疯狂JAVA讲义---第十二章：Swing编程（五）进度条和滑动条

前几天讲了Swing基本的控件，今天开始讲特殊控件。一天讲2个吧，首先讲用JProgressBar，ProgressMonitor和BoundedRangeModel来实现进度条。然后讲用JSlider和BoundedRangeModel来实现滑动条。

进度条，eg

public class TestJProgressBar
{
JFrame frame = new JFrame("测试进度条");
//创建一条垂直进度条
JProgressBar bar = new JProgressBar(JProgressBar.VERTICAL );
JCheckBox indeterminate = new JCheckBox("不确定进度");
JCheckBox noBorder = new JCheckBox("不绘制边框");
public void init()
{
Box box = new Box(BoxLayout.Y_AXIS);
box.add(indeterminate);
box.add(noBorder);
frame.setLayout(new FlowLayout());
frame.add(box);
//把进度条添加到JFrame窗口中
frame.add(bar);

//设置在进度条中绘制完成百分比
bar.setStringPainted(true);
noBorder.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
//根据该选择框决定是否绘制进度条的边框
bar.setBorderPainted(!noBorder.isSelected());
}
});
final SimulatedTarget target = new SimulatedTarget(1000);
//以启动一条线程的方式来执行一个耗时的任务
new Thread(target).start();
//设置进度条的最大值和最小值,
bar.setMinimum(0);
//以总任务量作为进度条的最大值
bar.setMaximum(target.getAmount());
Timer timer = new Timer(300 , new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
//以任务的当前完成量设置进度条的value
bar.setValue(target.getCurrent());
}
});
timer.start();
indeterminate.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
//设置该进度条的进度是否确定
bar.setIndeterminate(indeterminate.isSelected());
bar.setStringPainted(!indeterminate.isSelected());
}
});
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args)
{
new TestJProgressBar().init();
}
}
//模拟一个耗时的任务
class SimulatedTarget implements Runnable
{
//任务的当前完成量
private volatile int current;
//总任务量
private int amount;
public SimulatedTarget(int amount)
{
current = 0;
this.amount = amount;
}

public int getAmount()
{
return amount;
}

public int getCurrent()
{
return current;
}
//run方法代表不断完成任务的过程
public void run()
{

while (current < amount)
{
try
{
Thread.sleep(50);
}
catch(InterruptedException e)
{

}
current++;
}
}
}

SimulatedTarget模拟了一个耗时程序，JProgressBar存在BoundedRangeModel用于保存数据对象。ProgressMonitor是进度对话框，用起来很方便，但就缺乏了自主性，eg

public class TestProgressMonitor
{
Timer timer;
public void init()
{
final SimulatedTarget target = new SimulatedTarget(1000);
//以启动一条线程的方式来执行一个耗时的任务
final Thread targetThread = new Thread(target);
targetThread.start();
//创建进度对话框
final ProgressMonitor dialog = new ProgressMonitor(null ,
"等待任务完成" , "已完成：" , 0 , target.getAmount());
//创建一个计时器
timer = new Timer(300 , new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
//以任务的当前完成量设置进度对话框的完成比例
dialog.setProgress(target.getCurrent());
//如果用户单击了进度对话框的”取消“按钮
if (dialog.isCanceled())
{
//停止计时器
timer.stop();
//中断任务的执行线程
targetThread.interrupt();
//系统退出
System.exit(0);
}
}
});
timer.start();
}
public static void main(String[] args)
{
new TestProgressMonitor().init();
}
}

这个程序利用了上面的耗时程序。进度条就是那么简单。

滑动条和进度条差不多，他们共用一个模型BoundedRangeModel。下面是个滑动条的各样式的演示例子，eg

public class TestJSlider
{
JFrame mainWin = new JFrame("滑动条示范");
Box sliderBox = new Box(BoxLayout.Y_AXIS);
JTextField showVal = new JTextField();
ChangeListener listener;
public void init()
{
//定义一个监听器，用于监听所有滑动条
listener = new ChangeListener()
{
public void stateChanged(ChangeEvent event)
{
//取出滑动条的值，并在文本中显示出来
JSlider source = (JSlider) event.getSource();
showVal.setText("当前滑动条的值为：" + source.getValue());
}
};
//-----------添加一个普通滑动条-----------
JSlider slider = new JSlider();
addSlider(slider, "普通滑动条");

