用android studio写一个简单的计算器
16lz
2021-01-26
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，若添加背景图请看Android Studio App设置背景图片
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"?> strings.xml（content_main.xml代码中的一些变量在此代码中定义的）：
Calculator Settings page2 下一页 0 1 2 3 4 5 6 7 8 9 + - * / CE <- = 请输入： 结果: . 计算式 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更多相关文章
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