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JButton typedict
 
A JButton is the interface to the Java Swing JButton, JCheckBox, JRadioButton and JToggleButton Components. Yoix programs normally interact with a JButton using event handlers and by reading or writing the following fields:
alignment An int that controls the horizontal positioning of the text in the button. The value should be LEFT, CENTER, RIGHT, LEADING, or TRAILING, which are all defined in yoix.swing. Reading returns the current alignment. Writing immediately repaints the text using the new alignment. The default value is CENTER.
armed An int that is 1 when the button is armed (i.e., partially committed to being pressed) and 0 otherwise. Reading returns the current armed status. Writing immediately changes the armed status. Mostly this field is of use inside the stateChanged event handler.
autotrim An int that is 1 when white space is automatically trimmed from both ends of every string read from or written to the text field, and 0 otherwise.
background The Color that is used to paint the background of the button. Reading returns a snapshot of the current color. Writing immediately changes the background to the new color. Storing NULL in background is special and means use the background of the nearest component that contains the button and was assigned a background color other than NULL; if no component qualifies the button uses VM.screen.background.
border An Object that should be a Border, Insets, Number, or String that describes the border that is drawn around this button. A NULL value, which is the default, means no border. A border that is an Insets or Number is an easy way to describe margins (i.e., an EmptyBorder), in units of 72 dots per inch, that are left around the sides of this button. A border that is a String is a quick way to surround this button with a border that uses the String as its title. Reading returns a snapshot of the current border. Writing immediately sets the button's border to the new value.
click([Number time]) A Builtin that causes the button to behave as if it has just been interactively clicked. The optional time argument, when supplied, is the number of seconds the button will remain depressed.
command A String that is assigned to the command field in the ActionEvent that is generated when the button is clicked. The value stored in the button's text field is used when command is set to NULL.
cursor An Object that should be an int, Image, or String that selects the cursor shown when the pointer is over the button. A cursor that is an int should be one of the cursors defined in the yoix.awt.Cursor dictionary. A cursor that is an Image can describe the cursor using its size and hotspot fields and often draws it using its paint function. A cursor that is a String should be the name of a cursor that is already defined in yoix.awt.Cursor or the name a local a file or URL that contains a GIF or JPEG image that will be used as the cursor.

Reading returns the current cursor. Writing immediately changes the button's cursor to the new value. Storing STANDARD_CURSOR (the default) or NULL in cursor is special and means use the cursor assigned to the nearest component that contains the button and was assigned a cursor other than STANDARD_CURSOR; if no component qualifies the button uses DEFAULT_CURSOR.

