达拉草201771010105《面向对象程序设计（java）》第十四周学习总结

  1 package calculator;
  2 
  3 import java.awt.*;
  4 import java.awt.event.*;
  5 import javax.swing.*;
  6 
  7 /**
  8  * A panel with calculator buttons and a result display.
  9  */
 10 public class CalculatorPanel extends JPanel
 11 {
 12    private JButton display;
 13    private JPanel panel;
 14    private double result;
 15    private String lastCommand;
 16    private boolean start;
 17 
 18    public CalculatorPanel()
 19    {
 20       setLayout(new BorderLayout());
 21 
 22       result = 0;
 23       lastCommand = "=";
 24       start = true;
 25 
 26       // add the display
 27 
 28       display = new JButton("0");
 29       display.setEnabled(false);//始能属性不起作用
 30       add(display, BorderLayout.NORTH);
 31 
 32       ActionListener insert = new InsertAction();//数字按钮用insert对象
 33       ActionListener command = new CommandAction();
 34 
 35       // add the buttons in a 4 x 4 grid
 36 
 37       panel = new JPanel();//容器组件
 38       panel.setLayout(new GridLayout(4, 4));//定义容器的布局管理器为4行4列的网格布局管理器
 39 
 40       addButton("7", insert);
 41       addButton("8", insert);
 42       addButton("9", insert);
 43       addButton("/", command);
 44 
 45       addButton("4", insert);
 46       addButton("5", insert);
 47       addButton("6", insert);
 48       addButton("*", command);
 49 
 50       addButton("1", insert);
 51       addButton("2", insert);
 52       addButton("3", insert);
 53       addButton("-", command);
 54 
 55       addButton("0", insert);
 56       addButton(".", insert);
 57       addButton("=", command);
 58       addButton("+", command);
 59 
 60       add(panel, BorderLayout.CENTER);
 61    }
 62 
 63    /**
 64     * Adds a button to the center panel.
 65     * @param label the button label
 66     * @param listener the button listener
 67     */
 68    private void addButton(String label, ActionListener listener)
 69    {
 70       JButton button = new JButton(label);
 71       button.addActionListener(listener);
 72       panel.add(button);
 73    }
 74 
 75    /**
 76     * This action inserts the button action string to the end of the display text.
 77     */
 78    private class InsertAction implements ActionListener
 79    {
 80       public void actionPerformed(ActionEvent event)
 81       {
 82          String input = event.getActionCommand();//command保存发出动作的按钮的标签
 83          if (start)
 84          {
 85             display.setText("");
 86             start = false;
 87          }
 88          display.setText(display.getText() + input);
 89       }
 90    }
 91 
 92    /**
 93     * This action executes the command that the button action string denotes.
 94     */
 95    private class CommandAction implements ActionListener
 96    {
 97       public void actionPerformed(ActionEvent event)
 98       {
 99          String command = event.getActionCommand();
100 
101          if (start)
102          {
103             if (command.equals("-"))
104             {
105                display.setText(command);
106                start = false;
107             }
108             else lastCommand = command;
109          }
110          else
111          {
112             calculate(Double.parseDouble(display.getText()));//calculate调用Double类型数据
113             lastCommand = command;
114             start = true;
115          }
116       }
117    }
118 
119    /**
120     * Carries out the pending calculation.
121     * @param x the value to be accumulated with the prior result.
122     */
123    public void calculate(double x)
124    {
125       if (lastCommand.equals("+")) result += x;
126       else if (lastCommand.equals("-")) result -= x;
127       else if (lastCommand.equals("*")) result *= x;
128       else if (lastCommand.equals("/")) result /= x;
129       else if (lastCommand.equals("=")) result = x;
130       display.setText("" + result);//将result的计算结果更改为数字字符串
131    }
132 }

 1 package calculator;
 2 
 3 import java.awt.*;
 4 import javax.swing.*;
 5 
 6 /**
 7  * @version 1.34 2015-06-12
 8  * @author Cay Horstmann
 9  */
10 public class Calculator
11 {
12    public static void main(String[] args)
13    {
14       EventQueue.invokeLater(() -> {
15          CalculatorFrame frame = new CalculatorFrame();
16          frame.setTitle("Calculator");
17          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
18          frame.setVisible(true);
19       });
20    }
21 }

 1 package calculator;
 2 
 3 import javax.swing.*;
 4 
 5 /**
 6  * A frame with a calculator panel.
 7  */
 8 public class CalculatorFrame extends JFrame
 9 {
10    public CalculatorFrame()
11    {
12       add(new CalculatorPanel());
13       pack();
14    }
15 }

 1 package slider;
 2 
 3 import java.awt.*;
 4 import javax.swing.*;
 5 
 6 /**
 7  * @version 1.15 2015-06-12
 8  * @author Cay Horstmann
 9  */
10 public class SliderTest
11 {
12    public static void main(String[] args)
13    {
14       EventQueue.invokeLater(() -> {
15          SliderFrame frame = new SliderFrame();//生成类对象
16          frame.setTitle("SliderTest");//将此窗体的标题设置为指定的字符串
17          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置用户在此窗体上发起 "close" 时默认执行的操作
18          frame.setVisible(true);//根据参数 b 的值显示或隐藏此 Window
19       });
20    }
21 }

