第11章 进度条、滑杆和分隔条

 

第11章 进度条、滑杆和分隔条

　　本章介绍三个Swing组件：JProgressBar、JSlider和JSeparator。
　　人们经常用进度条反映耗时任务已完成的百分比，本章将提供这样一个例子。但是，用ProgressMonitor和ProgressMonitorInputStream实用工具来反映一个任务的进度信息通常会更容易。“进度监控”小节中讨论了ProgressMonitor和ProgressMonitorInputStream实用工具。
　　JProgressBar和JSlider与JSeparator一样，用来描述一个介于最小值和最大值之间的值。因此，与JProgressBar和JSlider相关的模型是BoundedRangeModel接口的一个实现。
　　JSeparator是绘制一条蚀刻线的组件，它把逻辑上相关的组件分隔在一组，JSeparator组件可水平地垂直地放置。

11.1 JProgressBar

　　JProgressBar是一个简单的组件，它一般是一种颜色部分或完全填充的矩形。缺省情况下，进度条配备了一个凹陷的边框，并水平放置。
　　进度条还可以选择显示一个字符串，这个字符串在进度条矩形的中央位置上显示。这个字符串缺省时为耗时任务已完成的百分比。这个字符串可用JProgressBar.setString方法定制。
　　图11-1中示出的小应用程序创建了不同配置的进度条。
　　例11-1列出了图11-1中示出的小应用程序的代码。

例11-1 各种配置的进度条

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {
private JProgressBar[] progressBars = {
new JProgressBar(),
new JProgressBar(),
new JProgressBar(),
new JProgressBar()
};

public void init() {
Container contentPane = getContentPane();

contentPane.setLayout(new FlowLayout());

for(int i=0; i < progressBars.length; ++i) {
JProgressBar pb = progressBars[i];

if(i == 0) {
pb.setStringPainted(true);
pb.setString("Custom String");
}
if(i == 1) {
pb.setOrientation(JProgressBar.VERTICAL);
pb.setForeground(Color.yellow);
pb.setMaximum(1000);
pb.setValue(50);
pb.setBorder(
BorderFactory.createRaisedBevelBorder());
}
if(i == 2) {
pb.setForeground(Color.blue);
pb.setBorderPainted(false);
pb.setValue(50);
pb.setStringPainted(true);
}
if(i == 3) {
pb.setOrientation(JProgressBar.VERTICAL);
pb.setForeground(Color.red);
pb.setValue(90);
pb.setStringPainted(true);
pb.setBorder(
BorderFactory.createEtchedBorder());
}
contentPane.add(pb);
}
}
}

　　这个小应用程序创建了一组进度条，并为每个进度条设置了各种不同的属性，从而产生了图11-1中示出的各种不同配置。

11.1.1 进度条与线程

 

例11-2 使用JProgressBar

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {
private JProgressBar progressBar = new JProgressBar();
private JButton startButton = new JButton("start");

public void init() {
Container contentPane = getContentPane();

contentPane.setLayout(new FlowLayout());
contentPane.add(startButton);
contentPane.add(progressBar);

progressBar.setStringPainted(true);

startButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
(new UpdateThread()).start();
}
});
}
class UpdateThread extends Thread {
Runnable update, finish;
int value, min, max, increment;

public UpdateThread() {
max = progressBar.getMaximum();
min = progressBar.getMinimum();

update = new Runnable() {
public void run() {
value = progressBar.getValue() + increment;
updateProgressBar(value);
}
};
finish = new Runnable() {
public void run() {
updateProgressBar(min);
}
};
}
public void run() {
startButton.setEnabled(false);

while(value + increment <= max) {
simulateTimeConsumingActivity();
SwingUtilities.invokeLater(update);
}
SwingUtilities.invokeLater(finish);
startButton.setEnabled(true);
}
private void updateProgressBar(int value) {
progressBar.setValue(value);
}
private void simulateTimeConsumingActivity() {
try {
Thread.currentThread().sleep(1000);
increment = (max - min) / 10;
}
catch(InterruptedException e) {
e.printStackTrace();
}
}
}
}

