Oop lecture9 10

Lecture 10
Swing layouts

Object Oriented Programming
Eastern University, Dhaka
Md. Raihan Kibria

Specifying no layout in JFrame
public class DefaultLayoutDemo {

public static void main(String[] args) {
JFrame frame = new JFrame("DefaultLayoutDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//Set up the content pane.
frame.add(new JButton("a"));
frame.add(new JButton("b"));

//Display the window.
frame.pack();
frame.setVisible(true);
}
}

Specifying positions of controls
public class DefaultLayoutDemo {

JFrame frame = new JFrame("DefaultLayoutDemo");

//Set up the content pane.
frame.add(new JButton("a"), BorderLayout.NORTH);
frame.add(new JButton("b"), BorderLayout.SOUTH);

//Display the window.
frame.pack();
}
}

The default layout for JFrame is
BorderLayout

BorderLayout
public class BorderLayoutDemo {

public static boolean RIGHT_TO_LEFT = false;
public static void addComponentsToPane(Container pane) {

if (RIGHT_TO_LEFT) {
pane.setComponentOrientation(
java.awt.ComponentOrientation.RIGHT_TO_LEFT);
}

JButton button = new JButton("Button 1 (PAGE_START)");
pane.add(button, BorderLayout.PAGE_START);

button = new JButton("Button 2 (CENTER)");
button.setPreferredSize(new Dimension(200, 100));
pane.add(button, BorderLayout.CENTER);

button = new JButton("Button 3 (LINE_START)");
pane.add(button, BorderLayout.LINE_START);

button = new JButton("Long-Named Button 4 (PAGE_END)");
pane.add(button, BorderLayout.PAGE_END);

button = new JButton("5 (LINE_END)");
pane.add(button, BorderLayout.LINE_END);
}

JFrame frame = new JFrame("BorderLayoutDemo");
addComponentsToPane(frame.getContentPane());
frame.pack();
}
}

If you stretch the frame the center part gets filled by the control in it

BoxLayout
public class BoxLayoutDemo {
pane.setLayout(new BoxLayout(pane, BoxLayout.Y_AXIS));
addAButton("Button 1", pane);
addAButton("Long-Named Button 4", pane);
addAButton("5", pane);
}

private static void addAButton(String text, Container container) {
JButton button = new JButton(text);
button.setAlignmentX(Component.CENTER_ALIGNMENT);
container.add(button);
}

JFrame frame = new JFrame("BoxLayoutDemo");
frame.pack();
}
}

Result

There is no resizing when the frame is stretched out

FlowLayout
public class FlowLayoutDemo extends JFrame{
FlowLayout experimentLayout = new FlowLayout();

public FlowLayoutDemo(String name) {
super(name);
}

public void addComponentsToPane(final Container pane) {
JPanel compsToExperiment = new JPanel();
compsToExperiment.setLayout(experimentLayout);
experimentLayout.setAlignment(FlowLayout.LEADING);

//Add buttons to the experiment layout
compsToExperiment.add(new JButton("Button 1"));
compsToExperiment.add(new JButton("Long-Named Button 4"));
compsToExperiment.add(new JButton("5"));
//Left to right component orientation is selected by default
compsToExperiment.setComponentOrientation(
ComponentOrientation.LEFT_TO_RIGHT);

pane.add(compsToExperiment, BorderLayout.CENTER);
}

FlowLayoutDemo frame = new FlowLayoutDemo("FlowLayoutDemo");
frame.addComponentsToPane(frame.getContentPane());
frame.pack();
}
}

If we stretch the controls are still pinned to the left because
of this:
experimentLayout.setAlignment(FlowLayout.LEADING);

GridLayout
public class GridLayoutDemo {

pane.setLayout(new GridLayout(3, 2));
JButton b1 = new JButton("First");
pane.add(b1);
b1 = new JButton("Second");
pane.add(b1);
b1 = new JButton("Third");
pane.add(b1);
b1 = new JButton("Fourth");
pane.add(b1);
b1 = new JButton("Fifth");
pane.add(b1);
b1 = new JButton("Sixth");
pane.add(b1);
}


JFrame frame = new JFrame("GridBagLayoutDemo");
frame.pack();
}

Result

3 columns and 2 rows as set in:
pane.setLayout(new GridLayout(3, 2));

GridBagLayout
public class GridBagLayoutDemo {


JButton button;
pane.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();

button = new JButton("Button 1");
c.gridx = 0;
c.gridy = 0;
pane.add(button, c);

c.gridx = 1;
c.gridy = 0;

c.gridx = 2;
c.gridy = 0;

button = new JButton("Long-Named Button 4");
c.gridx = 0;
c.gridy = 1;

button = new JButton("5");
c.gridx = 1;
c.gridy = 2;
}

JFrame frame = new JFrame("GridBagLayoutDemo");
frame.pack();
}
}

GridBagLayout is very flexible layout

Questions
 What is the most flexible of these layouts
 Whichone is easy to implement
 Which layout to choose when you want
your control to take up as much space as
possible

 Interested in more? -
 GroupLayout
 SpringLayout

Oop lecture9 10

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