前言

提示：Kotlin版本＋Java版本

这学期学习了Android开发，写的第一个小项目就是简易计算器。原本只写了kotlin版本，放假后加了Java版本，在此记录下。

计算器的功能包括【加减乘除、求余】，功能比较简单，所以是简易计算器。

计算器效果如图：

简易计算器

一、Kotlin版本

示例：pandas 是基于NumPy 的一种工具，该工具是为了解决数据分析任务而创建的。

1. activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayoutxmlns: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/main_layout"android:layout_width="match_parent"android:layout_height="match_parent"android:background="#1a1c21"tools:context=".MainActivity"><androidx.constraintlayout.widget.Guidelineandroid:id="@+id/guideline1"android:layout_width="wrap_content"android:layout_height="wrap_content"android:orientation="horizontal"app:layout_constraintGuide_begin="167dp" /><androidx.constraintlayout.widget.Guidelineandroid:id="@+id/guideline2"android:layout_width="wrap_content"android:layout_height="wrap_content"android:orientation="horizontal"app:layout_constraintGuide_begin="261dp" /><TextViewandroid:id="@+id/process_text_view"android:layout_width="0dp"android:layout_height="0dp"android:layout_marginStart="20dp"android:layout_marginEnd="20dp"android:gravity="bottom|end"android:letterSpacing="0.1"android:text="16x16"android:textColor="#f4f0f2"android:textSize="25sp"app:layout_constraintBottom_toTopOf="@+id/guideline1"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="1.0"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent"app:layout_constraintVertical_bias="0.0" /><TextViewandroid:id="@+id/result_text_view"android:layout_width="0dp"android:layout_height="0dp"android:layout_marginStart="20dp"android:layout_marginEnd="20dp"android:gravity="end|center_vertical"android:letterSpacing="0.1"android:text="196"android:textColor="@color/white"android:textSize="30sp"app:layout_constraintBottom_toTopOf="@+id/guideline2"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="@+id/guideline1" /><TextViewandroid:id="@+id/btn_view"android:layout_width="0dp"android:layout_height="0dp"android:background="@drawable/top_round_shape"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.0"app:layout_constraintLeft_toLeftOf="parent"app:layout_constraintRight_toRightOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/result_text_view"app:layout_constraintVertical_bias="0.0" /><TextViewandroid:id="@+id/mod_view"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="operatorButtonClicked"android:text="@string/percent"android:textColor="#d74b51"android:textSize="25sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/div_view"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_M"app:layout_constraintTop_toBottomOf="@+id/result_text_view" /><TextViewandroid:id="@+id/view_M"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="mButtonClicked"android:text="@string/M"android:textColor="#29d1b2"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_9"app:layout_constraintEnd_toStartOf="@+id/mod_view"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/del_view"app:layout_constraintTop_toBottomOf="@+id/result_text_view" /><TextViewandroid:id="@+id/view_7"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_7"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_4"app:layout_constraintEnd_toStartOf="@+id/view_8"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/ac_view" /><TextViewandroid:id="@+id/view_8"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_8"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_5"app:layout_constraintEnd_toStartOf="@+id/view_9"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_7"app:layout_constraintTop_toBottomOf="@+id/del_view" /><TextViewandroid:id="@+id/view_4"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_4"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_1"app:layout_constraintEnd_toStartOf="@+id/view_5"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/view_7" /><TextViewandroid:id="@+id/view_1"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_1"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_0"app:layout_constraintEnd_toStartOf="@+id/view_2"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/view_4" /><TextViewandroid:id="@+id/view_0"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_0"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toStartOf="@+id/dot_view"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/view_1" /><TextViewandroid:id="@+id/view_3"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_3"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/equal_view"app:layout_constraintEnd_toStartOf="@+id/add_view"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_2"app:layout_constraintTop_toBottomOf="@+id/view_6" /><TextViewandroid:id="@+id/view_5"