製作一個類似windows上的簡易小算盤，功能只需 “+”、“-”、”C”、“=”，以及數字鍵即可
其運算只需做整數運算即可，但必須跟windows小算盤一樣可以連續運算:
例如1+2+3-4+5-3最後才按”=”，中途按下的”+”、”-”都必須馬上呈現當下的答案
計算機按鈕排列方式請參考下圖
請務必做出避免溢位的error功能，意思為運算式不能超過999999999，
否則顯示error，而error之前的運算則全部清除，一切歸零(如同按下”C”鍵)
(若參考網路上的小算盤，請務必在最上方註明!! 若無註明而被抓到者一律零分)
(如果介面越接近windows上的小算盤則給予加分，例如一些小細節: 背景漸層、圓角按鈕等等)
這是我做的 Demo 範例。
主要有幾個比較困難的部分，win7 計算機滑鼠移動到按鈕上時，會有逐漸變亮的趨勢。
這一點用自動刷新去克服，即本身就會刷新，因此不用特別去顧慮它。多一個全區變數去處理就好。
漸層按鈕怎麼做？在 paintComponent() 中去繪製。使用 LinearGradientPaint，
方法是設兩點，代表在這兩點之間產生線性的方程，然後設置顏色與分配比例(0~1)。
GridBagLayout 就參考網路上的介紹囉
http://pydoing.blogspot.tw/2011/05/java-gridbaglayout.html
| gridx | 行數 |
| gridy | 列數 |
| gridwidth | 行寬 |
| gridheight | 列高 |
| weightx | 行權值 |
| weighty | 列權值 |
| fill | 填滿方式 |
| anchor | 定位點 |
填滿方式有底下數種
| GridBagConstraints.BOTH | 垂直水平都填滿 |
| GridBagConstraints.VERTICAL | 垂直填滿 |
| GridBagConstraints.HORIZONTAL | 水平填滿 |
| GridBagConstraints.NONE | 不填滿 |
定位點也有底下數種
| GridBagConstraints.CENTER | 中央對齊 |
| GridBagConstraints.EAST | 向右對齊 |
| GridBagConstraints.SOUTHEAST | 右下對齊 |
| GridBagConstraints.SOUTH | 向下對齊 |
| GridBagConstraints.SOUTHWEST | 左下對齊 |
| GridBagConstraints.WEST | 向左對齊 |
| GridBagConstraints.NORTHWEST | 左上對齊 |
| GridBagConstraints.NORTH | 向上對齊 |
| GridBagConstraints.NORTHEAST | 右上對齊 |
package ce1002.A7.s100502205;
import java.util.Stack;
import java.util.StringTokenizer;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.Insets;
import java.awt.Font;
import java.awt.geom.Point2D;
import java.awt.LinearGradientPaint;
import java.awt.RadialGradientPaint;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
import java.awt.GraphicsEnvironment;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.KeyEventDispatcher;
import java.awt.KeyboardFocusManager;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.border.Border;
public class A7 extends JFrame implements KeyEventDispatcher {
ColoredPanel background;
RoundedButton monitor;
RoundedButton monitorE;
String monitorStr = "0";
String monitorExp = "";
ButtonListener blistener;
Font font = new Font("Consolas", Font.PLAIN, 50);
int operator = 0;// add 0, substract 1
long calcBuffer = 0;
boolean errorFlag = false;
boolean Cpress = true;
int leftParenthese = 0, rightParenthese = 0; // '('
public A7() {
this.setTitle("小算盤");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(450, 500);
this.setResizable(false);
background = new ColoredPanel();
background.setLayout(new GridBagLayout());
this.add(background);
blistener = new ButtonListener();
monitor = new RoundedButton(5, String.format("%10s.", monitorStr), this);
monitor.setFont(font);
monitor.setEnabled(false);
GridBagConstraints GBC = new GridBagConstraints();
GBC.gridx = 0;
GBC.gridy = 0;
GBC.gridwidth = 5;
GBC.gridheight = 1;
GBC.ipadx = 10;
GBC.ipady = 0;
GBC.weightx = 0;
GBC.weighty = 0;
GBC.insets = new Insets(10, 10, 10, 10);
GBC.fill = GridBagConstraints.HORIZONTAL;
GBC.anchor = GridBagConstraints.EAST;
background.add(monitor, GBC);
// <Extended>
monitorE = new RoundedButton(5, String.format("%35s", monitorExp), this);
monitorE.setFont(new Font("Consolas", Font.PLAIN, 20));
monitorE.setEnabled(false);
GBC = new GridBagConstraints();
GBC.gridx = 0;
GBC.gridy = 5;
GBC.gridwidth = 5;
