3.4.2 - Menu Area - JdlMenuArea

John W. Campbell

3.4.2.1 Introduction

Class, fields, constructor and methods:

3.4.2.2 Class Details

Package:

Jdl.JdlView;

Class name:

JdlMenuArea

Class definition:

public class JdlMenuArea

Extends:

JdlDrawPanel

Implements:

ActionListener
MouseListener
JdlViewObject

Actions:

An action event will be generated when a menu item or the quit button is selected. The associated object is the string 'item n' respectively where 'n' is the selected menu item number from 1 up or 0 if the 'quit' button was selected.

3.4.2.3 Accessible Fields

public final static int FULL_WIDTH

Button width option: use maximum allowed button widths.

public final static int ITEMS_WIDTH

Button width option: use button widths based on longest item string in current set of displayed items.

static final long serialVersionUID

public final static int PREFERRED

Size Constraint: preferred size.

public final static int FREE

Size/Location Constraint: free.

3.4.2.4 Constructor

3.4.2.4.1 Introduction

Constructor:

3.4.2.4.2 Standard constructor

Constructor Definition:

public JdlMenuArea(String title, String[] menu_strings, int num_strings, String quit_string, int max_items, int input_string_width, boolean allow_title, boolean allow_quit, int minimum_width, int minimum_height, JdlMenuAreaStyle style, JdlViewOptions view_opts)

Parameters List:

title

The initial menu title, may be null if not required.

menu_strings

The menu item strings for the initial menu to be displayed.

num_strings

The number of menu item strings in the array menu_strings; may be input as 0 if the number of strings to be used is the same as the String array length.

quit_string

The initial menu string for the 'quit' button, may be null if not required.

max_items

The maximum number of items for which this menu area may be used (used in menu area size calculations).

input_string_width

A pre-calculated string width (in pixels) to override the string width calculated from the current set of title/menu/quit strings. If 0, then ignore this value.

allow_title

Allow for a menu title to be displayed (used in menu area size calculations).

allow_quit

Allow for a quit button to be displayed (used in menu area size calculations).

minimum_width

The minimum width requested (only used if greater than the minimum needed for the layout.

minimum_height

The minimum height requested (only used if greater than the minimum needed for the layout.

style

Allows for non-default settings for various button style parameters (If null, the default values for these will be used).

view_opts

Object to set non-default options for borders, active strip, colours and fonts.

3.4.2.5 Operational Methods

3.4.2.5.1 Introduction

Methods:

3.4.2.5.2 Set menu strings - setMenuStrings

Method Definition:

public void setMenuStrings(String[] menu_strings, int num_strings)

Parameters List:

menu_strings

An array of new nenu item strings.

num_strings

The number of menu item strings in the array menu_strings; may be input as 0 if the number of strings to be used is the same as the String array length. Note: The number of strings must not exceed the maximum number of menu items defined when the object was created.

3.4.2.5.3 Set quit string - setQuitString

Method Definition:

public void setQuitString(String quit_string)

Parameters List:

quit_string

The quit string.

3.4.2.5.4 Set title string - setTitleString

Method Definition:

public void setTitleString(String title_string)

Parameters List:

title_string

The title string.

3.4.2.5.5 Create popup - popupMenu

Method Definition:

public synchronized int popupMenu(Component parent, int x, int y, boolean mouse_esc, long timeout)

Parameters List:

parent

The parent view object (or Component).

x

The 'x' coordinate of the popup relative to the parent.

y

The 'y' coordinate of the popup relative to the parent.

mouse_esc

Allow for menu escape if mouse clicked outside a button if true, otherwise an item/quit-item must be selected.

timeout

The popup menu will time out after this number of milliseconds if a value greater than zero is given. If 0, no timeout will occur.

Method Return:

Selected item flag:
> 0, The number of the menu item selected
= 0, The quit item was selected
= -1, Mouse was clicked outside an item (if mouse_esc = true)
= -2, Menu timeout (if timeout > 0)

3.4.2.6 Standard Positioning and Sizing

3.4.2.6.1 Introduction

Methods:

3.4.2.6.2 Set position constraints - setLocationConstraints

Method Definition:

public void setLocationConstraints (int constraint_x, int constraint_y)

Parameters List:

constraint_x

Constrain the Jdl Object 'x' position = the required Jdl Object 'x' position (overrides setLocation method) or FREE if the 'x' position may be set by the setLocation method and hence possibly by the layout manager.

constraint_y

Constrain the Jdl Object 'y' position = the required the Jdl Object 'y'position (overrides setLocation method) or FREE if the 'y' position may be set by the setLocation method and hence possibly by the layout manager.

3.4.2.6.3 Set size constraints - setSizeConstraints

Method Definition:

public void setSizeConstraints (int constraint_w, int constraint_h)

Parameters List:

constraint_w

Constrain the Jdl Object width = the required Jdl Object width, or PREFERRED (default) if the width is to be calculated from the current resources, or FREE if the width may be resized to anything greater than the minimum width required.

constraint_h

Constrain the Jdl Object height = the required Jdl Object height, or PREFERRED (default) if the height is to be calculated from the current resources, or FREE if the height may be resized to anything greater than the minimum height required.

3.4.2.6.4 Set minimum height - setMinimumHeight

Method Definition:

public void setMinimumHeight(int minh)

Parameters List:

minh

The minimum height required for the object (ignored if less than that required by the minimum layout) (default = 0).

3.4.2.6.5 Set minimum width - setMinimumWidth

Method Definition:

public void setMinimumWidth(int minw)

Parameters List:

minh

The minimum width required for the object (ignored if less than that required by the minimum layout) (default = 0).

3.4.2.7 Add/Remove Action Listener

3.4.2.7.1 Introduction

Methods:

3.4.2.7.2 Add action listener - addActionListener

Method Definition:

public void addActionListener(ActionListener listener)

Parameters List:

listener

The action listener to be added.

3.4.2.7.3 Remove an action listener. - removeActionListener

Method Definition:

public void removeActionListener(ActionListener listener)

Parameters List:

listener

The action listener to be added.

3.4.2.8 Get Returned Data

3.4.2.8.1 Introduction

Methods:

3.4.2.8.2 Get menu item number - getReturnedData

Method Definition:

public int getReturnedData()

Parameters List:

none

Method Return:

Returns the last selected menu item number or 0 if quit item was selected.

3.4.2.9 Overriden Superclass Methods

3.4.2.9.1 Introduction

Methods:

3.4.2.9.2 Set background - setBackground

Method Definition:

public void setBackground (Color c)

Parameters List:

c

The color to become this object's background color.

3.4.2.9.3 Set background colours - setBackground

Method Definition:

public void setBackground (Color c, Color brighter, Color darker)

Parameters List:

c

The background colour.

brighter

A brighter shade of the background colour.

darker

A darker shade of the background colour.

3.4.2.9.4 Set foreground - setForeground

Method Definition:

public void setForeground (Color c)

Parameters List:

c

The color to become this object's foreground color.

3.4.2.9.5 Get minimum size - getMinimumSize

Method Definition:

public Dimension getMinimumSize()

Parameters List:

none

3.4.2.9.6 Get preferred size - getPreferredSize

Method Definition:

public Dimension getPreferredSize()

Parameters List:

none