Learning Java

Scrollbars and Sliders

JScrollPane is such a handy component that you may not ever need to use scrollbars by themselves. In fact, if you ever do find yourself using a scrollbar by itself, chances are you really want to use another component called a slider.

There’s not much point in describing the appearance and functionality of scrollbars and sliders. Instead, let’s jump right in with an example that includes both components. Figure 14.9 shows a simple example with both a scrollbar and a slider.

Figure 14-9. Using a scrollbar and a slider

Here is the source code for this example:

//file: Slippery.java import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; public class Slippery extends JFrame { public Slippery( ) { super("Slippery v1.0"); setSize(220, 160); setLocation(200, 200); Container content = getContentPane( ); JPanel main = new JPanel(new GridLayout(2, 1)); JPanel scrollBarPanel = new JPanel( ); final JScrollBar scrollBar = new JScrollBar(JScrollBar.HORIZONTAL, 0, 48, 0, 255); int height = scrollBar.getPreferredSize( ).height; scrollBar.setPreferredSize(new Dimension(175, height)); scrollBarPanel.add(scrollBar); main.add(scrollBarPanel); JPanel sliderPanel = new JPanel( ); final JSlider slider = new JSlider(JSlider.HORIZONTAL, 0, 255, 128); slider.setMajorTickSpacing(48); slider.setMinorTickSpacing(16); slider.setPaintTicks(true); sliderPanel.add(slider); ...