温馨提示×

温馨提示×

您好,登录后才能下订单哦!

密码登录×
登录注册×
其他方式登录
点击 登录注册 即表示同意《亿速云用户服务条款》

Android如何实现计算器功能

发布时间:2022-08-12 11:15:50 来源:亿速云 阅读:251 作者:iii 栏目:开发技术

今天小编给大家分享一下Android如何实现计算器功能的相关知识点,内容详细,逻辑清晰,相信大部分人都还太了解这方面的知识,所以分享这篇文章给大家参考一下,希望大家阅读完这篇文章后有所收获,下面我们一起来了解一下吧。

一、UI布局及代码

  • 页面效果

Android如何实现计算器功能

  • 布局代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="8">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:id="@+id/text_view"
        android:layout_weight="2"
        android:textSize="70dp"
        android:gravity="right|bottom"
        android:maxLines="2" />


    <TextView
        android:id="@+id/result_view"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:gravity="right|bottom"
        android:maxLines="1"
        android:textSize="65dp" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal"
        android:weightSum="5">

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_ac"
            android:layout_weight="1"
            android:text="AC"
            android:background="#ff0000"
            android:textColor="#000"
            android:textSize="20dp"
            android:layout_margin="5dp" />

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_left"
            android:layout_weight="1"
            android:text="("
            android:background="#fff"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_right"
            android:layout_weight="1"
            android:text=")"
            android:background="#fff"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_divide"
            android:layout_weight="1"
            android:text="/"
            android:background="#fffaf0"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_del"
            android:layout_weight="1"
            android:text="DEL"
            android:background="#808a87"
            android:textColor="#000"
            android:textSize="15dp"
            android:layout_margin="5dp"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal"
        android:weightSum="4">

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_7"
            android:layout_weight="1"
            android:text="7"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_8"
            android:layout_weight="1"
            android:text="8"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_9"
            android:layout_weight="1"
            android:text="9"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_mult"
            android:layout_weight="1"
            android:text="*"
            android:background="#fffaf0"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal"
        android:weightSum="4">

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_4"
            android:layout_weight="1"
            android:text="4"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_5"
            android:layout_weight="1"
            android:text="5"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_6"
            android:layout_weight="1"
            android:text="6"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_add"
            android:layout_weight="1"
            android:text="+"
            android:background="#fffaf0"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal"
        android:weightSum="4">

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_1"
            android:layout_weight="1"
            android:text="1"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_2"
            android:layout_weight="1"
            android:text="2"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_3"
            android:layout_weight="1"
            android:text="3"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_minus"
            android:layout_weight="1"
            android:text="-"
            android:background="#fffaf0"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal"
        android:weightSum="4">

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_0"
            android:layout_weight="2"
            android:text="0"
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_dot"
            android:layout_weight="1"
            android:text="."
            android:textColor="#000"
            android:textSize="30dp"
            android:layout_margin="5dp"/>

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:id="@+id/button_result"
            android:layout_weight="1"
            android:text="="
            android:background="#ff6347"
            android:textColor="#fff"
            android:textSize="30dp"
            android:layout_margin="5dp"/>
    </LinearLayout>

</LinearLayout>
  • 解析

1、布局使用LinearLayout布局,android:orientation="vertical"指定垂直布局,从上至下依次是表达式显示框,结果显示框以及五行按钮,并指定总权重方便控制显示。

2、文本框TextView使用android:gravity="right|bottom"指定其从右下开始显示内容。

3、在按钮上,使用android:background="#ff0000"指定按钮背景颜色,使用android:layout_margin="5dp"控制偏移,使其不会过于紧凑。(关于按钮背景颜色无法设置,可在res//values//themes.xml文件下将代码<style name="Theme.Calculation" parent="Theme.MaterialComponents.DayNight.DarkActionBar.">改为<style name="Theme.Calculation" parent="Theme.MaterialComponents.DayNight.DarkActionBar.Bridge">)

