android studio实现简单的计算器功能

本文实例为大家分享了android studio实现计算器的具体代码，供大家参考，具体内容如下

先来个效果图：

功能： 满足加减乘除四则运算规则，有回退、清除功能。

下面的代码只是完成基本功能，若添加背景图先看看下面的方法：android studio app设置背景图片

1、本地准备好图片，复制它，粘贴进mipmap（drawable）文件夹。

2、在activity_main.xml里添加下面代码，注意添加位置。

3、完成，效果图：

content_main.xml文件（页面布局，content_main.xml代码包含在activity_main.xml文件中）：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.constraintlayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/next"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 app:layout_behavior="@string/appbar_scrolling_view_behavior"
 tools:context=".mainactivity"
 tools:showin="@layout/activity_main">

 <!--<textview-->
 <!--android:layout_width="wrap_content"-->
 <!--android:layout_height="wrap_content"-->
 <!--android:text="hello world!"-->
 <!--app:layout_constraintbottom_tobottomof="parent"-->
 <!--app:layout_constraintleft_toleftof="parent"-->
 <!--app:layout_constraintright_torightof="parent"-->
 <!--app:layout_constrainttop_totopof="parent" />-->


 <linearlayout
 android:layout_width="fill_parent"
 android:layout_height="match_parent"
 android:orientation="vertical" >


 <edittext
 android:id="@+id/input"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:layout_gravity="center"
 android:editable="false"
 android:hint="@string/shuru" />

 <edittext
 android:id="@+id/output"
 android:layout_width="match_parent"
 android:layout_height="70dp"
 android:layout_gravity="center"
 android:editable="true"
 android:gravity="right"
 android:hint="@string/shuchu" />

 <relativelayout
 android:layout_width="350dp"
 android:layout_height="wrap_content"
 android:layout_gravity="center">

 <button
  android:id="@+id/clear"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignparentleft="true"
  android:text="@string/clear"
  android:textsize="40sp" />

 <button
  android:id="@+id/back"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_torightof="@id/clear"
  android:text="@string/back"
  android:textsize="40sp" />

 <button
  android:id="@+id/divide"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_torightof="@id/back"
  android:text="@string/divide"
  android:textsize="40sp" />

 <button
  android:id="@+id/multiply"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_torightof="@id/divide"
  android:text="@string/multiply"
  android:textsize="40sp" />

 <button
  android:id="@+id/seven"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignparentleft="true"
  android:layout_below="@id/clear"
  android:text="@string/seven"
  android:textsize="40sp" />

 <button
  android:id="@+id/eight"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_torightof="@id/seven"
  android:layout_below="@id/divide"
  android:text="@string/eight"
  android:textsize="40sp" />

 <button
  android:id="@+id/nine"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@id/multiply"
  android:layout_torightof="@id/eight"
  android:text="@string/nine"
  android:textsize="40sp" />

 <button
  android:id="@+id/subtract"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignparentright="true"
  android:layout_below="@id/multiply"
  android:layout_torightof="@id/nine"
  android:text="@string/subtract"
  android:textsize="40sp" />

 <button
  android:id="@+id/four"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignparentleft="true"
  android:layout_below="@id/seven"
  android:text="@string/four"
  android:textsize="40sp" />

 <button
  android:id="@+id/five"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@id/eight"
  android:layout_torightof="@id/four"
  android:text="@string/five"
  android:textsize="40sp" />

 <button
  android:id="@+id/six"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@id/nine"
  android:layout_torightof="@id/five"
  android:text="@string/six"
  android:textsize="40sp" />

 <button
  android:id="@+id/add"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignparentright="true"
  android:layout_below="@id/subtract"
  android:layout_torightof="@id/six"
  android:text="@string/add"
  android:textsize="40sp" />

 <button
  android:id="@+id/one"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignparentleft="true"

  android:layout_below="@id/four"
  android:text="@string/one"
  android:textsize="40sp" />

 <button
  android:id="@+id/two"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@id/five"
  android:layout_torightof="@id/one"
  android:text="@string/two"
  android:textsize="40sp" />

 <button
  android:id="@+id/three"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@id/six"
  android:layout_torightof="@id/two"
  android:text="@string/three"
  android:textsize="40sp" />

 <button
  android:id="@+id/result"
  android:layout_width="wrap_content"
  android:layout_height="146dp"
  android:layout_alignparentright="true"
  android:layout_below="@id/add"
  android:layout_torightof="@id/three"
  android:text="@string/result"
  android:textsize="40sp" />


 <button
  android:id="@+id/zero"
  android:layout_width="175dp"
  android:layout_height="wrap_content"
  android:layout_alignparentleft="true"
  android:layout_below="@id/one"
  android:text="@string/zero"
  android:textsize="40sp" />

 <button
  android:id="@+id/dot"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@id/three"
  android:layout_torightof="@id/zero"
  android:text="@string/dot"
  android:textsize="40sp" />

