Swing
Frames
Toolkit class
Two methods of the Toolkit class
| Method | Description |
|---|---|
| getDefaultToolkit() | A static method that returns the Toolkit object for the current system. |
| getScreenSize() | Returns the screen resolution as a Dimension object. |
Two fields of the Dimension class
| Field | Description |
|---|---|
| height | Stores the height of this Dimension object as an int. |
| width | Stores the width of this Dimension object as an int. |
How to center a frame using the Toolkit class
- The number of pixels per screen varies depending on the resolution setting of the user's monitor.
- To determine the number of pixels for the current screen, you can use a Toolkit object, or toolkit, to return a Dimension object that contains the number of pixels for the current screen.
- The Toolkit and Dimension classes are in the java.awt package.
A method that centers a frame on the screen
private void centerWindow(Window w)
{
Toolkit tk = Toolkit.getDefaultToolkit();
Dimension d = tk.getScreenSize();
setLocation((d.width-w.getWidth())/2,
(d.height-w.getHeight())/2);
}
The constructor for a class that defines a centered frame
FutureValueFrame()
{
setTitle("Future Value Calculator");
setSize(267, 200);
centerWindow(this);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}