11.1.2 JProgressBar属性

 

11.1.3 JProgressBar事件

 

例11-3 监视一个进度条的值

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {
private JProgressBar pb = new JProgressBar();

public void init() {
Container contentPane = getContentPane();
final JButton startButton = new JButton("start");

contentPane.setLayout(new FlowLayout());
contentPane.add(startButton);
contentPane.add(pb);

startButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
(new GetInfoThread(pb)).start();
}
});
pb.addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent e) {
int min = pb.getMinimum(), max = pb.getMaximum();
int value = pb.getValue();

showStatus("Min: " + min + ", Max: " + max +
", Value: " + value);
}
});
}
}
class GetInfoThread extends Thread {
Runnable update, finish;
JProgressBar pb;
int value, min, max, increment;

public GetInfoThread(JProgressBar progressBar) {
pb = progressBar;

max = pb.getMaximum();
min = pb.getMinimum();

update = new Runnable() {
public void run() {
value = pb.getValue() + increment;
pb.setValue(value);
}
};
finish = new Runnable() {
public void run() {
value = min;
pb.setValue(value);
}
};
}
public void run() {
while(value + increment <= max) {
simulateTimeConsumingActivity();
SwingUtilities.invokeLater(update);
}
SwingUtilities.invokeLater(finish);
}
private void simulateTimeConsumingActivity() {
try {
Thread.currentThread().sleep(1000);
increment = (max - min) / 10;
}
catch(InterruptedException e) {
e.printStackTrace();
}
}
}

11.1.4 JProgressBar类总结

 

11.1.5 AWT兼容

 

11.2 JSlider

 

例11-4 一个简单的JSlider例子

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;

public class Test extends JApplet {
public void init() {
Container contentPane = getContentPane();
JSlider slider = new JSlider();

contentPane.add(slider, BorderLayout.NORTH);
}
}

11.2.1 填充的滑杆

 

例11-5 一个填充的滑杆

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Test extends JApplet {
public Test() {
Container contentPane = getContentPane();
JSlider slider = new JSlider();

slider.putClientProperty("JSlider.isFilled",Boolean.TRUE);

contentPane.add(slider, BorderLayout.NORTH);
}
}

11.2.2 滑杆间隔标记

 

例11-6 显示滑杆的间隔标记

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;

public class Test extends JApplet {
public void init() {
Container contentPane = getContentPane();
JSlider slider = new JSlider();
JPanel controlPanel = new ControlPanel(slider);

contentPane.setLayout(new BorderLayout(0,40));
contentPane.add(controlPanel, BorderLayout.NORTH);
contentPane.add(slider, BorderLayout.CENTER);
}
class ControlPanel extends JPanel {
public ControlPanel(final JSlider slider) {
JCheckBox paintTicks = new JCheckBox("Paint Ticks");
JComboBox minorSpacing = new JComboBox(),
majorSpacing = new JComboBox();

minorSpacing.addItem("0");
minorSpacing.addItem("3");
minorSpacing.addItem("5");
minorSpacing.addItem("10");
minorSpacing.addItem("20");

majorSpacing.addItem("0");
majorSpacing.addItem("3");
majorSpacing.addItem("5");
majorSpacing.addItem("10");
majorSpacing.addItem("20");

add(paintTicks);
add(new JLabel("Minor Tick Spacing:"));
add(minorSpacing);
add(new JLabel("Major Tick Spacing:"));
add(majorSpacing);

paintTicks.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JCheckBox cb = (JCheckBox)e.getSource();
slider.setPaintTicks(cb.isSelected());
slider.repaint();
}
});
minorSpacing.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent e) {
JComboBox cb = (JComboBox)e.getSource();
int spacing = Integer.parseInt(
(String)cb.getSelectedItem());

slider.setMinorTickSpacing(spacing);
slider.revalidate();
}
});
majorSpacing.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent e) {
JComboBox cb = (JComboBox)e.getSource();
int spacing = Integer.parseInt(
(String)cb.getSelectedItem());

slider.setMajorTickSpacing(spacing);
slider.revalidate();
}
});
}
}
}

11.2.3 滑杆标签

 

