.
     */
    static class SharedActionScroller extends AbstractAction {
        // NOTE: This class exists only for backward compatability. All
        // its functionality has been moved into Actions. If you need to add
        // new functionality add it to the Actions, but make sure this
        // class calls into the Actions.
        int dir;
        boolean block;

        public SharedActionScroller(int dir, boolean block) {
            this.dir = dir;
            this.block = block;
        }

        public void actionPerformed(ActionEvent evt) {
            JSlider slider = (JSlider)evt.getSource();
            BasicSliderUI ui = (BasicSliderUI)BasicLookAndFeel.getUIOfType(
                    slider.getUI(), BasicSliderUI.class);
            if (ui == null) {
                return;
            }
            SHARED_ACTION.scroll(slider, ui, dir, block);
	}
    }

    private static class Actions extends UIAction {
        public static final String POSITIVE_UNIT_INCREMENT =
            "positiveUnitIncrement";
        public static final String POSITIVE_BLOCK_INCREMENT =
            "positiveBlockIncrement";
        public static final String NEGATIVE_UNIT_INCREMENT =
            "negativeUnitIncrement";
        public static final String NEGATIVE_BLOCK_INCREMENT =
            "negativeBlockIncrement";
        public static final String MIN_SCROLL_INCREMENT = "minScroll";
        public static final String MAX_SCROLL_INCREMENT = "maxScroll";


        Actions() {
            super(null);
        }

        public Actions(String name) {
            super(name);
        }

        public void actionPerformed(ActionEvent evt) {
            JSlider slider = (JSlider)evt.getSource();
            BasicSliderUI ui = (BasicSliderUI)BasicLookAndFeel.getUIOfType(