二、计算器逻辑设计

  • 代码部分

package com.example.calculation;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.TypedValue;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.math.BigDecimal;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private final StringBuilder sb = new StringBuilder();//用于表达式的输入
    private String expression = "";//最终表达式的确定
    private String result = "";//计算结果
    private boolean isHasDot = false;//是否有小数点
    private final Stack<Boolean> dotStack = new Stack<>();
    //用栈存储每一个数字是否有小数点
    private boolean isZero = false;//是否是数字零
    private final Stack<Boolean> zeroStack = new Stack<>();
    private int leftNum = 0;//左括号数量
    private int rightNum = 0;//右括号数量
    private TextView textView;
    private TextView result_view;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = (TextView) findViewById(R.id.text_view);
        textView.setAutoSizeTextTypeUniformWithConfiguration(4, 70, 10, TypedValue.COMPLEX_UNIT_DIP);
        //将显示框设置为根据行数自动缩小
        result_view = (TextView) findViewById(R.id.result_view);
        result_view.setAutoSizeTextTypeUniformWithConfiguration(4, 70, 10, TypedValue.COMPLEX_UNIT_DIP);
        Button button1 = (Button) findViewById(R.id.button_1);
        button1.setOnClickListener(this);
        Button button2 = (Button) findViewById(R.id.button_2);
        button2.setOnClickListener(this);
        Button button3 = (Button) findViewById(R.id.button_3);
        button3.setOnClickListener(this);
        Button button4 = (Button) findViewById(R.id.button_4);
        button4.setOnClickListener(this);
        Button button5 = (Button) findViewById(R.id.button_5);
        button5.setOnClickListener(this);
        Button button6 = (Button) findViewById(R.id.button_6);
        button6.setOnClickListener(this);
        Button button7 = (Button) findViewById(R.id.button_7);
        button7.setOnClickListener(this);
        Button button8 = (Button) findViewById(R.id.button_8);
        button8.setOnClickListener(this);
        Button button9 = (Button) findViewById(R.id.button_9);
        button9.setOnClickListener(this);
        Button button0 = (Button) findViewById(R.id.button_0);
        button0.setOnClickListener(this);
        Button buttondot = (Button) findViewById(R.id.button_dot);
        buttondot.setOnClickListener(this);
        Button buttonadd = (Button) findViewById(R.id.button_add);
        buttonadd.setOnClickListener(this);
        Button buttonminus = (Button) findViewById(R.id.button_minus);
        buttonminus.setOnClickListener(this);
        Button buttonmult = (Button) findViewById(R.id.button_mult);
        buttonmult.setOnClickListener(this);
        Button buttondivide = (Button) findViewById(R.id.button_divide);
        buttondivide.setOnClickListener(this);
        Button buttonac = (Button) findViewById(R.id.button_ac);
        buttonac.setOnClickListener(this);
        Button buttondel = (Button) findViewById(R.id.button_del);
        buttondel.setOnClickListener(this);
        Button buttonleft = (Button) findViewById(R.id.button_left);
        buttonleft.setOnClickListener(this);
        Button buttonright = (Button) findViewById(R.id.button_right);
        buttonright.setOnClickListener(this);
        Button buttonresult = (Button) findViewById(R.id.button_result);
        buttonresult.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        result_view.setText("");
        switch (v.getId()) {
            case R.id.button_1:
                if (isZero == true) {
                    sb.deleteCharAt(sb.length() - 1);
                    isZero = false;
                }
                sb.append('1');
                textView.setText(sb.toString());
                break;
            case R.id.button_2:
                if (isZero == true) {
                    sb.deleteCharAt(sb.length() - 1);
                    isZero = false;
                }
                sb.append('2');
                textView.setText(sb.toString());
                break;
            case R.id.button_3:
                if (isZero == true) {
                    sb.deleteCharAt(sb.length() - 1);
                    isZero = false;
                }
                sb.append('3');
                textView.setText(sb.toString());
                break;
            case R.id.button_4:
                if (isZero == true) {
                    sb.deleteCharAt(sb.length() - 1);
                    isZero = false;
                }
                sb.append('4');
                textView.setText(sb.toString());
                break;
            case R.id.button_5:
                if (isZero == true) {
                    sb.deleteCharAt(sb.length() - 1);
                    isZero = false;
                }
                sb.append('5');
                textView.setText(sb.toString());
                break;
            case R.id.button_6:
                if (isZero == true) {
                    sb.deleteCharAt(sb.length() - 1);
                    isZero = false;
                }
                sb.append('6');
                textView.setText(sb.toString());
                break;
            case R.id.button_7:
                if (isZero == true) {
                    sb.deleteCharAt(sb.length() - 1);
                    isZero = false;
                }
                sb.append('7');
                textView.setText(sb.toString());
                break;
            case R.id.button_8:
                if (isZero == true) {
                    sb.deleteCharAt(sb.length() - 1);
                    isZero = false;
                }
                sb.append('8');
                textView.setText(sb.toString());
                break;
            case R.id.button_9:
                if (isZero == true) {
                    sb.deleteCharAt(sb.length() - 1);
                    isZero = false;
                }
                sb.append('9');
                textView.setText(sb.toString());
                break;
            case R.id.button_0:
                if (isZero == false) {
                    sb.append('0');
                    if (sb.length() == 1 ||
                            !('0' <= sb.charAt(sb.length() - 2) && sb.charAt(sb.length() - 2) <= '9')
                                    && sb.charAt(sb.length() - 2) != '.') {
                        isZero = true;
                    }
                }
                textView.setText(sb.toString());
                break;
            case R.id.button_dot:
                if (isHasDot == false) {
                    if (sb.length() == 0 ||
                            !('0' <= sb.charAt(sb.length() - 1) && sb.charAt(sb.length() - 1) <= '9')) {
                        sb.append("0.");
                    } else {
                        sb.append('.');
                    }
                    isHasDot = true;
                    isZero = false;
                }
                textView.setText(sb.toString());
                break;
            case R.id.button_add:
                if (sb.length() != 0 &&
                        (sb.charAt(sb.length() - 1) == '+' || sb.charAt(sb.length() - 1) == '-' || sb.charAt(sb.length() - 1) == '*' || sb.charAt(sb.length() - 1) == '/')) {
                    sb.setCharAt(sb.length() - 1, '+');
                } else if (sb.length() != 0) {
                    sb.append('+');
                    zeroStack.push(isZero);
                    dotStack.push(isHasDot);
                    isZero = false;
                    isHasDot = false;
                }
                if (result.matches("[-]?\\d+[.]?\\d*") && sb.length() == 0) {
                    sb.append(result + "+");
                    isHasDot = result.matches("[-]?\\d*[.]\\d*");
                    isZero = "0".equals(result);
                    zeroStack.push(isZero);
                    dotStack.push(isHasDot);
                    isZero = false;