例11-7 显示缺省的JSlider标签

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Test extends JApplet {
public Test() {
Container contentPane = getContentPane();
JSlider slider = new JSlider();

slider.setPaintLabels(true);
slider.setMajorTickSpacing(20);
contentPane.add(slider, BorderLayout.NORTH);
}
}

例11-8 定制滑杆标签

import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Test extends JApplet {
public Test() {
Container contentPane = getContentPane();
JSlider slider = new JSlider();
Icon[] icons = {
new ImageIcon("basketball.gif"),
new ImageIcon("baseball.gif"),
new ImageIcon("soccer.gif"),
new ImageIcon("clipboard.gif"),
new ImageIcon("filmstrip.gif"),
new ImageIcon("crab.gif"),
};
Hashtable table = new Hashtable();

for(int i=0, loc=0; i < icons.length; i++, loc += 20) {
table.put(new Integer(loc),
new JLabel(Integer.toString(loc),
icons[i],
JLabel.LEFT));
}

slider.setLabelTable(table);
slider.setPaintLabels(true);
slider.setMajorTickSpacing(20);

contentPane.add(slider, BorderLayout.NORTH);
}
}

 

11.2.4 反转滑杆值

 

例11-9 中列出图11-10中示出的小应用程序的代码

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Test extends JApplet {
private JCheckBox checkBox = new JCheckBox("Invert");
private JSlider[] sliders = { new JSlider(),
new JSlider(JSlider.VERTICAL) };

public Test() {
Container contentPane = getContentPane();

contentPane.setLayout(new FlowLayout());
contentPane.add(checkBox);

for(int i=0; i < sliders.length; ++i) {
sliders[i].setPaintLabels(true);
sliders[i].setMajorTickSpacing(20);
contentPane.add(sliders[i]);
}

checkBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
for(int i=0; i < sliders.length; ++i)
sliders[i].setInverted(checkBox.isSelected());
}
});
}
}

11.2.5 滑杆的外延值

 

例11-10 设置一个滑杆的外延值

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class Test extends JApplet {
public Test() {
Container contentPane = getContentPane();
JSlider slider = new JSlider();
JPanel controlPanel = new ControlPanel(slider);

contentPane.add(controlPanel, BorderLayout.NORTH);
contentPane.add(slider, BorderLayout.SOUTH);

slider.addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent e) {
JSlider s = (JSlider)e.getSource();
showStatus("Min: " + s.getMinimum() +
", Max: " + s.getMaximum() +
", Extent: " + s.getExtent() +
", Value: " + s.getValue());
}
});
}
}
class ControlPanel extends JPanel {
public ControlPanel(final JSlider slider) {
JComboBox extent = new JComboBox();

extent.addItem("0");
extent.addItem("10");
extent.addItem("20");
extent.addItem("30");
extent.addItem("40");

add(new JLabel("Extent:"));
add(extent);

extent.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent e) {
JComboBox cb = (JComboBox)e.getSource();
int ext = Integer.parseInt(
(String)cb.getSelectedItem());

slider.setExtent(ext);
slider.revalidate();
}
});
}
}

11.2.6 JSlider属性

 

11.2.7 JSlider事件

 

例11-11 监视一个滑杆的值

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class Test extends JApplet {
public Test() {
Container contentPane = getContentPane();
JSlider slider = new JSlider();

contentPane.add(slider, BorderLayout.NORTH);

slider.addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent e) {
JSlider s = (JSlider)e.getSource();
showStatus("Min: " + s.getMinimum() +
", Max: " + s.getMaximum() +
", Extent: " + s.getExtent() +
", Value: " + s.getValue() +
", Value Is Adjusting: " +
s.getValueIsAdjusting());
}
});
}
}