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_5"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_2"app:layout_constraintEnd_toStartOf="@+id/view_6"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_4"app:layout_constraintTop_toBottomOf="@+id/view_8" /><TextViewandroid:id="@+id/equal_view"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="equalButtonClicked"android:text="@string/equal"android:textColor="#ffff00"android:textSize="30sp"android:textStyle="bold"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toStartOf="@+id/sub_view"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/dot_view"app:layout_constraintTop_toBottomOf="@+id/view_3" /><TextViewandroid:id="@+id/dot_view"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="dotButtonClicked"android:text="@string/dot"android:textColor="@color/white"android:textSize="30sp"android:textStyle="bold"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toStartOf="@+id/equal_view"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_0"app:layout_constraintTop_toBottomOf="@+id/view_2" /><TextViewandroid:id="@+id/add_view"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="operatorButtonClicked"android:text="@string/add"android:textColor="#d74b51"android:textSize="35sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/sub_view"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_3"app:layout_constraintTop_toBottomOf="@+id/mul_view" /><TextViewandroid:id="@+id/sub_view"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="operatorButtonClicked"android:text="@string/sub"android:textColor="#d74b51"android:textSize="35sp"android:textStyle="bold"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/equal_view"app:layout_constraintTop_toBottomOf="@+id/add_view" /><TextViewandroid:id="@+id/view_2"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_2"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/dot_view"app:layout_constraintEnd_toStartOf="@+id/view_3"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_1"app:layout_constraintTop_toBottomOf="@+id/view_5" /><TextViewandroid:id="@+id/mul_view"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="operatorButtonClicked"android:text="@string/mul"android:textColor="#d74b51"android:textSize="35sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/add_view"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_6"app:layout_constraintTop_toBottomOf="@+id/div_view" /><TextViewandroid:id="@+id/view_6"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_6"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_3"app:layout_constraintEnd_toStartOf="@+id/mul_view"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_5"app:layout_constraintTop_toBottomOf="@+id/view_9" /><TextViewandroid:id="@+id/ac_view"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="clearButtonClicked"android:text="@string/AC"android:textColor="#29d1b2"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_7"app:layout_constraintEnd_toStartOf="@+id/del_view"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/result_text_view" /><TextViewandroid:id="@+id/view_9"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="numberButtonClicked"android:text="@string/num_9"android:textColor="@color/white"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_6"app:layout_constraintEnd_toStartOf="@+id/div_view"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_8"app:layout_constraintTop_toBottomOf="@+id/view_M" /><TextViewandroid:id="@+id/div_view"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="operatorButtonClicked"android:text="@string/div"android:textColor="#d74b51"android:textSize="35sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/mul_view"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/view_9"app:layout_constraintTop_toBottomOf="@+id/mod_view" /><TextViewandroid:id="@+id/del_view"android:layout_width="80dp"android:layout_height="80dp"android:background="@drawable/round_shape"android:gravity="center"android:onClick="delButtonClicked"android:text="@string/Del"android:textColor="#29d1b2"android:textSize="22sp"android:textStyle="bold"app:layout_constraintBottom_toTopOf="@+id/view_8"app:layout_constraintEnd_toStartOf="@+id/view_M"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/ac_view"app:layout_constraintTop_toBottomOf="@+id/result_text_view" /><ImageViewandroid:id="@+id/lightMode"android:layout_width="60dp"android:layout_height="60dp"android:layout_marginTop="5dp"android:layout_marginEnd="5dp"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintTop_toTopOf="parent"app:srcCompat="@drawable/mode_ic" />
</androidx.constraintlayout.widget.ConstraintLayout>