                    isHasDot = false;
                }
                textView.setText(sb.toString());
                break;
            case R.id.button_minus:
                if (sb.length() != 0 &&
                        (sb.charAt(sb.length() - 1) == '+' || sb.charAt(sb.length() - 1) == '-' || sb.charAt(sb.length() - 1) == '*' || sb.charAt(sb.length() - 1) == '/')) {
                    sb.append('(');
                    zeroStack.push(isZero);
                    dotStack.push(isHasDot);
                    leftNum++;
                }
                if (result.matches("[-]?\\d+[.]?\\d*") && sb.length() == 0) {
                    sb.append(result + "-");
                    isHasDot = result.matches("[-]?\\d*[.]\\d*");
                    isZero = "0".equals(result);
                    zeroStack.push(isZero);
                    dotStack.push(isHasDot);
                    isZero = false;
                    isHasDot = false;
                }
                sb.append('-');
                zeroStack.push(isZero);
                dotStack.push(isHasDot);
                isZero = false;
                isHasDot = false;
                textView.setText(sb.toString());
                break;
            case R.id.button_mult:
                if (sb.length() != 0 &&
                        (sb.charAt(sb.length() - 1) == '+' || sb.charAt(sb.length() - 1) == '-' || sb.charAt(sb.length() - 1) == '*' || sb.charAt(sb.length() - 1) == '/')) {
                    sb.setCharAt(sb.length() - 1, '*');
                } else if (sb.length() != 0) {
                    sb.append('*');
                    zeroStack.push(isZero);
                    dotStack.push(isHasDot);
                    isZero = false;
                    isHasDot = false;
                }
                if (result.matches("[-]?\\d+[.]?\\d*") && sb.length() == 0) {
                    sb.append(result + "*");
                    isHasDot = result.matches("[-]?\\d*[.]\\d*");
                    isZero = "0".equals(result);
                    zeroStack.push(isZero);
                    dotStack.push(isHasDot);
                    isZero = false;
                    isHasDot = false;
                }
                textView.setText(sb.toString());
                break;
            case R.id.button_divide:
                if (sb.length() != 0 &&
                        (sb.charAt(sb.length() - 1) == '+' || sb.charAt(sb.length() - 1) == '-' || sb.charAt(sb.length() - 1) == '*' || sb.charAt(sb.length() - 1) == '/')) {
                    sb.setCharAt(sb.length() - 1, '/');
                } else if (sb.length() != 0) {
                    sb.append('/');
                    zeroStack.push(isZero);
                    dotStack.push(isHasDot);
                    isZero = false;
                    isHasDot = false;
                }
                if (result.matches("[-]?\\d+[.]?\\d*") && sb.length() == 0) {
                    sb.append(result + "/");
                    isHasDot = result.matches("[-]?\\d*[.]\\d*");
                    isZero = "0".equals(result);
                    zeroStack.push(isZero);
                    dotStack.push(isHasDot);
                    isZero = false;
                    isHasDot = false;
                }
                textView.setText(sb.toString());
                break;
            case R.id.button_left:
                sb.append('(');
                leftNum++;
                zeroStack.push(isZero);
                dotStack.push(isHasDot);
                isZero = false;
                isHasDot = false;
                textView.setText(sb.toString());
                break;
            case R.id.button_right:
                sb.append(')');
                rightNum++;
                zeroStack.push(isZero);
                dotStack.push(isHasDot);
                isZero = false;
                isHasDot = false;
                textView.setText(sb.toString());
                break;
            case R.id.button_del:
                if (sb.length() != 0) {
                    if (sb.charAt(sb.length() - 1) == '.') {
                        isHasDot = false;
                        if (sb.charAt(sb.length() - 2) == '0') {
                            sb.deleteCharAt(sb.length() - 1);
                        }
                    }
                    if (sb.charAt(sb.length() - 1) == '(') {
                        leftNum--;
                    }
                    if (sb.charAt(sb.length() - 1) == ')') {
                        rightNum--;
                    }
                    if (sb.charAt(sb.length() - 1) == '0' && isZero == true) {
                        isZero = false;
                    }
                    if (!(sb.charAt(sb.length() - 1) == '.' || '0' <= sb.charAt(sb.length() - 1) && sb.charAt(sb.length() - 1) <= '9')) {
                        if (!dotStack.isEmpty()) {
                            isHasDot = dotStack.pop();
                        }
                        if (!zeroStack.isEmpty()) {
                            isZero = zeroStack.pop();
                        }
                    }
                    sb.deleteCharAt(sb.length() - 1);
                }
                result_view.setText("");
                textView.setText(sb.toString());
                break;
            case R.id.button_ac:
                if (sb.length() != 0) {
                    sb.delete(0, sb.length());
                }
                isHasDot = false;
                isZero = false;
                zeroStack.clear();
                dotStack.clear();
                expression = "";
                result = "";
                leftNum = 0;
                rightNum = 0;
                result_view.setText("");
                textView.setText("");
                break;
            case R.id.button_result:
                if (sb.length() != 0) {
                    textView.setText(sb.toString());
                    isHasDot = false;
                    isZero = false;
                    zeroStack.clear();
                    dotStack.clear();
                    if (leftNum < rightNum) {
                        result = "出错";
                        sb.delete(0, sb.length());
                        result_view.setText(result);
                        leftNum = 0;
                        rightNum = 0;
                        break;
                    } else if (leftNum > rightNum) {
                        while (leftNum > rightNum) {
                            sb.append(')');
                            rightNum++;
                        }
                    }
                    if (sb.charAt(0) == '-') {
                        sb.insert(0, '0');
                    }
                    if (sb.charAt(sb.length() - 1) == '+' || sb.charAt(sb.length() - 1) == '-') {
                        sb.append('0');
                    }
                    if (sb.charAt(sb.length() - 1) == '*' || sb.charAt(sb.length() - 1) == '/') {
                        sb.append('1');
                    }
                    for (int i = 1; i < sb.length() - 1; i++) {
                        char ch = sb.charAt(i);
                        if (ch == '(' && (sb.charAt(i - 1) == '.' || '0' <= sb.charAt(i - 1) && sb.charAt(i - 1) <= '9')) {
                            sb.insert(i, '*');
                        }
                        if (ch == ')' && '0' <= sb.charAt(i + 1) && sb.charAt(i + 1) <= '9') {
                            sb.insert(i + 1, '*');
                        }
                    }
                    expression = sb.toString();
                    sb.delete(0, sb.length());
                    exchange(expression);
                    expression = "";
                    leftNum = 0;
                    rightNum = 0;
                }
                result_view.setText(result);
                break;
        }
    }

