如何在AWT中find一个button来源（计算器作业）

我们被要求做一个简单的GUI计算器，我用getSource（）来检测button，因为这是他们教给我们的。 它通过键入第一个和第二个值，然后select操作，它的工作。 但我犯了一个错误，因为他们希望我们做的是数字也应该是button，就像一个真正的计算器。 所以我怎么得到每个button使用getSource（）的价值？ 就像当我按下button1和2等于3.inheritance人什么都做了

import java.awt.*; import java.awt.event.*; public class SimpleCalculator implements ActionListener { // containers private Frame f; private Panel p1, p2, p3, p4; // components private Label l1, l2, l3; private TextField tf1, tf2, tf3; private Button bAdd, bSub, bMul, bDiv, bClear; public SimpleCalculator() { f = new Frame("My First GUI App"); p1 = new Panel(); p2 = new Panel(); p3 = new Panel(); p4 = new Panel(); l1 = new Label("First: "); l2 = new Label("Second: "); l3 = new Label("Result: "); tf1 = new TextField(15); tf2 = new TextField(15); tf3 = new TextField(15); bAdd = new Button("+"); bSub = new Button("-"); bMul = new Button("*"); bDiv = new Button("/"); bClear = new Button("C"); } public void launchFrame() { // use default layout manager of the Panel (FlowLayout) p1.add(l1); p1.add(tf1); p2.add(l2); p2.add(tf2); p3.add(l3); p3.add(tf3); p4.add(bAdd); p4.add(bSub); p4.add(bMul); p4.add(bDiv); p4.add(bClear); // change the layout manager of the Frame, // use GridLayout(4, 1) f.setLayout(new GridLayout(4, 1)); f.add(p1); f.add(p2); f.add(p3); f.add(p4); f.pack(); f.setVisible(true); // register event handlers bAdd.addActionListener(this); bSub.addActionListener(this); bMul.addActionListener(this); bDiv.addActionListener(this); bClear.addActionListener(this); f.addWindowListener(new MyCloseButtonHandler()); } // override the actionPerformed method public void actionPerformed(ActionEvent ae) { Object source = ae.getSource(); double num1, num2, result = 0.0; if (tf1.getText() != null && tf2.getText() != null) { num1 = Double.parseDouble(tf1.getText()); num2 = Double.parseDouble(tf2.getText()); if (source == bAdd) result = num1 + num2; else if (source == bSub) result = num1 - num2; else if (source == bMul) result = num1 * num2; else if (source == bDiv) result = num1 / num2; else if (source == bClear) { tf1.setText("0.0"); tf2.setText("0.0"); tf3.setText("0.0"); } else {} // tf3.setText(new Double(result).toString()); tf3.setText("" + result); } } private class MyCloseButtonHandler extends WindowAdapter { public void windowClosing(WindowEvent we) { System.exit(0); } } public static void main(String args[]) { SimpleCalculator sc = new SimpleCalculator(); sc.launchFrame(); } } 

Answer 1

我倾向于每个button的数字，以及操作数的每个button，添加文本到“input/输出”的文本字段。

还有一个button= 。 当=button被激活时，调用javax.script.ScriptEngine来计算I / O文本字段的内容，并将结果写回到它。

例如

=

 import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.border.EmptyBorder; import java.util.ArrayList; // script package introduced in Java 1.6 import javax.script.ScriptEngineManager; import javax.script.ScriptEngine; import javax.script.ScriptException; class ScriptEngineCalculator implements ActionListener, KeyListener { private JTextField io; private ScriptEngine engine; private ArrayList<JButton> controls; private JPanel ui; ScriptEngineCalculator() { initUI(); } public final void initUI() { // obtain a reference to the JS engine engine = new ScriptEngineManager(). getEngineByExtension("js"); ui = new JPanel(new BorderLayout(2, 2)); controls = new ArrayList<JButton>(); JPanel text = new JPanel(new GridLayout(0, 1, 3, 3)); ui.add(text, BorderLayout.PAGE_START); io = new JTextField(15); Font font = io.getFont(); font = font.deriveFont(font.getSize() * 1.8f); io.setFont(font); io.setHorizontalAlignment(SwingConstants.TRAILING); io.setFocusable(false); text.add(io); JPanel buttons = new JPanel(new GridLayout(4, 4, 2, 2)); ui.add(buttons, BorderLayout.CENTER); String[] keyValues = { "7", "8", "9", "/", "4", "5", "6", "*", "1", "2", "3", "-", "0", ".", "C", "+" }; for (String keyValue : keyValues) { addButton(buttons, keyValue); } JButton equals = new JButton("="); configureButton(equals); ui.add(equals, BorderLayout.LINE_END); ui.setBorder(new EmptyBorder(5, 5, 5, 5)); } public JComponent getUI() { return ui; } public void addButton(Container c, String text) { JButton b = new JButton(text); configureButton(b); c.add(b); } public void configureButton(JButton b) { Font f = b.getFont(); b.setFont(f.deriveFont(f.getSize() * 1.5f)); b.addActionListener(this); b.addKeyListener(this); controls.add(b); } public void calculateResult() { try { Object result = engine.eval(io.getText()); if (result == null) { io.setText("Output was 'null'"); } else { io.setText(result.toString()); } } catch (ScriptException se) { io.setText(se.getMessage()); } } @Override public void actionPerformed(ActionEvent ae) { String command = ae.getActionCommand(); if (command.equals("C")) { io.setText(""); } else if (command.equals("=")) { calculateResult(); } else { io.setText(io.getText() + command); } } private JButton getButton(String text) { for (JButton button : controls) { String s = button.getText(); if (text.endsWith(s) || (s.equals("=") && (text.equals("Equals") || text.equals("Enter")))) { return button; } } return null; } /* START - Because I hate mice. */ @Override public void keyPressed(KeyEvent ke) { } @Override public void keyReleased(KeyEvent ke) { String s = KeyEvent.getKeyText(ke.getKeyCode()); JButton b = getButton(s); if (b != null) { b.requestFocusInWindow(); b.doClick(); } } @Override public void keyTyped(KeyEvent ke) { } /* END - Because I hate mice. */ public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { ScriptEngineCalculator sc = new ScriptEngineCalculator(); JFrame f = new JFrame("Calculet"); f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); f.setContentPane(sc.getUI()); f.pack(); f.setMinimumSize(f.getSize()); f.setLocationByPlatform(true); f.setVisible(true); } }); } } 

Answer 2

你可以检查你的源代码是否是一个Button（实际上并不需要，因为你应该知道它只是从一个button中调用），然后input一个button并使用.getText（）

 String sourceText; if (ae.getSource() instanceof Button) { sourceText = ((Button)ae.getSource()).getText(); }