2. MainActivity.kt

package com.example.my_counterimport android.os.Bundle
import android.util.Log
import android.view.View
import android.widget.TextView
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.example.my_counter.databinding.ActivityMainBindingclass MainActivity : AppCompatActivity() {private val currentInputNumString = StringBuilder()private val numbersList = mutableListOf<Double>()private val operatorsList = mutableListOf<String>()private val dotsList = mutableListOf(false)private var isNumStart = trueprivate lateinit var processTextView: TextViewprivate lateinit var resultTextView: TextViewoverride fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)val binding = ActivityMainBinding.inflate(layoutInflater)setContentView(binding.root)processTextView = binding.processTextViewresultTextView = binding.resultTextView}fun numberButtonClicked(view: View) {val tv = view as TextViewif (currentInputNumString.toString() == "0") {currentInputNumString.clear()}// 更新text view内容currentInputNumString.append(tv.text)processTextView.text = currentInputNumString.toString()if (isNumStart) {isNumStart = false}}fun operatorButtonClicked(view: View) {val tv = view as TextViewval myOperators = listOf('+', '-', '×', '÷', '%')val digits = listOf('0', '1', '2', '3', '4', '5', '6', '7', '8', '9')// 如果前一个符号为运算符，则更换运算符when {currentInputNumString[currentInputNumString.length - 1] in myOperators -> {currentInputNumString.deleteCharAt(currentInputNumString.length - 1)currentInputNumString.append(tv.text)}currentInputNumString[currentInputNumString.length - 1] in digits -> {// 如果前一个符号为数字currentInputNumString.append(tv.text.toString())processTextView.text = currentInputNumString.toString()isNumStart = truedotsList.add(false)}else -> {Toast.makeText(this, "此刻不能添加${tv.text}!", Toast.LENGTH_SHORT).show()}}processTextView.text = currentInputNumString.toString()Log.v("myTag", "$operatorsList")}fun clearButtonClicked(view: View) {currentInputNumString.clear()currentInputNumString.append("0")processTextView.text = currentInputNumString.toString()// 重置列表、参数isNumStart = truedotsList.clear()dotsList.add(false)}fun delButtonClicked(view: View) {val myOperators = listOf('+', '-', '×', '÷', '%')// 若输入串为NULL，则不进行操作if (currentInputNumString.isNotEmpty()) {if (currentInputNumString[currentInputNumString.length - 1] in myOperators) {isNumStart = falsedotsList.removeLast()} else if (currentInputNumString[currentInputNumString.length - 1] == '.') {dotsList[dotsList.size - 1] = false} else {if (currentInputNumString.length >= 2 && currentInputNumString[currentInputNumString.length - 2] in myOperators) {isNumStart = true//dotsList.removeLast()} else if(currentInputNumString.length == 1){isNumStart = true}}currentInputNumString.deleteCharAt(currentInputNumString.length - 1)processTextView.text = currentInputNumString.toString()}}fun dotButtonClicked(view: View) {if (!dotsList[dotsList.size - 1]) {val tv = view as TextViewif (currentInputNumString.isEmpty()) {currentInputNumString.append("0")}currentInputNumString.append(tv.text.toString())processTextView.text = currentInputNumString.toString()dotsList[dotsList.size - 1] = true}}fun equalButtonClicked(view: View) {if (currentInputNumString.isEmpty()) {resultTextView.text = "0"return}var resNum = 0.0var i = 0var temp = 0.0val numStr = StringBuilder()val firstOperators = listOf("×", "÷", "%")val operators = listOf('×', '÷', '%', '+', '-')// 构造numbersList、operatorsListnumbersList.clear()operatorsList.clear()while (i < currentInputNumString.length) {if (currentInputNumString[i] in operators) {numbersList.add(numStr.toString().toDouble())operatorsList.add(currentInputNumString[i].toString())numStr.clear()} else {numStr.append(currentInputNumString[i])}i++}if (numStr.isNotEmpty()) {numbersList.add(numStr.toString().toDouble())} else {operatorsList.removeLast()}// 进行乘除运算i = 0while (i < operatorsList.size) {if (operatorsList[i] in firstOperators) {when (operatorsList[i]) {"×" -> temp = numbersList[i] * numbersList[i + 1]"÷" -> temp = numbersList[i] / numbersList[i + 1]"%" -> temp = numbersList[i] % numbersList[i + 1]}operatorsList.removeAt(i)numbersList[i + 1] = tempnumbersList.removeAt(i)} else {i++}}// 进行加减运算i = 0resNum = numbersList[i]numbersList.removeAt(0)while (i < operatorsList.size) {if (operatorsList[i] == "+") {resNum += numbersList[i]} else {resNum -= numbersList[i]}i++}// 显示结果val resStr = resNum.toString()val ii = resStr.indexOf('.')var flagInt = truefor (a in ii + 1 until resStr.length) {if (resStr[a] != '0') {flagInt = falsebreak}}if (flagInt) {    // 显示整数resultTextView.text = resNum.toInt().toString()} else {  // 显示浮点数resultTextView.text = resNum.toString()}Log.v("myTag", "$numbersList")Log.v("myTag", "$operatorsList")}fun mButtonClicked(view: View) {// 更新显示processTextView.text = resultTextView.text// 更新字符串currentInputNumString.clear()currentInputNumString.append(resultTextView.text.toString())// 重置dotsList列表dotsList.clear()dotsList.add(false)// 标记是否数字开头isNumStart = false// 判断是否为小数val numStr = resultTextView.text.toString()val i = numStr.indexOf('.')if (i > 0) {dotsList[0] = true}}
}