11.2.8 JSlider类总结

 

11.2.9 AWT兼容

 

11.3 JSeparator

 

例11-12 一个不可见的分隔条

import java.awt.*;
import javax.swing.*;

public class Test extends JApplet {
public void init() {
Container contentPane = getContentPane();
JSeparator s = new JSeparator(JSeparator.VERTICAL);

contentPane.setLayout(new FlowLayout());

contentPane.add(new JButton("left"));
contentPane.add(s);
contentPane.add(new JButton("right"));
}
}

例11-13 控制分隔条的大小

import java.awt.*;
import javax.swing.*;

public class Test extends JApplet {
public void init() {
Container contentPane = getContentPane();
JSeparator s = new JSeparator(JSeparator.VERTICAL);
Dimension ps = s.getPreferredSize();

contentPane.setLayout(new FlowLayout());

contentPane.add(new JButton("left"));
contentPane.add(s);
contentPane.add(new JButton("right"));

s.setPreferredSize(new Dimension(ps.width, 50));
}
}

例11-14 监控分隔条的大小

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();
final JSeparator s =
new JSeparator(JSeparator.VERTICAL);
final Dimension ps = s.getPreferredSize();

contentPane.setLayout(new FlowLayout());

contentPane.add(new JButton("left"));
contentPane.add(s);
contentPane.add(new JButton("right"));

addComponentListener(new ComponentAdapter() {
public void componentShown(ComponentEvent e) {
System.out.println("shown");
adjustSeparatorPreferredSize();
}
public void componentResized(ComponentEvent e) {
System.out.println("resized");
adjustSeparatorPreferredSize();
}
private void adjustSeparatorPreferredSize() {
s.setPreferredSize(new Dimension(ps.width,
getSize().height));
s.revalidate();
}
});
}
}

 

 

11.3.1 分隔条与框

 

例11-15 分隔条与框

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Test extends JApplet {
private JPanel left, rightTop, rightBottom;

private Box box = new Box(BoxLayout.X_AXIS),
rightBox = new Box(BoxLayout.Y_AXIS);

private JSeparator vs, hs; // vs = vertical separator
// hs = horizontal separator
public void init() {
createBoxes();
setPanelBorders();
//setSeparatorPreferredSizes();

left.setPreferredSize(new Dimension(150,0));

getContentPane().add(box, BorderLayout.CENTER);
}
private void createBoxes() {

Component vStrut = box.createVerticalStrut(10),
hStrut = box.createHorizontalStrut(10);

rightBox.add(rightTop = new JPanel());
rightBox.add(box.createVerticalStrut(10));
rightBox.add(hs = new JSeparator());
rightBox.add(box.createVerticalStrut(10));
rightBox.add(rightBottom = new JPanel());

box.add(left = new JPanel());
box.add(box.createHorizontalStrut(10));
box.add(vs = new JSeparator(JSeparator.VERTICAL));
box.add(box.createHorizontalStrut(10));
box.add(rightBox);
}
private void setSeparatorPreferredSizes() {
vs.setMaximumSize(
new Dimension(vs.getPreferredSize().width,
Integer.MAX_VALUE));

hs.setMaximumSize(
new Dimension(Integer.MAX_VALUE,
hs.getPreferredSize().height));
}
private void setPanelBorders() {
left.setBorder(
BorderFactory.createTitledBorder("Left"));
rightTop.setBorder(
BorderFactory.createTitledBorder("Right Top"));
rightBottom.setBorder(
BorderFactory.createTitledBorder("Right Bottom"));
}
}

11.3.2 JSeparator属性

 

11.3.3 JSeparator事件

 

11.3.4 AWT兼容

 

11.4 本章回顾

 

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