GBC.gridheight = 1;
GBC.ipadx = 10;
GBC.ipady = 0;
GBC.weightx = 0;
GBC.weighty = 0;
GBC.insets = new Insets(10, 10, 10, 10);
GBC.fill = GridBagConstraints.NONE;
GBC.anchor = GridBagConstraints.EAST;
background.add(monitorE, GBC);
// </Extended>
String[] str = { "7", "8", "9", "-", "4", "5", "6", "+", "1", "2", "3",
"=", "0", "C", "*", "/", "(", ")" };
int[] px = { 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 2, 4, 4, 4, 4 };
int[] py = { 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 1, 2, 3, 4 };
int[] gw = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1 };
int[] gh = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1 };
for (int i = 0; i < 18; i++) {
GBC = new GridBagConstraints();
GBC.gridx = px[i];
GBC.gridy = py[i];
GBC.gridwidth = gw[i];
GBC.gridheight = gh[i];
GBC.ipadx = (gw[i] - 1) * 85 + 40;
GBC.ipady = (gh[i] - 1) * 60;
GBC.weightx = 0;
GBC.weighty = 0;
GBC.insets = new Insets(10, 10, 10, 10);
GBC.fill = GridBagConstraints.NONE;
GBC.anchor = GridBagConstraints.CENTER;
RoundedButton rb = new RoundedButton(5, str[i], this);
rb.setActionCommand(str[i]);
rb.addActionListener(blistener);
rb.addMouseMotionListener(new MMListener(rb));
background.add(rb, GBC);
}
this.setVisible(true);
KeyboardFocusManager.getCurrentKeyboardFocusManager()
.addKeyEventDispatcher(this);
}
public boolean dispatchKeyEvent(KeyEvent e) {
if (e.getID() == KeyEvent.KEY_RELEASED)
return false;
if (e.getKeyChar() == '(') {
if (e.getExtendedKeyCode() != 0)
processCalculator("(");
} else if (e.getKeyChar() == ')') {
if (e.getExtendedKeyCode() != 0)
processCalculator(")");
} else if (KeyEvent.VK_0 <= e.getKeyCode()
&& e.getKeyCode() <= KeyEvent.VK_9) {
processCalculator("" + (char) e.getKeyCode()); // ASCII
} else if (e.getKeyChar() == '+') {
processCalculator("+");
} else if (e.getKeyChar() == '-') {
processCalculator("-");
} else if (e.getKeyChar() == '*') {
processCalculator("*");
} else if (e.getKeyChar() == '/') {
processCalculator("/");
} else if (e.getKeyCode() == KeyEvent.VK_ENTER) {
processCalculator("=");
} else if (e.getKeyCode() == KeyEvent.VK_ESCAPE) {
processCalculator("C");
} else {// right number panel
if ('0' <= e.getKeyChar() && e.getKeyChar() <= '9'
&& e.getExtendedKeyCode() != 0) {
processCalculator("" + e.getKeyChar());
return false;
}
// System.out.println(e.getExtendedKeyCode());
}
return false;
}
class MMListener implements MouseMotionListener {
private RoundedButton btn;
public MMListener(RoundedButton btn) {
this.btn = btn;
}
public void mouseDragged(MouseEvent e) {
}
public void mouseMoved(MouseEvent e) {
btn.touchTimes += 30;
if (btn.touchTimes > 100)
btn.touchTimes = 100;
background.repaint();
try {
Thread.sleep(30);
} catch (Exception ee) {
}
}
}
public void processExp(String cmd) {
if (cmd.equals("C")) {
leftParenthese = 0;
rightParenthese = 0;
monitorExp = "";
Cpress = true;
monitorE.setText(String.format("%35s", monitorExp));
return;
}
if (cmd.equals("=")) {
if (monitorStr.trim().length() != 0)
monitorExp += monitorStr.trim();
calcBuffer = calcInfix(monitorExp);
leftParenthese = 0;
rightParenthese = 0;
monitorExp = "";
monitorE.setText(String.format("%35s", monitorExp));
// infix to prefix, and calculate result.
return;
}
boolean hasPrint = false;
if (isOperator(cmd.charAt(0)) && Cpress == false) {
if (monitorExp.trim().length() == 0
&& monitorStr.trim().length() == 0) {
monitorExp = "" + calcBuffer;
hasPrint = true;
}
}
if (isOperator(cmd.charAt(0))) {
if (!monitorStr.equals("") && !hasPrint)
monitorExp = monitorExp + monitorStr;
}
if (cmd.charAt(0) == ')') {
if (!monitorStr.equals("") && !hasPrint)
monitorExp = monitorExp + monitorStr;
}
monitorE.setText(String.format("%35s", monitorExp));
}
boolean isOperator(char c) {
switch (c) {
case '+':
case '-':
case '*':
case '/':
return true;
}
return false;
}
int operatorPriority(char c) {
switch (c) {
case '(':
return 1;
case '+':
return 2;
case '-':
return 2;
case '*':
return 3;
case '/':
return 3;
}
return -1; // error state
}
public int calcPostfix(String postfix) {
Stack<Integer> stk = new Stack<Integer>();
StringTokenizer st = new StringTokenizer(postfix, " ");
String token;
try {
while (st.hasMoreTokens()) {
token = st.nextToken();
switch (token.charAt(0)) {
case '+':
case '-':
case '*':
case '/':
if (stk.size() >= 2) {
int a, b;
b = stk.pop();
a = stk.pop();
if (token.equals("+"))
stk.push(a + b);
if (token.equals("-"))
stk.push(a - b);
if (token.equals("*"))
stk.push(a * b);
if (token.equals("/"))
stk.push(a / b);
}
break;
case '(':
case ')':
break;
default:
stk.push(Integer.parseInt(token));
}
}
} catch (Exception e) {
monitorStr = "Error";
monitor.setText(String.format("%10s.", monitorStr));
calcBuffer = 0;
errorFlag = true;
operator = -1;
}
if (stk.isEmpty())
return 0;
return stk.pop();
}
public int calcInfix(String infix) {
String postfix = "";
int i, len = infix.length();
Stack<Character> opStk = new Stack<Character>();
for (i = 0; i < len; i++) {
if (Character.isDigit(infix.charAt(i))) {
while (i < len && Character.isDigit(infix.charAt(i))) {
postfix += infix.charAt(i);
i++;
}
i--;
postfix += ' ';
} else {
if (infix.charAt(i) == ')') {
while (!opStk.isEmpty() && opStk.peek() != '(') {
postfix += opStk.pop();
postfix += ' ';
}
if (!opStk.isEmpty())
opStk.pop();
} else {
while (!opStk.isEmpty() && infix.charAt(i) != '(') {
if (opStk.peek() != '(') {
if (operatorPriority(opStk.peek()) >= operatorPriority(infix
.charAt(i))) {
postfix += opStk.pop();
postfix += ' ';
} else
break;
} else
break;
}
opStk.push(infix.charAt(i));
}
}
}
while (!opStk.empty()) {
postfix += opStk.pop();
postfix += ' ';
}
System.out.println("in : " + infix + ", post : " + postfix);
return calcPostfix(postfix);
}
public void processCalculator(String cmd) {
// System.out.println(cmd);
if (errorFlag == true) {
monitorStr = "";
monitorExp = "";
Cpress = true;
errorFlag = false;
monitorE.setText(String.format("%35s", monitorExp));
}
if (cmd.matches("[0-9]")) {
Cpress = false;
if (monitorStr.length() < 10) {
if (monitorStr.compareTo("0") == 0)
monitorStr = "";
monitorStr = monitorStr + cmd;
monitor.setText(String.format("%10s.", monitorStr));
}
return;
}
processExp(cmd);// <here push number and operator>
if (cmd.equals("C")) {
monitorStr = "0";
Cpress = true;
monitor.setText(String.format("%10s.", monitorStr));
operator = 0;
calcBuffer = 0;
return;
}
Cpress = false;
if (cmd.equals("=")) {
try {
// calculate in processExp()
monitorStr = "" + calcBuffer;
if (monitorStr.length() >= 10)
throw new Exception("OVERFLOW");
} catch (Exception ee) {// parseInt Error
monitorStr = "Error";
monitor.setText(String.format("%10s.", monitorStr));
calcBuffer = 0;
errorFlag = true;
operator = -1;
return;
}
if(errorFlag) return;
monitor.setText(String.format("%10s.", monitorStr));
monitorStr = "";
return;
}
try {
System.out.println(monitorExp);
if (operator == 0) {// add
calcBuffer += Integer.parseInt(monitorStr);
monitorStr = "" + calcBuffer;
}
if (operator == 1) {// substract
calcBuffer -= Integer.parseInt(monitorStr);
monitorStr = "" + calcBuffer;
}
if (operator == 2) {// multiply
calcBuffer = calcInfix(monitorExp);
monitorStr = "" + calcBuffer;
calcBuffer = 0;
}
if (operator == 3) {// divide
calcBuffer = calcInfix(monitorExp);
monitorStr = "" + calcBuffer;
calcBuffer = 0;
}
System.out.println(calcInfix(monitorExp));
