4 JProgressBar、ProgressMonitor、BoundedRangeModel实现进度条

进度条是图形界面中广泛使用的GUI组件，当复制一个较大的文件时，操作系统会显示一个进度条，用于标识复制操作完成的比例。

4.1 创建进度条

使用JProgressBar创建进度条的步骤：

1.创建JProgressBar对象

public JProgressBar(int orient,int min,int max);

orient:方向

2.设置属性

setBorderPainted(boolean b);设置进度条是否有边框

setIndeterminate(boolean newValue);设置当前进度条是不是进度不确定的进度条，如果是，则将看到一个滑块在进度条左右移动

setStringPainted(boolean b);设置进度条是否显示当前完成的百分比

3.获取和设置当前进度条的进度状态

setValue(int n);设置当前进度值

double getPercentComplete();获取进度条的完成百分比

String getString();返回进度字符串的当前值

案例：

使用JProgressBar完成下图效果：

public class JProgressTest {JFrame jf = new JFrame("测试进度条");JCheckBox indeterminate = new JCheckBox("不确定进度");JCheckBox noBorder = new JCheckBox("不绘制边框");//创建进度条JProgressBar bar = new JProgressBar(JProgressBar.HORIZONTAL,0,100);public void init(){//组装视图//处理复选框的点击行为indeterminate.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//获取一下indeterminate复选框有没有选中？boolean selected = indeterminate.isSelected();//设置当前进度条不确定进度bar.setIndeterminate(selected);bar.setStringPainted(!selected);}});noBorder.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//获取一下noBorder复选框有没有选中？boolean selected = noBorder.isSelected();bar.setBorderPainted(!selected);}});Box vBox = Box.createVerticalBox();vBox.add(indeterminate);vBox.add(noBorder);//设置进度条的属性bar.setStringPainted(true);bar.setBorderPainted(true);//把当前窗口的布局方式修改为FlowLayoutjf.setLayout(new FlowLayout());jf.add(vBox);jf.add(bar);jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);jf.pack();jf.setVisible(true);//通过循环模拟修改进度条的进度for (int i = 0; i <= 100; i++) {//修改已经完成的工作量，也就是百分比bar.setValue(i);try {Thread.sleep(500);} catch (InterruptedException e) {e.printStackTrace();}}}public static void main(String[] args) {new JProgressTest().init();}
}

这种耗时操作放在主线程的话，会导致执行耗时操作时，用户无法再进行任何操作，因此最好将耗时操作放入子线程中。

代码改进：

public class JProgressTest2 {JFrame jf = new JFrame("测试进度条");JCheckBox indeterminate = new JCheckBox("不确定进度");JCheckBox noBorder = new JCheckBox("不绘制边框");//创建进度条JProgressBar bar = new JProgressBar(JProgressBar.HORIZONTAL,0,100);public void init(){//组装视图//处理复选框的点击行为indeterminate.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//获取一下indeterminate复选框有没有选中？boolean selected = indeterminate.isSelected();//设置当前进度条不确定进度bar.setIndeterminate(selected);bar.setStringPainted(!selected);}});noBorder.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//获取一下noBorder复选框有没有选中？boolean selected = noBorder.isSelected();bar.setBorderPainted(!selected);}});Box vBox = Box.createVerticalBox();vBox.add(indeterminate);vBox.add(noBorder);//设置进度条的属性bar.setStringPainted(true);bar.setBorderPainted(true);//把当前窗口的布局方式修改为FlowLayoutjf.setLayout(new FlowLayout());jf.add(vBox);jf.add(bar);jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);jf.pack();jf.setVisible(true);//开启子线程，模拟耗时操作SimulaterActivity simulaterActivity = new SimulaterActivity(bar.getMaximum());new Thread(simulaterActivity).start();//设置一个定时任务Timer timer = new Timer(200, new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//读取线程任务对象的当前完成量，设置给进度条int current = simulaterActivity.getCurrent();bar.setValue(current);}});timer.start();//监听进度条的任务变化bar.addChangeListener(new ChangeListener() {@Overridepublic void stateChanged(ChangeEvent e) {int value = bar.getValue();if (value == simulaterActivity.getAmount()){timer.stop();}}});}private class SimulaterActivity implements  Runnable{//记录任务总量private int amount;//记录当前任务的完成量private volatile int current;public SimulaterActivity(int amount) {this.amount = amount;}public int getAmount() {return amount;}public void setAmount(int amount) {this.amount = amount;}public int getCurrent() {return current;}public void setCurrent(int current) {this.current = current;}@Overridepublic void run() {//子线程的任务  模拟耗时操作while(current<amount){try {Thread.currentThread().sleep(50);} catch (InterruptedException e) {e.printStackTrace();}current++;}}}public static void main(String[] args) {new JProgressTest2().init();}
}

