javax.swing.JLayer — clojure-interop/javax.swing 1.0.5

JLayer is a universal decorator for Swing components which enables you to implement various advanced painting effects as well as receive notifications of all AWTEvents generated within its borders.

JLayer delegates the handling of painting and input events to a LayerUI object, which performs the actual decoration.

The custom painting implemented in the LayerUI and events notification work for the JLayer itself and all its subcomponents. This combination enables you to enrich existing components by adding new advanced functionality such as temporary locking of a hierarchy, data tips for compound components, enhanced mouse scrolling etc and so on.

JLayer is a good solution if you only need to do custom painting over compound component or catch input events from its subcomponents.

import javax.swing.; import javax.swing.plaf.LayerUI; import java.awt.;

public class JLayerSample {

private static JLayer<JComponent> createLayer() {
    // This custom layerUI will fill the layer with translucent green
    // and print out all mouseMotion events generated within its borders
    LayerUI<JComponent> layerUI = new LayerUI<JComponent>() {

        public void paint(Graphics g, JComponent c) {
            // paint the layer as is
            super.paint(g, c);
            // fill it with the translucent green
            g.setColor(new Color(0, 128, 0, 128));
            g.fillRect(0, 0, c.getWidth(), c.getHeight());
        }

        public void installUI(JComponent c) {
            super.installUI(c);
            // enable mouse motion events for the layer's subcomponents
            ((JLayer) c).setLayerEventMask(AWTEvent.MOUSE_MOTION_EVENT_MASK);
        }

        public void uninstallUI(JComponent c) {
            super.uninstallUI(c);
            // reset the layer event mask
            ((JLayer) c).setLayerEventMask(0);
        }

        // overridden method which catches MouseMotion events
        public void eventDispatched(AWTEvent e, JLayer<? extends JComponent> l) {
            System.out.println("AWTEvent detected: "  e);
        }
    };
    // create a component to be decorated with the layer
    JPanel panel = new JPanel();
    panel.add(new JButton("JButton"));

    // create the layer for the panel using our custom layerUI
    return new JLayer<JComponent>(panel, layerUI);
}

private static void createAndShowGUI() {
    final JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    // work with the layer as with any other Swing component
    frame.add(createLayer());

    frame.setSize(200, 200);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
}

public static void main(String[] args) throws Exception {
    SwingUtilities.invokeAndWait(new Runnable() {
        public void run() {
            createAndShowGUI();
        }
    });
}

}

Note: JLayer doesn't support the following methods:

Container.add(java.awt.Component) Container.add(String, java.awt.Component) Container.add(java.awt.Component, int) Container.add(java.awt.Component, Object) Container.add(java.awt.Component, Object, int)

using any of of them will cause UnsupportedOperationException to be thrown, to add a component to JLayer use setView(Component) or setGlassPane(JPanel).

->j-layer clj

(->j-layer)

(->j-layer view)

(->j-layer view ui)

Constructor.

Creates a new JLayer object with the specified view component and LayerUI object.

view - the component to be decorated - V ui - the LayerUI delegate to be used by this JLayer - javax.swing.plaf.LayerUI

add-notify clj

(add-notify this)

Notifies this component that it now has a parent component. When this method is invoked, the chain of parent components is set up with KeyboardAction event listeners. This method is called by the toolkit internally and should not be called directly by programs.

create-glass-pane clj

(create-glass-pane this)

Called by the constructor methods to create a default glassPane. By default this method creates a new JPanel with visibility set to true and opacity set to false.

returns: the default glassPane - javax.swing.JPanel

do-layout clj

(do-layout this)

Delegates its functionality to the LayerUI.doLayout(JLayer) method, if LayerUI is set.

get-accessible-context clj

(get-accessible-context this)

Gets the AccessibleContext associated with this JLayer.

returns: the AccessibleContext associated with this JLayer. - javax.accessibility.AccessibleContext

get-glass-pane clj

(get-glass-pane this)

Returns the JLayer's glassPane component or null. This is a bound property.

returns: the JLayer's glassPane component or null if none exists - javax.swing.JPanel

get-layer-event-mask clj

(get-layer-event-mask this)

Returns the bitmap of event mask to receive by this JLayer and its LayerUI.

It means that LayerUI.eventDispatched(AWTEvent, JLayer) method will only receive events that match the event mask.

By default JLayer receives no events.

returns: the bitmask of event types to receive for this JLayer - long

get-preferred-scrollable-viewport-size clj

(get-preferred-scrollable-viewport-size this)

Returns the preferred size of the viewport for a view component.

If the view component of this layer implements Scrollable, this method delegates its implementation to the view component.

returns: the preferred size of the viewport for a view component - java.awt.Dimension

get-scrollable-block-increment clj

(get-scrollable-block-increment this visible-rect orientation direction)

Returns a scroll increment, which is required for components that display logical rows or columns in order to completely expose one block of rows or columns, depending on the value of orientation.

If the view component of this layer implements Scrollable, this method delegates its implementation to the view component.

visible-rect - The view area visible within the viewport - java.awt.Rectangle orientation - Either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL. - int direction - Less than zero to scroll up/left, greater than zero for down/right. - int

returns: the "block" increment for scrolling in the specified direction - int

get-scrollable-tracks-viewport-height? clj

(get-scrollable-tracks-viewport-height? this)

Returns false to indicate that the height of the viewport does not determine the height of the layer, unless the preferred height of the layer is smaller than the height of the viewport.