doublebuffered An int that is 1 when the button uses double-buffering to draw itself, 0 when it does not, and starts with a default value that is selected by Java for the button. Reading returns the current double-buffering behavior. Writing immediately sets the button's double-buffering behavior to the new value. Note that double-buffering may be required when transparent components are used.
dragenabled An int that should be set to 1 when this button wants to use the automatic drag handling that Swing provides for some components, and 0 (the default) when it does not. Components that do not provide automatic drag handling always return 0 when their dragenabled field is read, so storing 1 in dragenabled should only be viewed as a request for a service that may not be available. Swing components can always take complete control of their drag and drop handling using their transferhandler field or special drag and drop event handlers.
enabled An Object that is 1 when the button can respond to user input, 0 when it can not respond, and NULL (the default) when the button inherits the value from the nearest lightweight container, like a JPanel, that contains the button and has its enabled field set to something other than NULL. The top-level application window that contains the button always gets the final say, so disabling that window always disables the button. Reading returns the current state. Writing immediately sets the button's state to the new value.
focusowner A read-only int that is non-zero when the button has the focus.
font The Font, or font name if it is a String, used to paint the characters stored in the text field. Reading returns a snapshot of the current font. Writing immediately repaints the text in the new font.
foreground The Color that is used to paint the characters stored in the text field. Reading returns a snapshot of the current color. Writing immediately repaints the text in the new color. Storing NULL in foreground is special and means use the foreground of the nearest component that contains the button and was assigned a foreground color other than NULL; if no component qualifies the button uses VM.screen.foreground.
group The ButtonGroup, if any, containing this button. Reading returns the currently associated group, writing assigns the currently associated group. Button groups are used to enforce a multiple-exclusion scope on the set of buttons in the group. Usually a button of type RADIO_BUTTON is used in conjunction with a ButtonGroup.
icon A read-write Image to be used as the defaulticon for this button. This field is a convenience field and is equivalent to the defaulticon element in the icons dictionary discussed below.
icons A read-write Dictionary of Image fields that specify the icons to be used in the seven potential states of the button. The seven fields are defaulticon, disabledicon, disabledselectedicon, pressedicon, rollovericon, rolloverselectedicon and selectedicon. If pressedicon or disabledicon are not explicitly specified, the value of defaulticon is applied to them.
insets An Object, usually an Insets or Number, that describes the margins, in units of 72 dots per inch, that separate the button from its default border. This field is not automatically used when the button builds its own border. An insets that is a number is an easy way to describe a uniform margin. Writing immediately changes the margins that are drawn around the button by the default border.
layer An int, often a small number between 0 and 99, that identifies the depth of this button when it is added to a JLayeredPane or JDesktopPane. Components assigned to lower numbered layers are drawn before the components in higher numbered layers. Writing immediately changes the button's layer, which usually means the JLayeredPane or JDesktopPane that contains the button will be repainted.
location A Point that determines the location of the button in a coordinate system that has its origin at the upper left corner of the container closest to the button (in the component hierarchy) that actually contains it, positive x to the right, positive y down, and a resolution of 72 dots per inch. Reading returns a snapshot of the current location. Writing is allowed, but layout managers usually get the final say, so setting location should be viewed as a request that may not be honored.
mnemonic An int that sets the keyboard mnemonic for the button. The integer value represents, in a case-insensitive manner, a single key on the keyboard. It is recommended that elements in the yoix.swing.KeyCode dictionary be used for assigning mnemonic values. Refer to the Java AbstractButton documentation for more information about mnemonic usage.
nextfocus An Object that is the component that receives the focus after this button when the focus traverses from one component to the next (usually by means of the keyboard TAB character). A NULL value indicates that the default Java focus traversal is in effect. Reading returns the value last stored. Writing immediately sets the new focus traversal behavior.
opaque An Object that is 1 when the button is opaque, 0 when it is transparent, and NULL (the default) when the button inherits the value from the nearest component that contains the button and has its opaque field set to something other than NULL.
popup A JPopupMenu that is associated with the button. Reading returns the current popup menu. Writing immediately shows the popup menu at the point in the button's coordinate system specified by the popup menu's location field, assuming of course that the button is showing on the screen. Storing TRUE in the popup menu's visible field, which was added in release 1.2.0, is an easy way to show the popup menu that currently belongs to the button.
preferredsize A Dimension that is used by layout managers when they need to know the button's preferred size in units of 72 dots per inch. A NULL value means the button has no preference. A non-positive height or width is allowed and simply means the button has no preference for that dimension. Reading returns the current preferred size. Writing changes the preferred size and immediately notifies root.layoutmanager, which means the components contained in root may be repositioned and resized.
pressed An int that is 1 when the button is pressed and 0 otherwise. Reading returns the current pressed status. Writing immediately changes the pressed status. Mostly this field is of use inside the stateChanged event handler.
requestfocus An int that can be used to request or transfer the keyboard focus. Storing a non-zero value in requestfocus tries to get the focus. Storing 0 tries to transfer the focus. Reading requestfocus does not currently return any useful information.
requestfocusenabled An int that is 1 (the default) when actions, like mouse clicks or changes to the requestfocus field, can steal the keyboard focus and 0 when they can not. Note that this field does not affect acceptance of the keyboard focus during normal focus traversal. Reading returns the current state. Writing immediately sets the button's state to the new value.
rolloverenabled An int that is 1 when a rollover (i.e., the mouse entering or exiting the button) will be registered, or 0 (the default) when it will not. Note that this field does not affect changing the rollover state by assigning a value to the rollover field. Reading returns the current state. Writing immediately sets the button's state to the new value.
rollover An int that is 1 when the mouse is over the button and 0 otherwise. Reading returns the current rollover status. Writing immediately changes the rollover status. Mostly this field is of use inside the stateChanged event handler.
root An Object that is automatically updated by the interpreter's layout machinery so it is always the top-level object that contains the button. For example, put a button in a panel and root will be set to that panel; add the panel to a frame and the button's root field will be set to that frame. A button's event handlers can use root when they need to interact with the other components in the container.
selected A synonym for state, which is preferred. This field is retained for backward compatibility.
showing A read-only int that is non-zero when the button is showing on the screen.
size A Dimension that determines the size of the button in units of 72 dots per inch. Reading returns a snapshot of the current size. Writing is allowed, but layout managers usually get the final say, so setting size should be viewed as a request that may not be honored.
state An int that is 1 when the button is selected and 0 otherwise. For a standard button, this field has no real meaning and setting it in that case has no meaningful effect.
tag A String used to identify the button that is either supplied when the button is declared, or automatically generated otherwise. Add a button to a container, like a JFrame or JPanel, and the interpreter's layout machinery updates the root field so it points at the top-level container and then adds the button, as tag, to the root.components dictionary.
text A String of characters that is aligned, as indicated by the alignment field, in the button. Reading returns the current text. Writing immediately paints the new text.
textposition An int that controls the horizontal positioning of the text in the button relative to its icon. The value should be LEFT, CENTER, RIGHT, LEADING, or TRAILING, which are all defined in yoix.swing. Reading returns the current alignment. Writing immediately repaints the text using the new alignment. The default value is TRAILING.
tooltiptext A String of characters that is displayed in a tightly sized pop-up window that appears near the cursor whenever the cursor lingers over the button. Setting this value to NULL (the default) disables the tooltip mechanism. Reading returns the current tooltip text. Writing immediately sets the new tooltip text.
transferhandler An Object that should be a TransferHandler or String that determines how the button handles data transfer operations like drag and drop. A value that is a String but not "" means the field named by the String should be used as the source and sink of the data that is transferred by the button. The result is the same as assigning the String to the property field in a TransferHandler and then assigning that TransferHandler to transferhandler. The empty String "" is special and refers to the TransferHandler that Swing uses for automatic drag handling, if there is one.