 </relativelayout>

 </linearlayout>


</android.support.constraint.constraintlayout>

strings.xml（content_main.xml代码中的一些变量在此代码中定义的）：

<resources>
 <string name="app_name">calculator</string>
 <string name="action_settings">settings</string>
 <string name="title_activity_page2">page2</string>

 <string name="next">下一页</string>
 <string name="zero">0</string>
 <string name="one">1</string>
 <string name="two">2</string>
 <string name="three">3</string>
 <string name="four">4</string>
 <string name="five">5</string>
 <string name="six">6</string>
 <string name="seven">7</string>
 <string name="eight">8</string>
 <string name="nine">9</string>
 <string name="add">+</string>
 <string name="subtract">-</string>
 <string name="multiply">*</string>
 <string name="divide">/</string>
 <string name="clear">ce</string>
 <string name="back">&#60;-</string>
 <string name="result">=</string>
 <string name="shuru">请输入：</string>
 <string name="shuchu">结果:</string>
 <string name="dot">.</string>
 <string name="resulttext">计算式</string>

</resources>

mainactivity.java（计算器中实现计算功能的核心代码）：

package com.example.dell.calculator;

import android.content.intent;
import android.os.bundle;
import android.support.design.widget.floatingactionbutton;
import android.support.design.widget.snackbar;
import android.support.v7.app.appcompatactivity;
import android.support.v7.widget.toolbar;
import android.view.view;
import android.view.menu;
import android.view.menuitem;

import android.app.activity;
import android.content.context;
import android.view.view.onclicklistener;
import android.widget.checkbox;
import android.widget.edittext;
import android.widget.button;
import java.io.fileinputstream;
import java.io.filenotfoundexception;
import java.io.fileoutputstream;
import java.io.ioexception;

import java.text.decimalformat;
import java.text.numberformat;
import java.util.regex.matcher;
import java.util.regex.pattern;


public class mainactivity extends appcompatactivity {

 private edittext output = null;
 private edittext input = null;
 private button btn0 = null;
 private button btn1 = null;
 private button btn2 = null;
 private button btn3 = null;
 private button btn4 = null;
 private button btn5 = null;
 private button btn6 = null;
 private button btn7 = null;
 private button btn8 = null;
 private button btn9 = null;
 private button btnadd = null;
 private button btnsubtract = null;
 private button btnmultiply = null;
 private button btndivide = null;
 private button btnclear = null;
 private button btnback = null;
 private button btndot = null;
 private button btnresult = null;

 private string text = "";//保存输入的数字和符号
 private double result = 0.0;//输出结果

 @override
 protected void oncreate(bundle savedinstancestate) {
 super.oncreate(savedinstancestate);
 setcontentview(r.layout.activity_main);
 toolbar toolbar = (toolbar) findviewbyid(r.id.toolbar);
 setsupportactionbar(toolbar);

 output = (edittext) findviewbyid(r.id.output);
 input = (edittext) findviewbyid(r.id.input);

 btn0 = (button) findviewbyid(r.id.zero);
 btn1 = (button) findviewbyid(r.id.one);
 btn2 = (button) findviewbyid(r.id.two);
 btn3 = (button) findviewbyid(r.id.three);
 btn4 = (button) findviewbyid(r.id.four);
 btn5 = (button) findviewbyid(r.id.five);
 btn6 = (button) findviewbyid(r.id.six);
 btn7 = (button) findviewbyid(r.id.seven);
 btn8 = (button) findviewbyid(r.id.eight);
 btn9 = (button) findviewbyid(r.id.nine);
 btnadd = (button) findviewbyid(r.id.add);
 btnsubtract = (button) findviewbyid(r.id.subtract);
 btnmultiply = (button) findviewbyid(r.id.multiply);
 btndivide = (button) findviewbyid(r.id.divide);
 btnclear = (button) findviewbyid(r.id.clear);
 btnback = (button) findviewbyid(r.id.back);
 btndot = (button) findviewbyid(r.id.dot);
 btnresult = (button) findviewbyid(r.id.result);

 //设置按钮侦听事件
 btn0.setonclicklistener(listener);
 btn1.setonclicklistener(listener);
 btn2.setonclicklistener(listener);
 btn3.setonclicklistener(listener);
 btn4.setonclicklistener(listener);
 btn5.setonclicklistener(listener);
 btn6.setonclicklistener(listener);
 btn7.setonclicklistener(listener);
 btn8.setonclicklistener(listener);
 btn9.setonclicklistener(listener);

 btnadd.setonclicklistener(listener);
 btnsubtract.setonclicklistener(listener);
 btnmultiply.setonclicklistener(listener);
 btndivide.setonclicklistener(listener);
 btnclear.setonclicklistener(listener);
 btnback.setonclicklistener(listener);
 btndot.setonclicklistener(listener);
 btnresult.setonclicklistener(listener);


 floatingactionbutton fab = (floatingactionbutton) findviewbyid(r.id.fab);
 fab.setonclicklistener(new view.onclicklistener() {
  @override
  public void onclick(view view) {
  snackbar.make(view, "replace with your own action", snackbar.length_long)
   .setaction("action", null).show();
  }
 });
 }

