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Chapter 19 java.awt Reference |
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Toolkit
Name
Toolkit
![[Graphic: Figure from the text]](./figs/toolkit.gif)
Description
The abstract Toolkit class provides access to platform-specific details like window size and available fonts. It also deals with creating all the components' peer objects when you call addNotify().
Class Definition
public abstract class java.awt.Toolkit
extends java.lang.Object {
// Class Methods
public static synchronized Toolkit getDefaultToolkit();
protected static Container getNativeContainer (Component c); 
public static String getProperty (String key, String defaultValue);
// Instance Methods
public abstract void beep();
public abstract int checkImage (Image image, int width, int height,
ImageObserver observer);
public abstract Image createImage (ImageProducer producer);
public Image createImage (byte[] imagedata);
public abstract Image createImage (byte[ ] imagedata, int imageoffset,
int imagelength);
public abstract ColorModel getColorModel();
public abstract String[] getFontList();
public abstract FontMetrics getFontMetrics (Font font);
public abstract Image getImage (String filename);
public abstract Image getImage (URL url);
public int getMenuShortcutKeyMask();
public abstract PrintJob getPrintJob (Frame frame, String jobtitle,
Properties props);
public abstract int getScreenResolution();
public abstract Dimension getScreenSize();
public abstract Clipboard getSystemClipboard();
public final EventQueue getSystemEventQueue();
public abstract boolean prepareImage (Image image, int width, int height,
ImageObserver observer);
public abstract void sync();
// Protected Instance Methods
protected abstract ButtonPeer createButton (Button b);
protected abstract CanvasPeer createCanvas (Canvas c);
protected abstract CheckboxPeer createCheckbox (Checkbox cb);
protected abstract CheckboxMenuItemPeer createCheckboxMenuItem
(CheckboxMenuItem cmi);
protected abstract ChoicePeer createChoice (Choice c);
protected LightweightPeer createComponent(Component target);
protected abstract DialogPeer createDialog (Dialog d);
protected abstract FileDialogPeer createFileDialog (FileDialog fd);
protected abstract FramePeer createFrame (Frame f);
protected abstract LabelPeer createLabel (Label l);
protected abstract ListPeer createList (List l);
protected abstract MenuPeer createMenu (Menu m);
protected abstract MenuBarPeer createMenuBar (MenuBar mb);
protected abstract MenuItemPeer createMenuItem (MenuItem mi);
protected abstract PanelPeer createPanel (Panel p);
protected abstract PopupMenuPeer createPopupMenu (PopupMenu target);
protected abstract ScrollPanePeer createScrollPane (ScrollPane target);
protected abstract ScrollbarPeer createScrollbar (Scrollbar sb);
protected abstract TextAreaPeer createTextArea (TextArea ta);
protected abstract TextFieldPeer createTextField (TextField tf);
protected abstract WindowPeer createWindow (Window w);
protected abstract FontPeer getFontPeer (String name, int style);
protected abstract EventQueue getSystemEventQueueImpl();
protected void loadSystemColors (int[] systemColors);
}
Class Methods
getDefaultToolkit
public static synchronized Toolkit getDefaultToolkit()
- Throws
-
- AWTError
-
If the toolkit for the current platform cannot be found.
- AWTError
- Returns
-
The system's default Toolkit.
getNativeContainer
protected static Container getNativeContainer (Component c)
- Returns
-
The native container for the given component. The component's immediate parent may be a lightweight component.
getProperty
public static String getProperty (String key, String defaultValue)
- Parameters
-
- key
-
The name of a property.
- defaultValue
-
A default value to return if the property is not found.
- key
- Returns
-
The value of the property described by key, or defaultValue if it is not found.
Instance Methods
beep
public abstract void beep()
- Description
-
Produces an audible beep.
checkImage
public abstract int checkImage (Image image, int width, int height, ImageObserver observer)
- Parameters
-
- image
-
Image to check.
- width
-
Width of the scaled image; -1 if image will be rendered unscaled.
- height
-
Height of the scaled image; -1 if image will be rendered unscaled.
- observer
-
The Component that image will be rendered on.
- image
- Returns
-
The ImageObserver flags ORed together for the data that is now available.