二、Java版本

1. activity_main.xml

提示：其实两个版本的布局文件都差不多，只是颜色和背景有区别而已。直接用Kotlin版本的activity_main.xml，再修改下颜色、背景即可。

2. MainActivity.java

代码如下：

package com.example.zhangskin;import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;import com.zhy.changeskin.SkinManager;import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;public class MainActivity extends com.zhy.changeskin.base.BaseSkinActivity implements View.OnClickListener {private int signal = 0;private final StringBuilder currentInputNumString = new StringBuilder();private final ArrayList<Double> numbersList = new ArrayList<>();private final ArrayList<String> operatorsList = new ArrayList<>();private final ArrayList<Boolean> dotsList = new ArrayList<>();private Boolean isNumStart = true;private TextView processTextView;private TextView resultTextView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 换肤第三方库注册，可直接注释掉SkinManager.getInstance().init(this);dotsList.add(false);processTextView = findViewById(R.id.process_text_view);resultTextView = findViewById(R.id.result_text_view);// 绑定监听事件findViewById(R.id.view_0).setOnClickListener(this);findViewById(R.id.view_1).setOnClickListener(this);findViewById(R.id.view_2).setOnClickListener(this);findViewById(R.id.view_3).setOnClickListener(this);findViewById(R.id.view_4).setOnClickListener(this);findViewById(R.id.view_5).setOnClickListener(this);findViewById(R.id.view_6).setOnClickListener(this);findViewById(R.id.view_7).setOnClickListener(this);findViewById(R.id.view_8).setOnClickListener(this);findViewById(R.id.view_9).setOnClickListener(this);findViewById(R.id.view_M).setOnClickListener(this);findViewById(R.id.ac_view).setOnClickListener(this);findViewById(R.id.del_view).setOnClickListener(this);findViewById(R.id.add_view).setOnClickListener(this);findViewById(R.id.sub_view).setOnClickListener(this);findViewById(R.id.mul_view).setOnClickListener(this);findViewById(R.id.div_view).setOnClickListener(this);findViewById(R.id.mod_view).setOnClickListener(this);findViewById(R.id.dot_view).setOnClickListener(this);findViewById(R.id.equal_view).setOnClickListener(this);// bringToFront()让控件始终在最顶层，不被覆盖                     findViewById(R.id.lightMode).bringToFront();// 换肤操作，可直接注释掉findViewById(R.id.lightMode).setOnClickListener(view -> {if(signal == 0){signal = 1;SkinManager.getInstance().changeSkin("night");}else{signal = 0;SkinManager.getInstance().removeAnySkin();}});}@Overridepublic void onClick(View view) {switch (view.getId()){case R.id.view_0:case R.id.view_1:case R.id.view_2:case R.id.view_3:case R.id.view_4:case R.id.view_5:case R.id.view_6:case R.id.view_7:case R.id.view_8:case R.id.view_9:numberButtonClicked(view);break;case R.id.add_view:case R.id.sub_view:case R.id.mul_view:case R.id.div_view:case R.id.mod_view:operatorButtonClicked(view);break;case R.id.ac_view:clearButtonClicked(view);break;case R.id.del_view:delButtonClicked(view);break;case R.id.view_M:mButtonClicked(view);break;case R.id.dot_view:dotButtonClicked(view);break;case R.id.equal_view:equalButtonClicked(view);break;default:break;}}public void numberButtonClicked(View v){TextView tv = (TextView) v;if (currentInputNumString.toString().equals("0")) {currentInputNumString.delete(0,currentInputNumString.length());}// 更新text view内容currentInputNumString.append(tv.getText());processTextView.setText(currentInputNumString.toString());if (isNumStart) {isNumStart = false;}}public void operatorButtonClicked(View view) {TextView tv = (TextView) view;List<Character> myOperators = Arrays.asList('+', '-', '×', '÷', '%');List<Character> digits = Arrays.asList('0', '1', '2', '3', '4', '5', '6', '7', '8', '9');// 如果前一个符号为运算符，则更换运算符if(myOperators.contains(currentInputNumString.charAt(currentInputNumString.length() - 1))) {currentInputNumString.deleteCharAt(currentInputNumString.length() - 1);currentInputNumString.append(tv.getText());}else if(digits.contains(currentInputNumString.charAt(currentInputNumString.length() - 1))){// 