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Chapter 24 Advanced Swing Components

1.Yes. Each Swing GUI component (except some containers and dialog boxes such as

JPanel, JsplitPane, JFileChooser, and JColorChooser) have a property named model.

No. The type of the model property is dependent on the component. For JList, the

model type is ListModel and JSpinner, the model type is SpinnerModel. Generally,

the model interface is named X Model for the X component.

2.Yes in most cases and no in some rare cases. Most model interface has a default

implementation class that is commonly named Default X, where X is its model

interface name. For example, the default implementation class for ListModel is

DefaultListModel.

Yes in most cases and no in some rare cases. Most Swing components use their

default model classes if no model is specified. However, it is not true for JList.

3. The default model is SpinnerNumberModel if you don’t specify a model when

creating a JSpinner.

4.The internal data structure for storing data in SpinnerListModel is java.util.Vector. A

simple way to convert an array to a vector is to use the static method Arrays.asList to

obtain a list, then use the list to construct a vector.

5.No. You have to add items to a list using a ListModel. You can display icons and

custom GUI objects in list. List items cannot be edited. You can initialize data from

JList constructor. To specify the maximum number of rows without scrolling, set the

JList’s visibleRowCount property. To specify the height of a list cell, set the JList’s

fixedCellHeight property. To specify the horizontal margin of list cells, set the JList’s

fixedCellWidth property.

6. A simple way to create a list model is using the DefaultListModel class. To add items

to a list model, use the various add method in the DefaultListModel. To remove items

from a list model, use the various remove method in the DefaultListModel.

7.The three list-selection modes are single selection, single-interval selection, and

multiple-interval selection. You can set the selection modes directly in an instance of

JList using the setSelectionMode method. To obtain the selected item(s), use the

getSelectedValue or getSelectedValues methods.

8.To create a custom list cell renderer, implement the ListCellRenderer interface and its

getListCellRendererComponent method.

9.The handler for handling the ListSelectionEvent is valueChanged(ListSelectionEvent

e).

10.Only a single item can be selected from a combo box. A combo box item can be

edited. To specify the maximum number of visible rows in a combo box without

scrolling, set the maximumRowCount method. There are no methods in JComboBox

that use can use to specify the height of a combo box cell. To obtain the selected item

in a combo box, use the getSelectedItem method.

11.To add or remove items from a combo box, you may use JComboBox’s add and

remove methods, or use the add and remove methods from the ComboBoxModel.

12.The cell renderer for a combo box is the same as the renderer for a list, since they

both implement ListCellRenderer.

13.You can initialize a table using the constructor of JTable. You cannot specify the

maximum number of visible rows in a table without scrolling. You can specify the

height of a table cell using the setRowHeight method. You can specify the horizontal margin of table cells using the setIntercellSpacing method.

14.To modify table contents visually from the UI, the

table cells must be editable with an associated editor

for the cell. You must also save the change through the

data model. To add or remove a row, you must use a

TableModel. The DefaultTableModel class provides methods

for adding and removing rows. To add a column, you may

use the addColumn method in DefaultTableModel or in

DefaultTableColumnModel. To remove a column, you must use the removeTableColumn method from the

DefaultTableColumnModel class.

15.JTable has the autoResizingMode property that can be

used to auto resize a table column. Possible values are:

JTable.AUTO_RESIZE_OFF

JTable.AUTO_RESIZE_LAST_COLUMN

JTable.AUTO_RESIZE_SUBSEQUENT_COLUMNS

JTable.AUTO_RESIZE_NEXT_COLUMN

JTable.AUTO_RESIZE_ALL_COLUMNS

16.The properties to show grids, horizontal grids, and

vertical grids are showGrid, showHorizontalGrid, and

showVerticalGrid. The properties to specify the table row height, and vertical margin are rowHeight and rowMargin.

There are no methods to set horizontal margins between

the cells, because this type of margin is flexible.

17.By default, a cell object's string representation is

displayed and the string can be edited as it was in a

text field. JTable maintains a set of predefined

renderers and editors, listed in Table 8.1, which can be

specified to replace default string renderers and

editors. You can create a custom renderer by extending

the DefaultTableCellRenderer class.

18.To create a tree, simply use the constructor of JTtree.

To specify the row height of a tree node, use the

rowHeight property. To obtain the default tree model and

tree selection model from an instance of JTree, use

getModel and getSelectionModel methods.

19.To initialize data in a tree using TreeModel, you need

to create nodes using the DefaultMutableTreeNode class, and set the root with the TreeModel (or

DefaultTreeModel). To add a child to an instance of

DefaultMutableTreeNode, use the add method.

20.To add a node from a tree, use the add method from an

instance of DefaultMutableTreeNode in a parent. To remove

a node from a tree, use the removeNodeFromParent method

from TreeModel.

21.To obtain a selected tree node, use the

getleadSelectedPath method to get the path, then get the node from the path using the getLastPathComponent method.