Lecture 19

JButton myButton = new JButton("x");
myListener m = new myListener;
myButton.addActionListener(m);
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/* can be replaced with below */
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myButton.addActionListener(new myListener());


public myJFrame()
{
super("title of Window");
.
.
.
JButton myButton = new JButton("title of button");
myButton.addActionListener( new myListener());
}

What happens when you have multiple buttons?

• Bad way
• define different listener classes for each button
• register the appropriate class to the appropriate button
• Good way
  
• examine e
• object of type ActionEvent
• ActionEvent has a method returning the label of the button pressed

public String getActionCommand()
/* Andrew drew a picture of two buttons labeled different things then pointed out that when you click the button "one" e.getActionCommand returns "One"*/

• These implement the interface LayoutManager
• BorderLayout
• FlowLayout
• GridLayout

• A window (JFrame) is a container
• allowed to contain objects and have layouts
• a window can be divided into regions using LayoutManager
• each region can be made into a container by declaring it a JPanel
• a panel is a Container

1. Declare a LayoutManager
1. setLayout(new BorderLayout());
2. Add a apanel to as many regions as you want
1. JPanel myPanel = new JPanel();
2. add(MyPanel, BorderLayout, North);
3. Declare a layout to the panel
1. myPanel.SetLayout(new.FlowLayout());