用多个Activity实现分别实现加、减、乘、除的计算器代码

好的，以下是用多个Activity实现加、减、乘、除的计算器代码：

MainActivity.java：

public class MainActivity extends AppCompatActivity {
    private EditText etNum1, etNum2;
    private Button btnAdd, btnSubtract, btnMultiply, btnDivide;
    
    @Override
    protected void onCreate(Bundle savedInstanceState

相关问题

android实现一个简易多功能计算器代码和布局文件

以下是一个简单的 Android 计算器的布局文件和代码：

layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    
    <TextView
        android:id="@+id/tv_result"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:padding="16dp"
        android:gravity="right"
        android:textColor="@android:color/black" />
        
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        
        <Button
            android:id="@+id/btn_clear"
            android:text="C"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_divide"
            android:text="/"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_multiply"
            android:text="*"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_minus"
            android:text="-"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
    </LinearLayout>
    
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        
        <Button
            android:id="@+id/btn_7"
            android:text="7"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_8"
            android:text="8"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_9"
            android:text="9"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_plus"
            android:text="+"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
    </LinearLayout>
    
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        
        <Button
            android:id="@+id/btn_4"
            android:text="4"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_5"
            android:text="5"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_6"
            android:text="6"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_equals"
            android:text="="
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
    </LinearLayout>
    
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        
        <Button
            android:id="@+id/btn_1"
            android:text="1"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_2"
            android:text="2"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_3"
            android:text="3"
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
            
        <Button
            android:id="@+id/btn_decimal"
            android:text="."
            android:textSize="24sp"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content" />
    </LinearLayout>
    
    <Button
        android:id="@+id/btn_0"
        android:text="0"
        android:textSize="24sp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
        
</LinearLayout>

Java/MainActivity.java

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private TextView tvResult;
    private Button btnClear, btnDivide, btnMultiply, btnMinus, btnPlus, btnEquals, btnDecimal;
    private Button btn0, btn1, btn2, btn3, btn4, btn5, btn6, btn7, btn8, btn9;
    
    private String currentNumber = "";
    private String operation = "";
    private double result = 0.0;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        tvResult = findViewById(R.id.tv_result);
        btnClear = findViewById(R.id.btn_clear);
        btnDivide = findViewById(R.id.btn_divide);
        btnMultiply = findViewById(R.id.btn_multiply);
        btnMinus = findViewById(R.id.btn_minus);
        btnPlus = findViewById(R.id.btn_plus);
        btnEquals = findViewById(R.id.btn_equals);
        btnDecimal = findViewById(R.id.btn_decimal);
        
        btn0 = findViewById(R.id.btn_0);
        btn1 = findViewById(R.id.btn_1);
        btn2 = findViewById(R.id.btn_2);
        btn3 = findViewById(R.id.btn_3);
        btn4 = findViewById(R.id.btn_4);
        btn5 = findViewById(R.id.btn_5);
        btn6 = findViewById(R.id.btn_6);
        btn7 = findViewById(R.id.btn_7);
        btn8 = findViewById(R.id.btn_8);
        btn9 = findViewById(R.id.btn_9);
        
        btnClear.setOnClickListener(this);
        btnDivide.setOnClickListener(this);
        btnMultiply.setOnClickListener(this);
        btnMinus.setOnClickListener(this);
        btnPlus.setOnClickListener(this);
        btnEquals.setOnClickListener(this);
        btnDecimal.setOnClickListener(this);
        
        btn0.setOnClickListener(this);
        btn1.setOnClickListener(this);
        btn2.setOnClickListener(this);
        btn3.setOnClickListener(this);
        btn4.setOnClickListener(this);
        btn5.setOnClickListener(this);
        btn6.setOnClickListener(this);
        btn7.setOnClickListener(this);
        btn8.setOnClickListener(this);
        btn9.setOnClickListener(this);
    }
    
    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.btn_clear:
                currentNumber = "";
                operation = "";
                result = 0.0;
                tvResult.setText("");
                break;
                
            case R.id.btn_divide:
                performOperation("/");
                break;
                
            case R.id.btn_multiply:
                performOperation("*");
                break;
                
            case R.id.btn_minus:
                performOperation("-");
                break;
                
            case R.id.btn_plus:
                performOperation("+");
                break;
                
            case R.id.btn_equals:
                calculateResult();
                break;
                
            case R.id.btn_decimal:
                if (!currentNumber.contains(".")) {
                    currentNumber += ".";
                }
                tvResult.setText(currentNumber);
                break;
                
            case R.id.btn_0:
                appendNumber("0");
                break;
                
            case R.id.btn_1:
                appendNumber("1");
                break;
                
            case R.id.btn_2:
                appendNumber("2");
                break;
                
            case R.id.btn_3:
                appendNumber("3");
                break;
                
            case R.id.btn_4:
                appendNumber("4");
                break;
                
            case R.id.btn_5:
                appendNumber("5");
                break;
                
            case R.id.btn_6:
                appendNumber("6");
                break;
                
            case R.id.btn_7:
                appendNumber("7");
                break;
                
            case R.id.btn_8:
                appendNumber("8");
                break;
                
            case R.id.btn_9:
                appendNumber("9");
                break;
        }
    }
    
    private void appendNumber(String number) {
        currentNumber += number;
        tvResult.setText(currentNumber);
    }
    
