android studio实现简单的计算器(无bug)

<?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:background="@drawable/jsj1">
 <TextView
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:text="计算器"
 android:textSize="20dp"
 android:gravity="center"
 android:textColor="#EE4000"/>
 <TextView
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:text="输入数字"/>
 <EditText
 android:id="@ id/ET001"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"/>
 <TextView
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:text="运算结果"/>
 <EditText
 android:id="@ id/ET002"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"/>
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:orientation="horizontal">
 <Button
  android:layout_marginLeft="5dp"
  android:id="@ id/btn001"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="C"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/qqqqqqqqqq"/>
 <Button
  android:id="@ id/btn002"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="÷"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/qqqqqqqqqq"/>

 <Button
  android:id="@ id/btn003"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="×"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/qqqqqqqqqq"/>
 <Button
  android:id="@ id/btn004"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="Cx"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/qqqqqqqqqq"/>

 </LinearLayout>
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:orientation="horizontal">
 <Button
  android:layout_marginLeft="5dp"
  android:id="@ id/btn005"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="7"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn006"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="8"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn007"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="9"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn008"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="-"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/qqqqqqqqqq"/>

 </LinearLayout>
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:orientation="horizontal">
 <Button
  android:layout_marginLeft="5dp"
  android:id="@ id/btn009"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="4"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn0010"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="5"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn0011"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="6"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn0012"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text=" "
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/qqqqqqqqqq"/>

 </LinearLayout>
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:orientation="horizontal">
 <Button
  android:layout_marginLeft="5dp"
  android:id="@ id/btn0013"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="1"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn0014"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="2"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn0015"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="3"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn0019"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="."
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/qqqqqqqqqq"/>

 </LinearLayout>

 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:orientation="horizontal">
 <Button
  android:layout_marginLeft="5dp"
  android:id="@ id/btn0018"
  android:layout_width="88dp"
  android:layout_height="100dp"
  android:text="0"
  android:textSize="20dp"
  android:padding="5dp"
  android:background="@drawable/sssssssssssssss"/>
 <Button
  android:id="@ id/btn0016"
  android:layout_width="265dp"
  android:layout_height="100dp"
  android:text="="
  android:textSize="20dp"
  android:padding="5dp"
  android:background="#6495ED"/>

 

 </LinearLayout>
</LinearLayout>

package com.example.myzhuoye;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

public class JiSuanJi extends AppCompatActivity implements View.OnClickListener {
 //结果
 private EditText ET001,ET002;
 //数字0-9
 private Button btn0018, btn0013,btn0014,btn0015,btn009,btn0010,btn0011,btn005,btn006,btn007;
 //运算符, ,-,×，÷,.,=;清除,返回
 private Button btn0012,btn008,btn003,btn002,btn0019,btn0016,btn001,btn004;
 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(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.layout4);
 //结果
 ET001=(EditText)findViewById(R.id.ET001);
 ET002=(EditText)findViewById(R.id.ET002);
 //数字0-9
 btn0013=(Button)findViewById(R.id.btn0013);
 btn0014=(Button)findViewById(R.id.btn0014);
 btn0015=(Button)findViewById(R.id.btn0015);
 btn009=(Button)findViewById(R.id.btn009);
 btn0010=(Button)findViewById(R.id.btn0010);
 btn0011=(Button)findViewById(R.id.btn0011);
 btn005=(Button)findViewById(R.id.btn005);
 btn006=(Button)findViewById(R.id.btn006);
 btn007=(Button)findViewById(R.id.btn007);
 btn0018=(Button)findViewById(R.id.btn0018);
 //运算符
 btn004=(Button)findViewById(R.id.btn004);
 btn0012=(Button)findViewById(R.id.btn0012);
 btn008=(Button)findViewById(R.id.btn008);
 btn003=(Button)findViewById(R.id.btn003);
 btn002=(Button)findViewById(R.id.btn002);
 btn0019=(Button)findViewById(R.id.btn0019);
 btn0016=(Button)findViewById(R.id.btn0016);
 btn001=(Button)findViewById(R.id.btn001);
 //添加点击事件
 btn0013.setOnClickListener((View.OnClickListener) this);
 btn0014.setOnClickListener((View.OnClickListener) this);
 btn0015.setOnClickListener((View.OnClickListener) this);
 btn009.setOnClickListener((View.OnClickListener) this);
 btn0010.setOnClickListener((View.OnClickListener) this);

 btn0011.setOnClickListener((View.OnClickListener) this);
 btn005.setOnClickListener((View.OnClickListener) this);
 btn006.setOnClickListener((View.OnClickListener) this);
 btn007.setOnClickListener((View.OnClickListener) this);
 btn0018.setOnClickListener((View.OnClickListener) this);

 btn0012.setOnClickListener((View.OnClickListener) this);
 btn008.setOnClickListener((View.OnClickListener) this);
 btn003.setOnClickListener((View.OnClickListener) this);
 btn002.setOnClickListener((View.OnClickListener) this);
 btn0019.setOnClickListener((View.OnClickListener) this);

 btn0016.setOnClickListener((View.OnClickListener) this);
 btn001.setOnClickListener((View.OnClickListener) this);
 btn004.setOnClickListener((View.OnClickListener) this);
 }

