



Border Layout


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The Border layout manager is a little odd and not exactly what you'd
expect in a layout manager, BUT, nonetheless, the designers of Java decided
to make it the default layout manager for Frames.
While the Flow layout manager always honors a component's preferred size and
the Grid layout manager never does, the Border layout manager does something
in between.

The Border layout manager divides its territory into five regions. The names
of these regions are North, South, East, West, and Center. Each region
may contain a single component (but no region is required to contain a
component).

import java.awt.*;
import java.applet.*;

public class border extends Applet{
  public void init(){
    setBackground(Color.yellow);
    setLayout(new BorderLayout());
    setFont(new Font("Serif", Font.BOLD, 24));
    add(new Label("North"), BorderLayout.NORTH);
    add(new Label("South"), BorderLayout.SOUTH);
    add(new Label("West"), BorderLayout.WEST);
    add(new Label("East"), BorderLayout.EAST);
    add(new Label("Center"), BorderLayout.CENTER);
  /*ALTERNATIVE SYNTAX:
    add("North", new Label("North"));
    add("South", new Label("South"));
    add("West", new Label("West"));
    add("East", new Label("East"));
    add("Center", new Label("Center"));
  */
  }
}

//<applet code=border.class height=120 width=120></applet>






In this applet each of the five regions contain one label with the
appropriate name. Study the code to see how components are added.
Notice that the alignment within the areas isn't centered.

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Room For Only One: How many components can be added to a single
region using borderLayout? Well there are two ways of looking at it. Strictly
speaking only one component may be added to a single region. As an example
consider the following applet in which two labels are added to the same
region (center). Only one shows up!


import java.awt.*;
import java.applet.*;

public class oneA extends Applet{
  public void init(){
    setBackground(Color.yellow);
    setLayout(new BorderLayout());
    add(new Label("ONE"), BorderLayout.CENTER);
    add(new Label("TWO"), BorderLayout.CENTER);
  }
}
//<applet code=oneA.class height=120 width=120></applet>








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Using Panels: The way to get more than one component into
a single region is to place the components on a panel and then add the
panel to the region. Here's an example:


import java.awt.*;
import java.applet.*;

public class pan extends Applet{
  public void init(){
    setForeground(Color.cyan);
    setLayout(new BorderLayout());
    Panel one = new Panel();
    one.setBackground(Color.red);
    Label L = new Label("Panel Demo");
    L.setFont(new Font("Serif", Font.BOLD, 36));
    one.add(L);
    add(one, BorderLayout.NORTH);
    Panel two = new Panel();
    two.setBackground(Color.black);
    two.setLayout(new GridLayout(3,1));
    two.setFont(new Font("Serif", Font.BOLD, 18));
    Label L1=new Label("Bananas");
    Label L2=new Label("Apples");
    Label L3=new Label("Oranges");
    L1.setForeground(Color.yellow);
    L2.setForeground(Color.yellow);
    L3.setForeground(Color.yellow);
    two.add(L1);
    two.add(L2);
    two.add(L3);
    add(two, BorderLayout.WEST);
    Panel three = new Panel();
    three.setLayout(new GridLayout(3,1));
    three.setBackground(Color.blue);
    TextField t1 = new TextField("Enter amount");
    TextField t2 = new TextField("Enter amount");
    TextField t3 = new TextField("Enter amount");
    three.add(t1);
    three.add(t2);
    three.add(t3);
    add(three,BorderLayout.CENTER);
    Panel four = new Panel();
    four.setLayout(new GridLayout(3,1));
    four.setBackground(Color.green);
    Button b1 = new Button("BUY bananas");
    Button b2 = new Button("BUY apples");
    Button b3 = new Button("BUY oranges");
    b1.setBackground(Color.green);
    b2.setBackground(Color.green);
    b3.setBackground(Color.green);
    four.add(b1);
    four.add(b2);
    four.add(b3);
    add(four,BorderLayout.EAST);
    Panel five = new Panel();
    five.setBackground(Color.magenta);
    five.add(new TextArea(5,40));
    add(five,BorderLayout.SOUTH);
  }
}
//<applet code=pan.class height=300 width=400></applet>