如果前一个符号为数字currentInputNumString.append(tv.getText().toString());processTextView.setText(currentInputNumString.toString());isNumStart = true;dotsList.add(false);}else {Toast.makeText(this, "此刻不能添加${tv.getText()}!", Toast.LENGTH_SHORT).show();}processTextView.setText(currentInputNumString.toString());}public void clearButtonClicked(View view) {currentInputNumString.delete(0,currentInputNumString.length());currentInputNumString.append("0");processTextView.setText(currentInputNumString.toString());// 重置列表、参数isNumStart = true;dotsList.clear();dotsList.add(false);}public void delButtonClicked(View view) {List<Character> myOperators = Arrays.asList('+', '-', '×', '÷', '%');// 若输入串为NULL，则不进行操作if (currentInputNumString.length()>0) {char temp = currentInputNumString.charAt(currentInputNumString.length() - 1);if (myOperators.contains(temp)) {isNumStart = false;dotsList.remove(dotsList.size()-1);//dotsList.removeLast();} else if ('.' == currentInputNumString.charAt(currentInputNumString.length() - 1)) {dotsList.set(dotsList.size() - 1, false);} else {if (currentInputNumString.length() >= 2 &&myOperators.contains(currentInputNumString.charAt(currentInputNumString.length() - 2))) {isNumStart = true;} else if(currentInputNumString.length() == 1){isNumStart = true;}}currentInputNumString.deleteCharAt(currentInputNumString.length() - 1);processTextView.setText(currentInputNumString.toString());}}public void dotButtonClicked(View view) {if (!dotsList.get(dotsList.size() - 1)) {TextView tv = (TextView) view;if (currentInputNumString.length() == 0) {currentInputNumString.append("0");}currentInputNumString.append(".");processTextView.setText(currentInputNumString.toString());dotsList.set(dotsList.size() - 1, true);}}public void mButtonClicked(View view) {// 更新显示processTextView.setText(resultTextView.getText());// 更新字符串currentInputNumString.delete(0,currentInputNumString.length());currentInputNumString.append(resultTextView.getText().toString());// 重置dotsList列表dotsList.clear();dotsList.add(false);// 标记是否数字开头isNumStart = false;// 判断是否为小数String numStr = resultTextView.getText().toString();int i = numStr.indexOf('.');if (i > 0) {dotsList.set(0, true);}}public void equalButtonClicked(View view) {if (currentInputNumString.length() == 0 ) {resultTextView.setText("0");return;}double resNum = 0.0;int i = 0;double temp = 0.0;StringBuilder numStr = new StringBuilder();List<String> firstOperators = Arrays.asList("×", "÷", "%");List<Character> operators = Arrays.asList('×', '÷', '%', '+', '-');// 构造numbersList、operatorsListnumbersList.clear();operatorsList.clear();while (i < currentInputNumString.length()) {if (operators.contains(currentInputNumString.charAt(i))) {numbersList.add(Double.parseDouble(numStr.toString()));operatorsList.add(Character.toString(currentInputNumString.charAt(i)));numStr.delete(0,numStr.length());} else {numStr.append(currentInputNumString.charAt(i));}i++;}if (numStr.length()>0) {numbersList.add(Double.parseDouble(numStr.toString()));} else {operatorsList.remove(operatorsList.size()-1);}// 进行乘除运算i = 0;while (i < operatorsList.size()) {if (firstOperators.contains(operatorsList.get(i))){switch (operatorsList.get(i)) {case "×":temp = numbersList.get(i) * numbersList.get(i + 1);break;case "÷":temp = numbersList.get(i) / numbersList.get(i + 1);break;case "%":temp = numbersList.get(i) % numbersList.get(i + 1);break;}operatorsList.remove(i);numbersList.set(i+1,temp);numbersList.remove(i);} else {i++;}}// 进行加减运算i = 0;resNum = numbersList.get(i);numbersList.remove(0);while (i < operatorsList.size()) {if (operatorsList.get(i).equals("+")) {resNum += numbersList.get(i);} else {resNum -= numbersList.get(i);}i++;}// 显示结果String resStr = Double.toString(resNum);int ii = resStr.indexOf('.');boolean flagInt = true;for (int a = ii + 1;a < resStr.length();a++) {if (resStr.charAt(a) != '0') {flagInt = false;break;}}if (flagInt) {    // 显示整数resultTextView.setText(String.valueOf((int)resNum));} else {  // 显示浮点数resultTextView.setText(String.valueOf(resNum));}}
}