    public void exchange(String expression) {
        Queue<Object> queue = new LinkedList<>();
        Stack<Character> stack = new Stack<>();
        int figureNum = 0;
        int operatorNum = 0;
        StringBuilder numSb = new StringBuilder();
        for (int i = 0; i < expression.length(); i++) {
            char ch = expression.charAt(i);
            if (ch == '.' || ('0' <= ch && ch <= '9')) {
                numSb.append(ch);
            } else {
                if (numSb.length() != 0) {
                    queue.offer(new BigDecimal(numSb.toString()));
                    figureNum++;
                    numSb.delete(0, numSb.length());
                }
                if (ch == '-' && expression.charAt(i - 1) == '(' &&
                        ('0' <= expression.charAt(i + 1) && expression.charAt(i + 1) <= '9')) {
                    numSb.append(ch);
                    continue;
                }
                if (ch == '(') {
                    stack.push(ch);
                } else if ((ch == '+' || ch == '-') && !stack.isEmpty() && stack.peek() == '(') {
                    stack.push(ch);
                } else if ((ch == '*' || ch == '/') && !stack.isEmpty() && !(stack.peek() == '*' || stack.peek() == '/')) {
                    stack.push(ch);
                } else {
                    while (!stack.empty() && stack.peek() != '(') {
                        queue.offer(stack.pop());
                        operatorNum++;
                    }
                    if (!stack.isEmpty()) {
                        stack.pop();
                    }
                    if (ch != ')') {
                        stack.push(ch);
                    }
                }
            }
        }
        if (numSb.length() != 0) {
            queue.offer(new BigDecimal(numSb.toString()));
            figureNum++;
        }
        while (!stack.empty()) {
            queue.offer(stack.pop());
            operatorNum++;
        }
        if (figureNum == operatorNum + 1) {
            calculate(queue);
        } else {
            result = "出错";
        }
    }