- Description
-
Checks on the status of the construction of a screen representation of image on observer.
createImage
public abstract Image createImage (ImageProducer producer)
- Parameters
-
- producer
-
An ImageProducer that generates data for the desired image.
- producer
- Returns
-
Newly created Image.
- Description
-
Creates a new Image from an ImageProducer.
public abstract Image createImage (byte[] imagedata)
- Parameters
-
- imagedata
-
Raw data representing an image.
- imagedata
- Returns
-
Newly created Image.
- Description
-
Creates a new Image from the imagedata provided.
public abstract Image createImage (byte[] imagedata, int imageoffset, int imagelength)
- Parameters
-
- imagedata
-
Raw data representing one or more images.
- imageoffset
-
An offset into the data given.
- imagelength
-
The length of data to use.
- imagedata
- Returns
-
Newly created Image.
- Description
-
Creates a new Image from the imagedata provided, starting at imageoffset bytes and reading imagelength bytes.
getColorModel
public abstract ColorModel getColorModel()
- Returns
-
The current ColorModel used by the system.
getFontList
public abstract String[] getFontList()
- Returns
-
A String array of the set of Java fonts available with this Toolkit.
getFontMetrics
public abstract FontMetrics getFontMetrics (Font font)
- Parameters
-
- font
-
A Font whose metrics are desired
- font
- Returns
-
The current FontMetrics for the font on the user's system.
getImage
public abstract Image getImage (String filename)
- Parameters
-
- filename
-
Location of Image on local filesystem
- filename
- Returns
-
The Image that needs to be fetched.
- Description
-
Fetches an image from the local file system.
public abstract Image getImage (URL url)
- Parameters
-
- url
-
Location of Image.
- url
- Returns
-
The Image that needs to be fetched.
- Description
-
Fetches an image from a URL.
getMenuShortcutKeyMask
public int getMenuShortcutKeyMask()
- Returns
-
The modifier key mask used for menu shortcuts. This will be one of the mask constants defined in java.awt.Event.
getPrintJob
public abstract PrintJob getPrintJob (Frame frame, String jobtitle, Properties props)
- Parameters
-
- frame
-
The frame to be used as the parent of a platform-specific printing dialog.
- jobtitle
-
The name of the job.
- props
-
Properties for this print job.
- frame
- Returns
-
A PrintJob object. If the user canceled the printing operation, null is returned.
getScreenResolution
public abstract int getScreenResolution()
- Returns
-
The current resolution of the user's screen, in dots-per-inch.
getScreenSize
public abstract Dimension getScreenSize()
- Returns
-
The size of the screen available to the Toolkit, in pixels, as a Dimension object.
getSystemClipboard
public abstract Clipboard getSystemClipboard()
- Returns
-
A Clipboard object that can be used for cut, copy, and paste operations.
getSystemEventQueue
public final EventQueue getSystemEventQueue()
- Returns
-
A reference to the system's event queue, allowing the program to post new events or inspect the queue.
prepareImage
public abstract boolean prepareImage (Image image, int width, int height, ImageObserver observer)
- Parameters
-
- image
-
Image to check.
- width
-
Width of the scaled image; -1 if image will be rendered unscaled.
- height
-
Height of the scaled image; -1 if image will be rendered unscaled.
- observer
-
The Component that image will be rendered on.
- image
- Returns
-
true if image fully loaded, false otherwise.
- Description
-
Forces the system to start loading the image.
sync
public abstract void sync()
- Description
-
Flushes the display of the underlying graphics context.
Protected Instance Methods
createButton
protected abstract ButtonPeer createButton (Button b)
- Parameters
-
- b
-
Component whose peer needs to be created.
- b
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Button.
createCanvas
protected abstract CanvasPeer createCanvas (Canvas c)
- Parameters
-
- c
-
Component whose peer needs to be created.
- c
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Canvas.
createCheckbox
protected abstract CheckboxPeer createCheckbox (Checkbox cb)
- Parameters
-
- cb
-
Component whose peer needs to be created.
- cb
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Checkbox.
createCheckboxMenuItem
protected abstract CheckboxMenuItemPeer createCheckboxMenuItem (CheckboxMenuItem cmi)
- Parameters
-
- cmi
-
Component whose peer needs to be created.
- cmi
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the CheckboxMenuItem.
createChoice
protected abstract ChoicePeer createChoice (Choice c)
- Parameters
-
- c
-
Component whose peer needs to be created.