之前我们学习过，Swing中很多组件的界面与数据都采用了MVC的设计思想：

Swing组件大都将外观显示和内部数据分离，JProgressBar也不例外，JProgressBar组件有一个内置的用于保存其状态数据的Model对象，这个对象由BoundedRangeModel对象表示，程序调用JProgressBar对象的方法完成进度百分比的设置，监听进度条的数据变化，其实都是通过它内置的BoundedRangeModel对象完成的。下面的代码是对之前代码的改进，通过BoundedRangeModel完成数据的设置，获取和监听。

public class JProgressTest3 {JFrame jf = new JFrame("测试进度条");JCheckBox indeterminate = new JCheckBox("不确定进度");JCheckBox noBorder = new JCheckBox("不绘制边框");//创建进度条JProgressBar bar = new JProgressBar(JProgressBar.HORIZONTAL,0,100);//获取处进度条内置的数据模型对象BoundedRangeModel model = bar.getModel();public void init(){//组装视图//处理复选框的点击行为indeterminate.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//获取一下indeterminate复选框有没有选中？boolean selected = indeterminate.isSelected();//设置当前进度条不确定进度bar.setIndeterminate(selected);bar.setStringPainted(!selected);}});noBorder.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//获取一下noBorder复选框有没有选中？boolean selected = noBorder.isSelected();bar.setBorderPainted(!selected);}});Box vBox = Box.createVerticalBox();vBox.add(indeterminate);vBox.add(noBorder);//设置进度条的属性bar.setStringPainted(true);bar.setBorderPainted(true);//把当前窗口的布局方式修改为FlowLayoutjf.setLayout(new FlowLayout());jf.add(vBox);jf.add(bar);jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);jf.pack();jf.setVisible(true);//开启子线程，模拟耗时操作SimulaterActivity simulaterActivity = new SimulaterActivity(bar.getMaximum());new Thread(simulaterActivity).start();//设置一个定时任务Timer timer = new Timer(200, new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//读取线程任务对象的当前完成量，设置给进度条int current = simulaterActivity.getCurrent();//bar.setValue(current);model.setValue(current);}});timer.start();//监听进度条的任务变化model.addChangeListener(new ChangeListener() {@Overridepublic void stateChanged(ChangeEvent e) {int value = model.getValue();if (value == simulaterActivity.getAmount()){timer.stop();}}});}private class SimulaterActivity implements  Runnable{//记录任务总量private int amount;//记录当前任务的完成量private volatile int current;public SimulaterActivity(int amount) {this.amount = amount;}public int getAmount() {return amount;}public void setAmount(int amount) {this.amount = amount;}public int getCurrent() {return current;}public void setCurrent(int current) {this.current = current;}@Overridepublic void run() {//子线程的任务  模拟耗时操作while(current<amount){try {Thread.currentThread().sleep(50);} catch (InterruptedException e) {e.printStackTrace();}current++;}}}public static void main(String[] args) {new JProgressTest2().init();}
}

4.2 创建进度对话框

ProgressMonitor的用法与JProgressBar基本相似，只是ProgressMonitor可以直接创建一个进度对话框，它提供了下面的构造器完成对话框的创建：

public ProgressMonitor(Component parentcomponent,Object message,String note,int min,int max);

parentcomponent：对话框的描述信息

note：进度的提示信息

使用ProgressMonitor创建的对话框里包含的进度条是非常固定的，程序甚至不能设置该进度条是否包含边框（总是包含边框），不能设置进度不确定，不能改变进度条的方向（总是水平方向）。

案例：

使用ProgressMonitor完成下图效果：

public class ProgressMonitorTest {Timer timer;public void init(){//创建进度对话框ProgressMonitor monitor = new ProgressMonitor(null,"等待任务完成","已完成",0,100);SimulaterActivity simulaterActivity = new SimulaterActivity(100);new Thread(simulaterActivity).start();//设置定时任务timer = new Timer(200, new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//读取当前任务量，修改进度int current = simulaterActivity.getCurrent();monitor.setProgress(current);//判断用户是否点击了取消按钮，停止定时任务，关闭对话框，退出程序if (monitor.isCanceled()){timer.stop();monitor.close();System.exit(0);}}});timer.start();}public static void main(String[] args) {new ProgressMonitorTest().init();}//定义一个线程任务，模拟耗时操作private class SimulaterActivity implements Runnable{//内存可见private volatile int current = 0;private int amount;public SimulaterActivity(int amount) {this.amount = amount;}public int getCurrent() {return current;}public void setCurrent(int current) {this.current = current;}public int getAmount() {return amount;}public void setAmount(int amount) {this.amount = amount;}@Overridepublic void run() {//通过循环，不断的修改current的值，模拟任务完成量while(current<amount){try {Thread.sleep(50);} catch (InterruptedException e) {e.printStackTrace();}current++;}}}}