If the view component of this layer implements Scrollable, this method delegates its implementation to the view component.

returns: whether the layer should track the height of the viewport - boolean

get-scrollable-tracks-viewport-width? clj

(get-scrollable-tracks-viewport-width? this)

Returns false to indicate that the width of the viewport does not determine the width of the layer, unless the preferred width of the layer is smaller than the width of the viewport.

If the view component of this layer implements Scrollable, this method delegates its implementation to the view component.

returns: whether the layer should track the width of the viewport - boolean

get-scrollable-unit-increment clj

(get-scrollable-unit-increment this visible-rect orientation direction)

Returns a scroll increment, which is required for components that display logical rows or columns in order to completely expose one new row or column, depending on the value of orientation. Ideally, components should handle a partially exposed row or column by returning the distance required to completely expose the item.

Scrolling containers, like JScrollPane, will use this method each time the user requests a unit scroll.

If the view component of this layer implements Scrollable, this method delegates its implementation to the view component.

visible-rect - The view area visible within the viewport - java.awt.Rectangle orientation - Either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL. - int direction - Less than zero to scroll up/left, greater than zero for down/right. - int

returns: The "unit" increment for scrolling in the specified direction. This value should always be positive. - int

get-ui clj

(get-ui this)

Returns the LayerUI for this JLayer.

returns: the LayerUI for this JLayer - javax.swing.plaf.LayerUI<? super V>

get-view clj

(get-view this)

Returns the JLayer's view component or null. This is a bound property.

returns: the JLayer's view component or null if none exists - V

optimized-drawing-enabled? clj

(optimized-drawing-enabled? this)

The JLayer overrides the default implementation of this method (in JComponent) to return false. This ensures that the drawing machinery will call the JLayer's paint implementation rather than messaging the JLayer's children directly.

returns: false - boolean

paint clj

(paint this g)

Delegates all painting to the LayerUI object.

g - the Graphics to render to - java.awt.Graphics

paint-immediately clj

(paint-immediately this x y w h)

Delegates its functionality to the LayerUI.paintImmediately(int, int, int, int, JLayer) method, if LayerUI is set.

x - the x value of the region to be painted - int y - the y value of the region to be painted - int w - the width of the region to be painted - int h - the height of the region to be painted - int

property-change clj

(property-change this evt)

This method gets called when a bound property is changed.

evt - A PropertyChangeEvent object describing the event source and the property that has changed. - java.beans.PropertyChangeEvent

remove clj

(remove this comp)

Removes the specified component from this container. This method also notifies the layout manager to remove the component from this container's layout via the removeLayoutComponent method.

This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.

comp - the component to be removed - java.awt.Component

remove-all clj

(remove-all this)

Removes all the components from this container. This method also notifies the layout manager to remove the components from this container's layout via the removeLayoutComponent method.

This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.

remove-notify clj

(remove-notify this)

Notifies this component that it no longer has a parent component. When this method is invoked, any KeyboardActions set up in the the chain of parent components are removed. This method is called by the toolkit internally and should not be called directly by programs.

set-border clj

(set-border this border)

A non-null border, or non-zero insets, isn't supported, to prevent the geometry of this component from becoming complex enough to inhibit subclassing of LayerUI class. To create a JLayer with a border, add it to a JPanel that has a border. Note: If border is non-null, this method will throw an exception as borders are not supported on a JLayer.

border - the Border to set - javax.swing.border.Border

throws: java.lang.IllegalArgumentException - this method is not supported

set-glass-pane clj

(set-glass-pane this glass-pane)

Sets the JLayer's glassPane component, which can be null. This is a bound property.

glass-pane - the glassPane component of this JLayer - javax.swing.JPanel

set-layer-event-mask clj

(set-layer-event-mask this layer-event-mask)

Enables the events from JLayer and all its descendants defined by the specified event mask parameter to be delivered to the LayerUI.eventDispatched(AWTEvent, JLayer) method.

Events are delivered provided that LayerUI is set for this JLayer and the JLayer is displayable.

The following example shows how to correctly use this method in the LayerUI implementations:

public void installUI(JComponent c) {
   super.installUI(c);
   JLayer l = (JLayer) c;
   // this LayerUI will receive only key and focus events
   l.setLayerEventMask(AWTEvent.KEY_EVENT_MASK | AWTEvent.FOCUS_EVENT_MASK);
}

public void uninstallUI(JComponent c) {
   super.uninstallUI(c);
   JLayer l = (JLayer) c;
   // JLayer must be returned to its initial state
   l.setLayerEventMask(0);
}

By default JLayer receives no events and its event mask is 0.

layer-event-mask - the bitmask of event types to receive - long

set-layout clj

(set-layout this mgr)

Sets the layout manager for this container. This method is overridden to prevent the layout manager from being set. Note: If mgr is non-null, this method will throw an exception as layout managers are not supported on a JLayer.

mgr - the specified layout manager - java.awt.LayoutManager

throws: java.lang.IllegalArgumentException - this method is not supported

set-ui clj

(set-ui this ui)

Sets the LayerUI which will perform painting and receive input events for this JLayer.

ui - the LayerUI for this JLayer - javax.swing.plaf.LayerUI

set-view clj

(set-view this view)

Sets the JLayer's view component, which can be null. This is a bound property.

view - the view component for this JLayer - V

update-ui clj

(update-ui this)

Delegates its functionality to the LayerUI.updateUI(JLayer) method, if LayerUI is set.