- c
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Choice.
createComponent
protected LightweightPeer createComponent (Component target)
- Parameters
-
- target
-
Component whose peer needs to be created.
- target
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Component.
createDialog
protected abstract DialogPeer createDialog (Dialog d)
- Parameters
-
- d
-
Component whose peer needs to be created.
- d
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Dialog.
createFileDialog
protected abstract FileDialogPeer createFileDialog (FileDialog fd)
- Parameters
-
- fd
-
Component whose peer needs to be created.
- fd
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the FileDialog.
createFrame
protected abstract FramePeer createFrame (Frame f)
- Parameters
-
- f
-
Component whose peer needs to be created.
- f
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Frame.
createLabel
protected abstract LabelPeer createLabel (Label l)
- Parameters
-
- l
-
Component whose peer needs to be created.
- l
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Label.
createList
protected abstract ListPeer createList (List l)
- Parameters
-
- l
-
Component whose peer needs to be created.
- l
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the List.
createMenu
protected abstract MenuPeer createMenu (Menu m)
- Parameters
-
- m
-
Menu whose peer needs to be created.
- m
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the given Menu.
createMenuBar
protected abstract MenuBarPeer createMenuBar (MenuBar mb)
- Parameters
-
- mb
-
MenuBar whose peer needs to be created.
- mb
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the MenuBar.
createMenuItem
protected abstract MenuItemPeer createMenuItem (MenuItem mi)
- Parameters
-
- mi
-
MenuItem whose peer needs to be created.
- mi
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the MenuItem.
createPanel
protected abstract PanelPeer createPanel (Panel p)
- Parameters
-
- p
-
Component whose peer needs to be created.
- p
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Panel.
createPopupMenu
protected abstract PopupMenuPeer createPopupMenu (PopupMenu target)
- Parameters
-
- target
-
Component whose peer needs to be created.
- target
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the PopupMenu.
createScrollPane
protected abstract ScrollPanePeer createScrollPane (ScrollPane target)
- Parameters
-
- target
-
Component whose peer needs to be created.
- target
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the ScrollPane.
createScrollbar
protected abstract ScrollbarPeer createScrollbar (Scrollbar sb)
- Parameters
-
- sb
-
Component whose peer needs to be created.
- sb
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Scrollbar.
createTextArea
protected abstract TextAreaPeer createTextArea (TextArea ta)
- Parameters
-
- ta
-
Component whose peer needs to be created.
- ta
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the TextArea.
createTextField
protected abstract TextFieldPeer createTextField (TextField tf)
- Parameters
-
- tf
-
Component whose peer needs to be created.
- tf
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the TextField.
createWindow
protected abstract WindowPeer createWindow (Window w)
- Parameters
-
- w
-
Component whose peer needs to be created.
- w
- Returns
-
Newly created peer.
- Description
-
Creates a peer for the Window.
getFontPeer
protected abstract FontPeer getFontPeer (String name, int style)
- Parameters
-
- name
-
Name of the font to be created.
- style
-
Style of the font to be created.
- name
- Returns
-
Newly created peer.
- Description
-
Creates a FontPeer.
getSystemEventQueueImpl
protected abstract getSystemEventQueueImpl()
- Returns
-
A toolkit-specific EventQueue object.
loadSystemColors
protected abstract void loadSystemColors (int[] systemColors)
- Description
-
Fills the given integer array with the current system colors.
See Also
Button, ButtonPeer, Canvas, CanvasPeer, Checkbox, CheckboxMenuItem, CheckboxMenuItemPeer, CheckboxPeer, Choice, ChoicePeer, Clipboard, ColorModel, Component, Container, Dialog, DialogPeer, Dimension, FileDialog, FileDialogPeer, Font, FontMetrics, FontPeer, Frame, FramePeer, Image, ImageObserver, ImageProducer, Label, LabelPeer, LightweightPeer, List, ListPeer, Menu, MenuBar, MenuBarPeer, MenuItem, MenuItemPeer, MenuPeer, Panel, PanelPeer, PrintJob, Scrollbar, ScrollbarPeer, ScrollPane, ScrollPanePeer, String, TextArea, TextAreaPeer, TextField, TextFieldPeer, Window, WindowPeer
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