Layout Managers

What is a Layout Manager? a object associated with a container

which governs the placement and size of the component

All containers whether top-level or general-purpose

are based on a Layout Manager.

JFrame, JApplet has BorderLayout by default

Why needs Layout Manager?

Normal not Layout Manager: Set an absolute size for components

What happens when the user resize a window? How does my component look like?

How you guys solve platform-dependent positioning?

Okay. Layout Manager takes care of this for you.

LayoutManager based on

minimumSize, preferedSize, maximumSize

to resize and arrange components on the screen

Steps for using Layout Managers 1. setLayout()

Container contentPane = frame.getContentPane(); contentPane.setLayout(new BoxLayout(contentPane, BoxLayout.X_AXIS));

Steps for using Layout Managers 2. specify size | void setPreferredSize(Dimension preferredSize)

| void setMinimumSize(Dimension minimumSize)

| void setMaximumSize(Dimension maximumSize)

| btnOk.setPreferredSize(new Dimension (20,20))

Steps for using Layout Managers

3. pack()

4. setVisible()

Types of Layout Manager

FlowLayout

BorderLayout

Types of Layout Manager

GridLayout

CardLayout

FlowLayout Constructors public FlowLayout()

public FlowLayout(int alignment)

public FlowLayout(int alignment, int hgap, int vgap)

FlowLayout Alignments: CENTER

LEADING

LEFT

RIGHT

TRAILING

FlowLayout Benefits Simple to use

Centers layout for bigger container

Suitable for JApplet

FlowLayout Drawbacks Resize loose alignment

No complex alighment

BorderLayout by default in center

BorderLayout Alignment

AFTER_LAST_LINE, PAGE_END, SOUTH

AFTER_LINE_ENDS, LINE_END, EAST

BEFORE_FIRST_LINE, PAGE_START, NORTH

BEFORE_LINE_BEGINS, LINE_START, WEST

CENTER

BorderLayout Constructor public BorderLayout()

public BorderLayout(int hgap, int vgap)

BorderLayout Adv. Can specify direction

Dis. Only five locations to add components

No high complexity

GridLayout setLayout(new GridLayout(3, 4))

GridLayout public GridLayout()

public GridLayout(int rows, int columns)

public GridLayout(int rows, int columns, int hgap, int vgap)

GridLayout Adv. Simple to use Useful for rectangular pattern

Same size component

Dis. Cannot create a complex layout

CardLayout

CardLayout CardLayout()

CardLayout(int horizontal_gap, int vertical_gap)

CardLayout

CardLayout void first(Container parent)

void next(Container parent)

void previous(Container parent)

void last(Container parent)

CardLayout Adv. Containers and their associated components to share the same space in the container

Dis. Not visually appealing as a Tabbed pane

Requires other components like buttons or drop-down to flip through