 @override
 public boolean oncreateoptionsmenu(menu menu) {
 // inflate the menu; this adds items to the action bar if it is present.
 getmenuinflater().inflate(r.menu.menu_main, menu);
 return true;
 }

 @override
 public boolean onoptionsitemselected(menuitem item) {
 // handle action bar item clicks here. the action bar will
 // automatically handle clicks on the home/up button, so long
 // as you specify a parent activity in androidmanifest.xml.
 int id = item.getitemid();

 //noinspection simplifiableifstatement
 if (id == r.id.action_settings) {
  return true;
 }

 return super.onoptionsitemselected(item);
 }


 //public void onclicknext(view view) {
 // intent intent = new intent(this,page2.class);
 // startactivity(intent);
 // }


 private onclicklistener listener = new onclicklistener() {

 public void onclick(view v) {
  // todo auto-generated method stub
  switch (v.getid()) {
  //输入数字
  case r.id.zero:
   num(0);
   break;
  case r.id.one:
   num(1);
   break;
  case r.id.two:
   num(2);
   break;
  case r.id.three:
   num(3);
   break;
  case r.id.four:
   num(4);
   break;
  case r.id.five:
   num(5);
   break;
  case r.id.six:
   num(6);
   break;
  case r.id.seven:
   num(7);
   break;
  case r.id.eight:
   num(8);
   break;
  case r.id.nine:
   num(9);
   break;

  case r.id.dot:
  dot();
  break;
  //执行运算
  case r.id.add:
   add();
   break;
  case r.id.subtract:
   sub();
   break;
  case r.id.multiply:
   multiply();
   break;
  case r.id.divide:
   divide();
   break;
  case r.id.clear:
   clear();
   break;
  case r.id.back:
   back();
   break;
  //计算结果
  case r.id.result:
   result();
   break;

  default:
   break;

  }
  input.settext(text);
  output.settext(string.valueof(result));

 }
 };

 private void num(int i) {
 // todo auto-generated method stub
 text = text + string.valueof(i);
 }

 private void dot() {
 // todo auto-generated method stub

 text = text + ".";
 }

 private void clear() {
 // todo auto-generated method stub

 text = "";
 result = null;
 input.settext("");
 output.settext("");

 }

 private void back() {
 // todo auto-generated method stub

 string str = text.substring(0, text.length()-1);
 text = str;

 }

 private void add() {
 // todo auto-generated method stub

 text += "+";

 }

 private void sub() {
 // todo auto-generated method stub

 text += "-";

 }

 private void multiply() {
 // todo auto-generated method stub

 text += "*";

 }

 private void divide() {
 // todo auto-generated method stub

 text += "/";
 }

 //计算输出结果
 private void result() {
 // todo auto-generated method stub
 result = testoperation(text);
 }


 public double testoperation(string s){
 //分割字符然后放进数组
 string s1 =s.replace("+","-");
 string[] str = s1.split("-");
 double total1=0;
 //先遍历数组，把里面的乘除结果算出来
 for(string str1:str){
  if(str1.contains("*")||str1.contains("/")){
  double total = 0;
  for(int i =0;i<str1.length();){
   int count =1;
   a:for(int j =i+1;j<str1.length();j++){
   char c =str1.charat(j);
   if(c=='*'||c=='/'){
    break a;
   }else{
    count++;
   }
   }

   //将数字截取出来
   string s2 =str1.substring(i,i+count);
   double d = double.parsedouble(s2);
   if(i==0){
   total = d;
   }else{
   char c1 = str1.charat(i-1);
   if(c1=='*'){
    total*=d;
   }else if(c1=='/'){
    //如果除数为0，直接返回null;
    if(d == 0)
    return null;
    total/=d;
   }
   }
   i+=count+1;
  }
  s= s.replace(str1, total+"");
  }
 }
 //进行加减运算
 for(int i =0;i<s.length();i++){
  int count =1;
  a:for(int j=i+1;j<s.length();j++){
  char c = s.charat(j);
  if(c=='+'||c=='-'){
   break a;
  }else{
   count++;
  }
  }
  string s3= s.substring(i,i+count);
  double d2 = double.parsedouble(s3);
  if(i==0){
  total1 = d2;
  }else{
  char c = s.charat(i-1);
  if(c=='+'){
   total1+=d2;
  }else if(c=='-'){
   total1-=d2;
  }
  }
  i+=count;
 }
 return total1;
 }

}

更多计算器功能实现，请点击专题： 计算器功能汇总 进行学习

关于android计算器功能的实现，查看专题：android计算器 进行学习。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。