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: 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: android:layout_width='match_parent' android:layout_height='wrap_content' android:layout_gravity='center' android:editable='false' android:hint='@string/shuru' /> <EditText android: 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: android:layout_width='wrap_content' android:layout_height='wrap_content' android:layout_alignParentLeft='true' android:text='@string/clear' android:textSize='40sp' /> <Button android: android:layout_width='wrap_content' android:layout_height='wrap_content' android:layout_toRightOf='@id/clear' android:text='@string/back' android:textSize='40sp' /> <Button android: android:layout_width='wrap_content' android:layout_height='wrap_content' android:layout_toRightOf='@id/back' android:text='@string/divide' android:textSize='40sp' /> <Button android: android:layout_width='wrap_content' android:layout_height='wrap_content' android:layout_toRightOf='@id/divide' android:text='@string/multiply' android:textSize='40sp' /> <Button android: 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: 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: 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: 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: 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: 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: 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: 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: 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: 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: 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: 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: 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: 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。

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