androidstudio实现简单的计算器功能

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>


 
 
 
 
 
 
 
 


 


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

 

 

 

 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

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