java.awt BorderLayout and FlowLayout

[Anonymous]

why doesn't this show the center button occuping the whole window???

  
import java.awt.*; 
 public class TestFrame extends Frame 
 { 
      Button bNorth = new Button("North"); 
      Button bSouth = new Button("South"); 
      Button bEast = new Button("East"); 
      Button bWest = new Button("West"); 
      Button bCenter = new Button("Center"); 
 
      public TestFrame() 
      { 
           setLayout(new FlowLayout()); 
           add(bNorth); 
           add(bSouth); 
           add(bWest); 
           add(bEast); 
           add(bCenter); 
           setLayout(new BorderLayout()); 
           validate(); 
           setSize(300,300); 
           setVisible(true); 
      }
      public static void main(String args[]) 
      { 
           TestFrame tf = new TestFrame(); 
      }
}

Thanks!!!

[Jose Botella]

I think BorderLayout is the only LayoutManager that doesn't know how to reorder previously added components.
Also after executing it, I don't see any button.

[Manfred Leonhardt]

Hi Amish,
The example points out the difference between LayoutManager and LayoutManager2 interfaces. All objects that implement LayoutManager2 require constraints to perform the actual layout. No constraints = no layout = no visible objects!
The following layouts implement LayoutManager2:
CardLayout, GridBagLayout, BorderLayout, and BoxLayout
This is also another reason why the layout should be set first and then components inserted into it. Then the problem will not be an issue at all!
Regards,
Manfred.

[Anonymous]

Hi Manfred
Thanks a lot that clears the difference.
Amish