第十二周
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布局管理器
绝对界面
package 计算机界面; import java.awt.*; import javax.swing.*; public class DD extends JFrame{ JButton jb1,jb2; JTextField jtf; JPasswordField jpwd; JLabel jl1,jl2; JPanel jp1,jp2,jp3; public static void main(String[] args) { // TODO Auto-generated method stub DD test6=new DD(); } public DD() { //创建组件 jb1=new JButton("确认"); jb2=new JButton("取消"); jtf=new JTextField(10); jpwd=new JPasswordField(10); jl1=new JLabel("用户名:"); jl2=new JLabel("密 码:"); jp1=new JPanel(); jp2=new JPanel(); jp3=new JPanel(); //设置布局管理器 this.setLayout(new GridLayout(3,1,5,5)); //添加组件 jp1.add(jl1); jp1.add(jtf); jp2.add(jl2); jp2.add(jpwd); jp3.add(jb1); jp3.add(jb2); this.add(jp1); this.add(jp2); this.add(jp3); //设置窗体属性 this.setTitle("登录界面"); this.setSize(280, 160); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.setVisible(true); } }
运行结果
计算器界面
代码源
package 计算机界面; import java.awt.BorderLayout; import java.awt.Color; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTextField; public class jj extends JFrame implements ActionListener { private final String[] KEYS = { "7", "8", "9", "/", "sqrt", "4", "5", "6", "*", "%", "1", "2", "3", "-", "1/x", "0", "+/-", ".", "+", "=" }; private final String[] COMMAND = { "Backspace", "CE", "C" }; private final String[] M = { " ", "MC", "MR", "MS", "M+" }; private JButton keys[] = new JButton[KEYS.length]; private JButton commands[] = new JButton[COMMAND.length]; private JButton m[] = new JButton[M.length]; private JTextField resultText = new JTextField("0"); private boolean firstDigit = true; private double resultNum = 0.0; private String operator = "="; private boolean operateValidFlag = true; public jj() { super(); init(); this.setBackground(Color.LIGHT_GRAY); this.setTitle("计算器"); this.setLocation(500, 300); this.setResizable(false); this.pack(); } private void init() { resultText.setHorizontalAlignment(JTextField.RIGHT); resultText.setEditable(false); resultText.setBackground(Color.WHITE); JPanel calckeysPanel = new JPanel(); calckeysPanel.setLayout(new GridLayout(4, 5, 3, 3)); for (int i = 0; i < KEYS.length; i++) { keys[i] = new JButton(KEYS[i]); calckeysPanel.add(keys[i]); keys[i].setForeground(Color.blue); } keys[3].setForeground(Color.red); keys[8].setForeground(Color.red); keys[13].setForeground(Color.red); keys[18].setForeground(Color.red); keys[19].setForeground(Color.red); JPanel commandsPanel = new JPanel(); commandsPanel.setLayout(new GridLayout(1, 3, 3, 3)); for (int i = 0; i < COMMAND.length; i++) { commands[i] = new JButton(COMMAND[i]); commandsPanel.add(commands[i]); commands[i].setForeground(Color.red); } JPanel calmsPanel = new JPanel(); calmsPanel.setLayout(new GridLayout(5, 1, 3, 3)); for (int i = 0; i < M.length; i++) { m[i] = new JButton(M[i]); calmsPanel.add(m[i]); m[i].setForeground(Color.red); } JPanel panel1 = new JPanel(); panel1.setLayout(new BorderLayout(3, 3)); panel1.add("North", commandsPanel); panel1.add("Center", calckeysPanel); JPanel top = new JPanel(); top.setLayout(new BorderLayout()); top.add("Center", resultText); getContentPane().setLayout(new BorderLayout(3, 5)); getContentPane().add("North", top); getContentPane().add("Center", panel1); getContentPane().add("West", calmsPanel); for (int i = 0; i < KEYS.length; i++) { keys[i].addActionListener(this); } for (int i = 0; i < COMMAND.length; i++) { commands[i].addActionListener(this); } for (int i = 0; i < M.length; i++) { m[i].addActionListener(this); } } public void actionPerformed(ActionEvent e) { String label = e.getActionCommand(); if (label.equals(COMMAND[0])) { handleBackspace(); } else if (label.equals(COMMAND[1])) { resultText.setText("0"); } else if (label.equals(COMMAND[2])) { handleC(); } else if ("0123456789.".indexOf(label) >= 0) { handleNumber(label); } else { handleOperator(label); } } private void handleBackspace() { String text = resultText.getText(); int i = text.length(); if (i > 0) { text = text.substring(0, i - 1); if (text.length() == 0) { resultText.setText("0"); firstDigit = true; operator = "="; } else { resultText.setText(text); } } } /** * 处理数字键被按下的事件 * * @param key */ private void handleNumber(String key) { if (firstDigit) { // 输入的第一个数字 resultText.setText(key); } else if ((key.equals(".")) && (resultText.getText().indexOf(".") < 0)) { // 输入的是小数点,并且之前没有小数点,则将小数点附在结果文本框的后面 resultText.setText(resultText.getText() + "."); } else if (!key.equals(".")) { // 如果输入的不是小数点,则将数字附在结果文本框的后面 resultText.setText(resultText.getText() + key); } // 以后输入的肯定不是第一个数字了 firstDigit = false; } /** * 处理C键被按下的事件 */ private void handleC() { // 初始化计算器的各种值 resultText.setText("0"); firstDigit = true; operator = "="; } /** * 处理运算符键被按下的事件 * * @param key */ private void handleOperator(String key) { if (operator.equals("/")) { // 除法运算 // 如果当前结果文本框中的值等于0 if (getNumberFromText() == 0.0) { // 操作不合法 operateValidFlag = false; resultText.setText("除数不能为零"); } else { resultNum /= getNumberFromText(); } } else if (operator.equals("1/x")) { // 倒数运算 if (resultNum == 0.0) { // 操作不合法 operateValidFlag = false; resultText.setText("零没有倒数"); } else { resultNum = 1 / resultNum; } } else if (operator.equals("+")) { // 加法运算 resultNum += getNumberFromText(); } else if (operator.equals("-")) { // 减法运算 resultNum -= getNumberFromText(); } else if (operator.equals("*")) { // 乘法运算 resultNum *= getNumberFromText(); } else if (operator.equals("sqrt")) { // 平方根运算 resultNum = Math.sqrt(resultNum); } else if (operator.equals("%")) { // 百分号运算,除以100 resultNum = resultNum / 100; } else if (operator.equals("+/-")) { // 正数负数运算 resultNum = resultNum * (-1); } else if (operator.equals("=")) { // 赋值运算 resultNum = getNumberFromText(); } if (operateValidFlag) { // 双精度浮点数的运算 long t1; double t2; t1 = (long) resultNum; t2 = resultNum - t1; if (t2 == 0) { resultText.setText(String.valueOf(t1)); } else { resultText.setText(String.valueOf(resultNum)); } } // 运算符等于用户按的按钮 operator = key; firstDigit = true; operateValidFlag = true; } /** * 从结果文本框中获取数字 * * @return */ private double getNumberFromText() { double result = 0; try { result = Double.valueOf(resultText.getText()).doubleValue(); } catch (NumberFormatException e) { } return result; } public static void main(String args[]) { jj calculator1 = new jj(); calculator1.setVisible(true); calculator1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } }
运行结果
学习总结
1.让我知道如何布局管理。
2.有了一个大概的布局思维。
3.对java的了解又了一个新的思维思想
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