 @Override
 public void onClick(View v) {
 String string=ET001.getText().toString();
 switch (v.getId()){
  case R.id.btn0018://0
  num(0);
  break;
  case R.id.btn0013://1
  num(1);
  break;
  case R.id.btn0014://2
  num(2);
  break;
  case R.id.btn0015://3
  num(3);
  break;
  case R.id.btn009://4
  num(4);
  break;
  case R.id.btn0010://5
  num(5);
  break;
  case R.id.btn0011://6
  num(6);
  break;
  case R.id.btn005://7
  num(7);
  break;
  case R.id.btn006://8
  num(8);
  break;
  case R.id.btn007://9
  num(9);
  break;
  case R.id.btn0019://.
  dot();
  break;
  case R.id.btn0012:// 
  add();
  break;
  case R.id.btn008://-
  sub();
  break;
  case R.id.btn003://"*"
  multiply();
  break;
  case R.id.btn002://除
  divide();
  break;
  case R.id.btn001://清除
  clear();
  break;
  case R.id.btn004://返回
  back();
  break;
  //计算结果
  case R.id.btn0016://结果
  result();
  break;
  default:
  break;
 }
 ET001.setText(text);
 ET002.setText(String.valueOf(result));
 }
 private void num(int i) {
 text = text   String.valueOf(i);
 }

 private void dot() {

 int a=text.length();
 String s01=" ";
 String s02="-";
 String s03="×";
 String s04="÷";
 String s05=".";
 if (a!=0) {
  String s=text.substring(a-1,a);
  String s0=text.substring(0,a-1);
  if (s01.equals(s) || s02.equals(s) || s03.equals(s) || s04.equals(s) || s05.equals(s)) {
  text = s0 ".";
  }else {
  text  = ".";
  }
 } else {
  text = "";
  result =0.0;
  ET001.setText("");
  ET002.setText("");
 }
 }

 private void clear() {

 text = "";
 result =0.0;
 ET001.setText("");
 ET002.setText("");

 }

 private void back() {
 if (text.length()!=0){
  String str = text.substring(0, text.length()-1);
  text = str;
 }

 ;

 }

 private void add() {
 int a=text.length();

 String s01=" ";
 String s02="-";
 String s03="×";
 String s04="÷";
 String s05=".";
 if (a!=0) {
  String s=text.substring(a-1,a);
  String s0=text.substring(0,a-1);
  if (s01.equals(s) || s02.equals(s) || s03.equals(s) || s04.equals(s) || s05.equals(s)) {
  text = s0 " ";
  }else {
  text  = " ";
  }
 } else {
  text = "";
  result =0.0;
  ET001.setText("");
  ET002.setText("");
 }

 }

 private void sub() {
 int a=text.length();
 String s01=" ";
 String s02="-";
 String s03="×";
 String s04="÷";
 String s05=".";
 if (a!=0) {
  String s=text.substring(a-1,a);
  String s0=text.substring(0,a-1);
  if (s01.equals(s) || s02.equals(s) || s03.equals(s) || s04.equals(s) || s05.equals(s)) {
  text = s0 "-";
  }else {
  text  = "-";
  }
 } else {
  text = "";
  result =0.0;
  ET001.setText("");
  ET002.setText("");
 }

 }

 private void multiply() {

 int a=text.length();
 String s01=" ";
 String s02="-";
 String s03="×";
 String s04="÷";
 String s05=".";
 if (a!=0) {
  String s=text.substring(a-1,a);
  String s0=text.substring(0,a-1);
  if (s01.equals(s) || s02.equals(s) || s03.equals(s) || s04.equals(s) || s05.equals(s)) {
  text = s0 "×";
  }else {
  text  = "×";
  }
 } else {
  text = "";
  result =0.0;
  ET001.setText("");
  ET002.setText("");
 }

 }

 private void divide() {

 int a=text.length();
 String s01=" ";
 String s02="-";
 String s03="×";
 String s04="÷";
 String s05=".";
 if (a!=0) {
  String s=text.substring(a-1,a);
  String s0=text.substring(0,a-1);
  if (s01.equals(s) || s02.equals(s) || s03.equals(s) || s04.equals(s) || s05.equals(s)) {
  text = s0 "÷";
  }else {
  text  = "÷";
  }
 } else {
  text = "";
  result =0.0;
  ET001.setText("");
  ET002.setText("");
 }
 }

 //计算输出结果
 private void result() {
 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;
 }

}

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
 <gradient android:startColor="#c0000000" android:endColor="#c0000000" android:angle="90" /><!--背景颜色渐变 angle为渐变角度-->
 <solid android:color=" #8DEEEE" /><!-- 背景填充颜色 -->
 <stroke android:width="0.5dp" android:color="#ff000000" /><!-- 描边，边框宽度、颜色 -->
 <corners android:radius="0dp" /><!-- 边角圆弧的半径 -->
 <padding android:left="0dp" android:top="0dp" android:right="0dp" android:bottom="0dp" /><!-- 四周留出来的空白 -->
</shape>

<?xml version="1.0" encoding="utf-8"?>

<shape xmlns:android="http://schemas.android.com/apk/res/android">
<gradient android:startColor="#c0000000" android:endColor="#c0000000" android:angle="90" /><!--背景颜色渐变 angle为渐变角度-->
<solid android:color="#00FFFF" /><!-- 背景填充颜色 -->
<stroke android:width="0.5dp" android:color="#ff000000" /><!-- 描边，边框宽度、颜色 -->
<corners android:radius="0dp" /><!-- 边角圆弧的半径 -->
<padding android:left="0dp" android:top="0dp" android:right="0dp" android:bottom="0dp" /><!-- 四周留出来的空白 -->
</shape>