//-----------添加保留区为30的滑动条-----------
slider = new JSlider();
slider.setExtent(30);
addSlider(slider, "保留区为30");

//-----------添加带主、次刻度的滑动条,并设置其最大值，最小值-----------
slider = new JSlider(30 , 200);
//设置绘制刻度
slider.setPaintTicks(true);
//设置主、次刻度的间距
slider.setMajorTickSpacing(20);
slider.setMinorTickSpacing(5);
addSlider(slider, "有刻度");

//-----------添加滑块必须停在刻度处滑动条-----------
slider = new JSlider();
//设置滑块必须停在刻度处
slider.setSnapToTicks(true);
//设置绘制刻度
slider.setPaintTicks(true);
//设置主、次刻度的间距
slider.setMajorTickSpacing(20);
slider.setMinorTickSpacing(5);
addSlider(slider, "滑块停在刻度处");

//-----------添加没有滑轨的滑动条-----------
slider = new JSlider();
//设置绘制刻度
slider.setPaintTicks(true);
//设置主、次刻度的间距
slider.setMajorTickSpacing(20);
slider.setMinorTickSpacing(5);
//设置不绘制滑轨
slider.setPaintTrack(false);
addSlider(slider, "无滑轨");

//-----------添加方向反转的滑动条-----------
slider = new JSlider();
//设置绘制刻度
slider.setPaintTicks(true);
//设置主、次刻度的间距
slider.setMajorTickSpacing(20);
slider.setMinorTickSpacing(5);
//设置方向反转
slider.setInverted(true);
addSlider(slider, "方向反转");

//-----------添加绘制默认刻度标签的滑动条-----------
slider = new JSlider();
//设置绘制刻度
slider.setPaintTicks(true);
//设置主、次刻度的间距
slider.setMajorTickSpacing(20);
slider.setMinorTickSpacing(5);
//设置绘制刻度标签，默认绘制数值刻度标签
slider.setPaintLabels(true);
addSlider(slider, "数值刻度标签");

//-----------添加绘制Label类型的刻度标签的滑动条-----------
slider = new JSlider();
//设置绘制刻度
slider.setPaintTicks(true);
//设置主、次刻度的间距
slider.setMajorTickSpacing(20);
slider.setMinorTickSpacing(5);
//设置绘制刻度标签
slider.setPaintLabels(true);
Dictionary<Integer, Component> labelTable = new Hashtable<Integer, Component>();
labelTable.put(0, new JLabel("A"));
labelTable.put(20, new JLabel("B"));
labelTable.put(40, new JLabel("C"));
labelTable.put(60, new JLabel("D"));
labelTable.put(80, new JLabel("E"));
labelTable.put(100, new JLabel("F"));
//指定刻度标签，标签是JLabel
slider.setLabelTable(labelTable);
addSlider(slider, "JLable标签");

//-----------添加绘制Label类型的刻度标签的滑动条-----------
slider = new JSlider();
//设置绘制刻度
slider.setPaintTicks(true);
//设置主、次刻度的间距
slider.setMajorTickSpacing(20);
slider.setMinorTickSpacing(5);
//设置绘制刻度标签
slider.setPaintLabels(true);
labelTable = new Hashtable<Integer, Component>();
labelTable.put(0, new JLabel(new ImageIcon("ico/0.GIF")));
labelTable.put(20, new JLabel(new ImageIcon("ico/2.GIF")));
labelTable.put(40, new JLabel(new ImageIcon("ico/4.GIF")));
labelTable.put(60, new JLabel(new ImageIcon("ico/6.GIF")));
labelTable.put(80, new JLabel(new ImageIcon("ico/8.GIF")));
//指定刻度标签，标签是ImageIcon
slider.setLabelTable(labelTable);
addSlider(slider, "Icon标签");

mainWin.add(sliderBox, BorderLayout.CENTER);
mainWin.add(showVal, BorderLayout.SOUTH);
mainWin.pack();
mainWin.setVisible(true);

}
//定义一个方法，用于将滑动条添加到容器中
public void addSlider(JSlider slider, String description)
{
slider.addChangeListener(listener);
Box box = new Box(BoxLayout.X_AXIS);
box.add(new JLabel(description + "："));
box.add(slider);
sliderBox.add(box);
}

public static void main(String[] args)
{
new TestJSlider().init();
}
}