  1 package slider;
  2 
  3 import java.awt.*;
  4 import java.util.*;
  5 import javax.swing.*;
  6 import javax.swing.event.*;
  7 
  8 /**
  9  * A frame with many sliders and a text field to show slider values.
 10  */
 11 public class SliderFrame extends JFrame//类的继承
 12 {
 13    private JPanel sliderPanel;
 14    private JTextField textField;
 15    private ChangeListener listener;
 16 
 17    public SliderFrame()
 18    {
 19       sliderPanel = new JPanel();//生成类对象
 20       sliderPanel.setLayout(new GridBagLayout());//设置此容器的布局管理器为网格包布局管理器。 
 21 
 22       // 为所有 sliders注册监听器
 23       listener = event -> {
 24          //当滑动slider的时候 更新文本域的值
 25          JSlider source = (JSlider) event.getSource();//生成一个让用户以图形方式在有界区间内通过移动滑块来选择值的组件类对象。 
 26          textField.setText("" + source.getValue());//将此 TextComponent 文本设置为指定文本
 27       };
 28 
 29  
 30 
 31       JSlider slider = new JSlider();//创建一个水平滑块。
 32       addSlider(slider, "Plain");
 33 
 34 
 35       slider = new JSlider();
 36       slider.setPaintTicks(true);//在滑块上绘制刻度标记
 37       slider.setMajorTickSpacing(20);//设置主刻度标记的间隔
 38       slider.setMinorTickSpacing(5);
 39       addSlider(slider, "Ticks");
 40 
 41       slider = new JSlider();
 42       slider.setPaintTicks(true);
 43       slider.setSnapToTicks(true);
 44       slider.setMajorTickSpacing(20);
 45       slider.setMinorTickSpacing(5);
 46       addSlider(slider, "Snap to ticks");
 47 
 48       // 添加没有轨迹的平滑快
 49 
 50       slider = new JSlider();
 51       slider.setPaintTicks(true);
 52       slider.setMajorTickSpacing(20);
 53       slider.setMinorTickSpacing(5);
 54       slider.setPaintTrack(false);
 55       addSlider(slider, "No track");
 56 
 57       //添加倒置的平滑快
 58 
 59       slider = new JSlider();
 60       slider.setPaintTicks(true);
 61       slider.setMajorTickSpacing(20);
 62       slider.setMinorTickSpacing(5);
 63       slider.setInverted(true);
 64       addSlider(slider, "Inverted");
 65 
 66       // 添加一个数字标签的平滑快
 67 
 68       slider = new JSlider();
 69       slider.setPaintTicks(true);
 70       slider.setPaintLabels(true);//在滑块上绘制标签。
 71       slider.setMajorTickSpacing(20);
 72       slider.setMinorTickSpacing(5);
 73       addSlider(slider, "Labels");
 74 
 75       // 添加一个字母标签的平滑快
 76 
 77       slider = new JSlider();
 78       slider.setPaintLabels(true);
 79       slider.setPaintTicks(true);//在滑块上绘制刻度标记
 80       slider.setMajorTickSpacing(20);
 81       slider.setMinorTickSpacing(5);
 82 
 83       Dictionary<Integer, Component> labelTable = new Hashtable<>();
 84       labelTable.put(0, new JLabel("A"));//创建 JLabel 实例。
 85       labelTable.put(20, new JLabel("B"));
 86       labelTable.put(40, new JLabel("C"));
 87       labelTable.put(60, new JLabel("D"));
 88       labelTable.put(80, new JLabel("E"));
 89       labelTable.put(100, new JLabel("F"));
 90 
 91       slider.setLabelTable(labelTable);//在给定值处绘制标签
 92       addSlider(slider, "Custom labels");
 93 
 94 
 95       slider = new JSlider();
 96       slider.setPaintTicks(true);
 97       slider.setPaintLabels(true);
 98       slider.setSnapToTicks(true);
 99       slider.setMajorTickSpacing(20);
100       slider.setMinorTickSpacing(20);
101 
102       labelTable = new Hashtable<Integer, Component>();//构造一个新的空哈希表。 
103 
104       // 添加图像
105 
106       labelTable.put(0, new JLabel(new ImageIcon("nine.gif")));
107       labelTable.put(20, new JLabel(new ImageIcon("ten.gif")));
108       labelTable.put(40, new JLabel(new ImageIcon("jack.gif")));
109       labelTable.put(60, new JLabel(new ImageIcon("queen.gif")));
110       labelTable.put(80, new JLabel(new ImageIcon("king.gif")));
111       labelTable.put(100, new JLabel(new ImageIcon("ace.gif")));
112 
113       slider.setLabelTable(labelTable);//用于指定将在给定值处绘制标签
114       addSlider(slider, "Icon labels");
115 
116       // 添加文本域
117 
118       textField = new JTextField();
119       add(sliderPanel, BorderLayout.CENTER);
120       add(textField, BorderLayout.SOUTH);
121       pack();//调整此窗口的大小，以适合其子组件的首选大小和布局。
122    }
123 
124    /**
125     * Adds a slider to the slider panel and hooks up the listener
126     * @param s the slider
127     * @param description the slider description
128     */
129    public void addSlider(JSlider s, String description)//一个让用户以图形方式在有界区间内通过移动滑块来选择值的组件。 
130    {
131       s.addChangeListener(listener);
132       JPanel panel = new JPanel();
133       panel.add(s);
134       panel.add(new JLabel(description));
135       panel.setAlignmentX(Component.LEFT_ALIGNMENT);//设置垂直对齐方式。 
136       GridBagConstraints gbc = new GridBagConstraints();//设置组件间的约束关系
137       gbc.gridy = sliderPanel.getComponentCount();
138       gbc.anchor = GridBagConstraints.WEST;
139       sliderPanel.add(panel, gbc);
140    }
141 }