    public void calculate(Queue<Object> queue) {
        Stack<BigDecimal> stack = new Stack<>();
        while (!queue.isEmpty()) {
            Object obj = queue.poll();
            if (obj.getClass() == Character.class) {
                char operator = (Character) obj;
                BigDecimal num1 = (BigDecimal) stack.pop();
                BigDecimal num2 = (BigDecimal) stack.pop();
                BigDecimal subResult;
                if (operator == '+') {
                    subResult = num2.add(num1);
                    stack.push(subResult);
                } else if (operator == '-') {
                    subResult = num2.subtract(num1);
                    stack.push(subResult);
                } else if (operator == '*') {
                    subResult = num2.multiply(num1);
                    stack.push(subResult);
                } else {
                    if ("0".equals(num1.toString())) {
                        result = "不能除以零";
                        return;
                    } else if ("0".equals(num2.toString())) {
                        stack.push(new BigDecimal("0"));
                    } else {
                        subResult = num2.divide(num1, 20, BigDecimal.ROUND_HALF_UP);
                        stack.push(subResult);
                    }
                }
            } else {
                stack.push((BigDecimal) obj);
            }
        }
        result = stack.pop().toString();
        if (result.matches("[-]?\\d*[.]\\d*")) {
            int i = result.length() - 1;
            while (result.charAt(i) == '0') {
                i--;
            }
            if (result.charAt(i) == '.') {
                i--;
            }
            result = result.substring(0, i + 1);
        }
    }
}
  • 分析

1、expression,result,textview等会多次使用,因此将其设置为成员变量。
2、显示框根据行数自动放大或缩小。使用textView.setAutoSizeTextTypeUniformWithConfiguration(4, 70, 10, TypedValue.COMPLEX_UNIT_DIP);方法控制。第一个参数表示最小大小,第二个参数表示最大大小,第三个参数表示每次缩小步长,第四个参数表示之前参数的单位(如:dp,sp等)。

  • 按钮点击详解

3、除了按下等号键显示计算结果,其余按键都不需要显示,因此将结果显示框设为空。
4、输入数字时,如果前一个是数字“0”,按下其他数字应显示该数字,即显示“1”而不是“01”。
5、按下加减运算符时,如果之前有计算结果,应直接使用该结果运算。
6、表达式优化:以“-”号开头的表达式,可以在前加上零方便计算;如果左括号少于右括号,此表达式无法计算;左括号少于右括号,可以在末尾补全右括号;表达式以“+”“-”号结尾,应补上0,以“*”“/”结尾,应补上1;对于a(b),(a)b应自动补上乘号

  • 中缀表达式转后缀表达式

1、遇到数字以及小数点直接保存,遇到符号按照优先级顺序出栈入栈。
2、使用计数器分别记录运算符和数字的个数,如果不匹配,直接显示出错

  • 计算

1、在除法运算中,“0/a”应直接显示0、“a/0”应不计算,直接显示不能除以零
2、在最后结果上,“2.000000&hellip;”的类似有末尾0的结果应去除末尾0以及小数点

以上就是“Android如何实现计算器功能”这篇文章的所有内容,感谢各位的阅读!相信大家阅读完这篇文章都有很大的收获,小编每天都会为大家更新不同的知识,如果还想学习更多的知识,请关注亿速云行业资讯频道。

向AI问一下细节

免责声明:本站发布的内容(图片、视频和文字)以原创、转载和分享为主,文章观点不代表本网站立场,如果涉及侵权请联系站长邮箱:is@yisu.com进行举报,并提供相关证据,一经查实,将立刻删除涉嫌侵权内容。

AI