Win a copy of Design for the Mind this week in the Design forum!
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

The purpose of using getContentPane()

 
Griff Haldeman
Greenhorn
Posts: 5
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
What's the point of calling frame.getContentPane().add(button) when frame.add(button) works all the same? To my understanding, adding directly to the frame without first getting the content pane is disparaged, but if someone could elaborate on this, it'd be great.
 
Greg Charles
Sheriff
Posts: 2985
12
Firefox Browser IntelliJ IDE Java Mac Ruby
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
It's been awhile since I used Swing, but if I remember right, JFrame has an addImpl() method that adds components to the content pane by default. That's why frame.getContentPane.add(...) does the same thing as frame.add(...). As to why or if that's a bad practice, I'm not sure. Probably because you're not being explicit about what you're doing. There's a glass pane, where you can draw things that appear superimposed over what's in the content pane. Also a root pane and layered pane, but I forget what those do.
 
Griff Haldeman
Greenhorn
Posts: 5
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks, just what I wanted to know.
 
Rob Spoor
Sheriff
Pie
Posts: 20511
54
Chrome Eclipse IDE Java Windows
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
In Java 1.4 and before, adding components to a JFrame directly, or setting its layout directly, would result in an error (of java.lang.Error or some sub class, can't remember which one it was). You really needed to use the content pane. In Java 5.0 they decided it made more sense to just redirect those calls to the content pane.
 
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic