java实现的计算器功能示例【基于swing组件】

本文实例讲述了java实现的计算器功能。分享给大家供大家参考，具体如下：

package awtdemo;
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;
@suppresswarnings("serial")
public class calculator 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 jbutton keys[] = new jbutton[keys.length];
    private jbutton commands[] = new jbutton[command.length];
    private jtextfield resulttext = new jtextfield("0");
    private boolean firstdigit = true;
    private double resultnum = 0.0;
    private string operator = "=";
    private boolean operatevalidflag = true;
    public calculator() {
        init();
        this.setbackground(color.light_gray);
        this.settitle("www.jb51.net - 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 panel1 = new jpanel();
        panel1.setlayout(new borderlayout(3, 3));
        panel1.add("north", commandspanel);
        panel1.add("west", 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);
        for (int i = 0; i < keys.length; i++) {
            keys[i].addactionlistener(this);
        }
        for (int i = 0; i < command.length; i++) {
            commands[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);
            }
        }
    }
    private void handlenumber(string key) {
        if (firstdigit) {
            resulttext.settext(key);
        } else if ((key.equals(".")) && (resulttext.gettext().indexof(".") < 0)) {
            resulttext.settext(resulttext.gettext() + ".");
        } else if (!key.equals(".")) {
            resulttext.settext(resulttext.gettext() + key);
        }
        firstdigit = false;
    }
    private void handlec() {
        resulttext.settext("0");
        firstdigit = true;
        operator = "=";
    }
    private void handleoperator(string key) {
        if (operator.equals("/")) {
            if (getnumberfromtext() == 0.0) {
                operatevalidflag = false;
                resulttext.settext("除数不能为零");
            } else {
                resultnum /= getnumberfromtext();
            }
        } else if (operator.equals("1/x")) {
            if (resultnum == 0.0) {
                operatevalidflag = false;
                resulttext.settext("零没有倒数");
            } else {
                resultnum = 1 / resultnum;
            }
        } else if (operator.equals("+")) {
            resultnum += getnumberfromtext();
        } else if (operator.equals("-")) {
            resultnum -= getnumberfromtext();
        } else if (operator.equals("*")) {
            resultnum *= getnumberfromtext();
        } else if (operator.equals("sqrt")) {
            resultnum = math.sqrt(resultnum);
        } else if (operator.equals("%")) {
            resultnum = resultnum / 100;
        } else if (operator.equals("+/-")) {
            resultnum = resultnum * (-1);
        } else if (operator.equals("=")) {
            resultnum = getnumberfromtext();
        }
        if (operatevalidflag) {
            long t1;
            double t2;
            t1 = (long) resultnum;
            t2 = resultnum - t1;
            if (t2 == 0) {
                resulttext.settext(string.valueof(t1));
            } else {
                resulttext.settext(string.valueof(resultnum));
            }
        }
        operator = key;
        firstdigit = true;
        operatevalidflag = true;
    }
    private double getnumberfromtext() {
        double result = 0;
        try {
            result = double.valueof(resulttext.gettext()).doublevalue();
        } catch (numberformatexception e) {
        }
        return result;
    }
    public static void main(string args[]) {
        calculator calculator1 = new calculator();
        calculator1.setvisible(true);
        calculator1.setdefaultcloseoperation(jframe.exit_on_close);
    }
}

运行效果：

ps：这里再为大家推荐几款计算工具供大家进一步参考借鉴：

在线一元函数（方程）求解计算工具：

科学计算器在线使用_高级计算器在线计算：

在线计算器_标准计算器：

更多关于java算法相关内容感兴趣的读者可查看本站专题：《java数据结构与算法教程》、《java操作dom节点技巧总结》、《java文件与目录操作技巧汇总》和《java缓存操作技巧汇总》

希望本文所述对大家java程序设计有所帮助。