if (monitorStr.length() >= 10)
throw new Exception("OVERFLOW");
monitor.setText(String.format("%10s.", monitorStr));
} catch (Exception ee) {// parseInt Error
if (ee.getMessage().equals("OVERFLOW")) {
monitorStr = "Error";
monitor.setText(String.format("%10s.", monitorStr));
calcBuffer = 0;
errorFlag = true;
operator = -1;
return;
}
}
monitorStr = "";
if (isOperator(cmd.charAt(0))) {
if (monitorExp.length() > 0
&& isOperator(monitorExp.charAt(monitorExp.length() - 1)))
monitorExp = monitorExp.substring(0, monitorExp.length() - 1);
if (monitorExp.length() > 0
&& monitorExp.charAt(monitorExp.length() - 1) == '(')
monitorExp += '0';
monitorExp += cmd;
monitorE.setText(String.format("%35s", monitorExp));
}
if (cmd.charAt(0) == '(') {
if (monitorExp.length() > 0
&& monitorExp.charAt(monitorExp.length() - 1) == ')') {
monitorExp = "";
monitorStr = "";
}
leftParenthese++;
operator = 0;
monitorExp += '(';
monitorE.setText(String.format("%35s", monitorExp));
}
if (cmd.charAt(0) == ')' && rightParenthese < leftParenthese) {
if (monitorExp.length() > 0
&& monitorExp.charAt(monitorExp.length() - 1) == '(')
monitorExp += "0";
rightParenthese++;
operator = 0;
monitorExp += ')';
monitorE.setText(String.format("%35s", monitorExp));
}
if (cmd.equals("+"))
operator = 0;
if (cmd.equals("-"))
operator = 1;
if (cmd.equals("*"))
operator = 2;
if (cmd.equals("/"))
operator = 3;
}
class ButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
String cmd = e.getActionCommand();
processCalculator(cmd);
}
}
public static void main(String[] args) {
new A7();
}
}
class ColoredPanel extends JPanel {
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Color background = new Color(217, 228, 241);
g.setColor(background);
g.fillRect(0, 0, getWidth(), getHeight());
}
}
class RoundedButton extends JButton {
private int ah;
private JFrame frame;
public int touchTimes;// 0-10
class RoundedBorder implements Border {
public Insets getBorderInsets(Component c) {
return new Insets(ah, ah, ah, ah);
}
public boolean isBorderOpaque() {
return true;
}
public void paintBorder(Component c, Graphics g, int x, int y,
int width, int height) {
Color cc = new Color(240, 249 - (int) (touchTimes * 0.5),
253 - (int) (touchTimes * 1.4));
g.setColor(cc);
g.drawRoundRect(x, y, width - 1, height - 1, ah, ah);
}
}
RoundedButton(int ah, String str, JFrame frame) {
super(str);
this.ah = ah;
this.frame = frame;
this.touchTimes = 0;
this.setBorder(new RoundedBorder());
this.setFont(new Font("Consolas", Font.BOLD, 28));
this.setOpaque(false);
this.setContentAreaFilled(false);
/*
* GraphicsEnvironment e = GraphicsEnvironment
* .getLocalGraphicsEnvironment(); String[] fontnames =
* e.getAvailableFontFamilyNames(); for (int i = 0; i <
* fontnames.length; i++) System.out.println(fontnames[i]);
*/
}
@Override
protected void paintComponent(Graphics g) {
Point2D start = new Point2D.Float(this.getWidth(), 0);
Point2D end = new Point2D.Float(this.getWidth(), this.getHeight());
float[] dist = { 0.0f, 0.40f, 0.45f, 1.0f };
Color c1, c2, c3;
c1 = new Color(247, 251 - (int) (touchTimes * 0.2),
255 - (int) (touchTimes * 0.2));
// c1 = new Color(255, 238, 220);
c2 = new Color(240, 249 - (int) (touchTimes * 0.5),
253 - (int) (touchTimes * 1.4));
// c2 = new Color(255, 207, 106);
c3 = new Color(255, 255, 245);
Color[] colors = { c1, c1, c2, c3 };
LinearGradientPaint p = new LinearGradientPaint(start, end, dist,
colors);
Graphics2D g2d = (Graphics2D) g;
g2d.setPaint(p);
g2d.fillRoundRect(0, 0, getWidth(), getHeight(), ah, ah);
touchTimes -= 12;
if (touchTimes < 0)
touchTimes = 0;
/*
* Point2D center = new Point2D.Float(getWidth() / 2, getHeight() / 2);
* float radius = 25; float[] dist = { 0.0f, 1.0f }; Color c1, c2; c1 =
* new Color(233, 212, 173); c2 = new Color(232, 238, 246); Color[]
* colors = { c1, c2 }; RadialGradientPaint p = new
* RadialGradientPaint(center, radius, dist, colors); Graphics2D g2d =
* (Graphics2D) g; g2d.setPaint(p); g2d.fillRoundRect(0, 0, getWidth(),
* getHeight(), ah, ah);
*/
super.paintComponent(g);
}
}
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