Swing components that provide automatic drag handling start out with a transferhandler field that is not NULL, but the automatic drag handling is not enabled until 1 is stored in dragenabled. Swing components that provide their own drag and drop event handlers currently must store NULL in transferhandler before those event handlers will start working.

type An int variable that can only be set at creation time to specify the type of button. The types, which are all defined in yoix.swing, are STANDARD_BUTTON, CHECKBOX_BUTTON RADIO_BUTTON, and TOGGLE_BUTTON. The default is STANDARD_BUTTON.
visible An int that is 1 when the button is visible, and 0 otherwise. Reading returns the current visibility. Writing immediately sets the button's visibility to the new state.
Several permanent fields have not been documented and should not be used in Yoix applications. Event handlers are functions that must be added to a button when it is declared. The handlers that work with buttons are listed below; the names should be familiar if you have done some Java programming.
 
 Event Handlers:   actionPerformed, componentHidden, componentMoved, componentResized, componentShown, dragDropEnd, dragEnter, dragExit, dragGestureRecognized, dragMouseMoved, dragOver, drop, dropActionChanged, focusGained, focusLost, invocationRun, itemStateChanged, keyPressed, keyReleased, keyTyped, mouseClicked, mouseDragged, mouseEntered, mouseExited, mouseMoved, mousePressed, mouseReleased, mouseWheelMoved stateChanged
 
 Example:   The program,
import yoix.*.*;

JFrame f = {
    FlowLayout layoutmanager = {
        int hgap = 10;
        int vgap = 72;
    };

    Array layout = {
        new JButton {
            String tag = "$_update";
            String text = "Update";
            int    mnemonic = KeyCode.VK_U;
            int    requestfocus = TRUE;

            actionPerformed(e) {
                root.components.$_random.text = toString(random());
            }
        },

        new JButton {
            String tag = "$_random";
            String text = toString(random());
            String tooltiptext = "Hit 'Update' to change this text";
            String font = "Helvetica-bold-14";
        },

        new JButton {
            String tag = "$_quit";
            String text = "Quit";
            int    mnemonic = KeyCode.VK_Q;

            actionPerformed(e) {
                exit(0);
            }
        },
    };
};

f.components.$_update.nextfocus = f.components.$_quit;
f.visible = TRUE;
adds three buttons to a frame, updates the middle button's label, using the output of the random built-in, when the left button is pressed, and quits when the right button is pressed. In addition, a tooltip is assigned to the middle button and focus traversal skips over the middle button.
 
 See Also:   appendText, BevelBorder, Border, ButtonGroup, EmptyBorder, EtchedBorder, invokeLater, JCanvas, JCheckBox, JCheckBoxGroup, JCheckBoxMenuItem, JChoice, JColorChooser, JComboBox, JDesktopPane, JDialog, JFileChooser, JFileDialog, JFrame, JInternalFrame, JLabel, JLayeredPane, JList, JMenu, JMenuBar, JMenuItem, JPanel, JPasswordField, JPopupMenu, JProgressBar, JRadioButton, JRadioButtonMenuItem, JScrollBar, JScrollPane, JSeparator, JSlider, JSplitPane, JTabbedPane, JTable, JTextArea, JTextCanvas, JTextField, JTextPane, JTextTerm, JToggleButton, JToolBar, JTree, JWindow, LineBorder, MatteBorder, postEvent, SoftBevelBorder, TransferHandler

 

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