Frame.
Everything you need to create and work with frames is contained in the java.awt.Frame class.
To create a new frame
without a title bar use the Frame() constructor with no arguments.
Frame f = new Frame();
Frame f = new Frame("My Window");
java.awt.Container so you can add components to a frame. Unlike panels and applets, the default LayoutManager for a frame is BorderLayout, not FlowLayout. However you can change this using the frame's setLayout() method like this:
f.setLayout(new FlowLayout());
java.awt.Component so they have paint() and update() methods. If you want to draw in the frame and process events manually like you did in applets,
just create a subclass of Frame and add listener objects
to it. Almost everything you did in those chapters with a user-defined subclass of java.awt.Applet can also be done with a user-defined subclass of java.awt.Frame.
However most of the time you'll prefer to use components. To add a component to a
frame call the frame's add() method just as you would call an applet's add() method. The only difference is that you may often call the add() method from outside the Frame class so you'll need to prefix add with a variable that points to the frame
and the member operator . In other words given a Frame f, you need to call
f.add(new Button("OK");
this.add(new Button("OK"));
add(). If you're calling add() from one of the Frame subclass's own methods you won't need to do this.
Since the default layout for a frame
is BorderLayout, you should specify whether you want the component added to the North, South, East, West or Center. Here's how you'd add a centered label to the center of Frame f:
f.add("Center", new Label("This is a frame", Label.CENTER));
setSize() method like this
f.setSize(150,150);
Frame's title bar call its insets() method and look at the top member of the resulting java.awt.Insets object. That will be the height of the title bar. That is,
int TitleBarHeight = f.insets().top;
Frame to the proper place on the screen takes a little more effort. You move a Frame with the setLocation(int x, int y) method. However x and y are relative to the screen, not to the applet.
When a window is first created, it's invisible. Add components to the Frame while it's still invisible. The effect of Buttons, Labels and other widgets popping onto a layout in rapid succession while the window jumps around and changes size can be quite disconcerting. When you're done adding components, resizing and moving the Frame, make it visible by calling its show() method like so:
f.show();