    private void performOperation(String op) {
        if (operation.isEmpty()) {
            result = Double.parseDouble(currentNumber);
            operation = op;
            currentNumber = "";
        } else {
            calculateResult();
            operation = op;
        }
    }
    
    private void calculateResult() {
        if (operation.isEmpty()) {
            return;
        }
        
        double secondNumber = Double.parseDouble(currentNumber);
        
        switch (operation) {
            case "+":
                result += secondNumber;
                break;
                
            case "-":
                result -= secondNumber;
                break;
                
            case "*":
                result *= secondNumber;
                break;
                
            case "/":
                result /= secondNumber;
                break;
        }
        
        currentNumber = "";
        operation = "";
        tvResult.setText(String.valueOf(result));
    }
}

android studio实现计算器的加减乘除、乘方、开方

首先，在 Android Studio 中创建一个新项目，然后在布局文件中添加一个 TextView 和多个 Button，以实现计算器的界面。

接下来，在 MainActivity.java 中编写代码来实现计算器的功能。以下是一个简单的实现示例：

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import java.text.DecimalFormat;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private TextView mDisplayText;
    private Button mButton0, mButton1, mButton2, mButton3, mButton4, mButton5, mButton6, mButton7, mButton8, mButton9;
    private Button mButtonPlus, mButtonMinus, mButtonMultiply, mButtonDivide, mButtonPower, mButtonSqrt, mButtonEqual, mButtonClear;
    private String mNumber1 = "", mNumber2 = "", mOperator = "";
    private DecimalFormat mDecimalFormat;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mDisplayText = findViewById(R.id.display_text);
        mButton0 = findViewById(R.id.button_0);
        mButton1 = findViewById(R.id.button_1);
        mButton2 = findViewById(R.id.button_2);
        mButton3 = findViewById(R.id.button_3);
        mButton4 = findViewById(R.id.button_4);
        mButton5 = findViewById(R.id.button_5);
        mButton6 = findViewById(R.id.button_6);
        mButton7 = findViewById(R.id.button_7);
        mButton8 = findViewById(R.id.button_8);
        mButton9 = findViewById(R.id.button_9);
        mButtonPlus = findViewById(R.id.button_plus);
        mButtonMinus = findViewById(R.id.button_minus);
        mButtonMultiply = findViewById(R.id.button_multiply);
        mButtonDivide = findViewById(R.id.button_divide);
        mButtonPower = findViewById(R.id.button_power);
        mButtonSqrt = findViewById(R.id.button_sqrt);
        mButtonEqual = findViewById(R.id.button_equal);
        mButtonClear = findViewById(R.id.button_clear);

        mDecimalFormat = new DecimalFormat("#.##########");

        mButton0.setOnClickListener(this);
        mButton1.setOnClickListener(this);
        mButton2.setOnClickListener(this);
        mButton3.setOnClickListener(this);
        mButton4.setOnClickListener(this);
        mButton5.setOnClickListener(this);
        mButton6.setOnClickListener(this);
        mButton7.setOnClickListener(this);
        mButton8.setOnClickListener(this);
        mButton9.setOnClickListener(this);
        mButtonPlus.setOnClickListener(this);
        mButtonMinus.setOnClickListener(this);
        mButtonMultiply.setOnClickListener(this);
        mButtonDivide.setOnClickListener(this);
        mButtonPower.setOnClickListener(this);
        mButtonSqrt.setOnClickListener(this);
        mButtonEqual.setOnClickListener(this);
        mButtonClear.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.button_0:
                onNumberClicked("0");
                break;
            case R.id.button_1:
                onNumberClicked("1");
                break;
            case R.id.button_2:
                onNumberClicked("2");
                break;
            case R.id.button_3:
                onNumberClicked("3");
                break;
            case R.id.button_4:
                onNumberClicked("4");
                break;
            case R.id.button_5:
                onNumberClicked("5");
                break;
            case R.id.button_6:
                onNumberClicked("6");
                break;
            case R.id.button_7:
                onNumberClicked("7");
                break;
            case R.id.button_8:
                onNumberClicked("8");
                break;
            case R.id.button_9:
                onNumberClicked("9");
                break;
            case R.id.button_plus:
                onOperatorClicked("+");
                break;
            case R.id.button_minus:
                onOperatorClicked("-");
                break;
            case R.id.button_multiply:
                onOperatorClicked("*");
                break;
            case R.id.button_divide:
                onOperatorClicked("/");
                break;
            case R.id.button_power:
                onOperatorClicked("^");
                break;
            case R.id.button_sqrt:
                onOperatorClicked("sqrt");
                break;
            case R.id.button_equal:
                onEqualClicked();
                break;
            case R.id.button_clear:
                onClearClicked();
                break;
        }
    }

    private void onNumberClicked(String number) {
        if (mOperator.isEmpty()) {
            mNumber1 += number;
            mDisplayText.setText(mNumber1);
        } else {
            mNumber2 += number;
            mDisplayText.setText(mNumber2);
        }
    }

    private void onOperatorClicked(String operator) {
        if (!mNumber1.isEmpty() && mNumber2.isEmpty()) {
            mOperator = operator;
            mDisplayText.setText(mNumber1 + " " + operator + " ");
        }
    }

    private void onEqualClicked() {
        double result = 0.0;
        if (!mNumber1.isEmpty() && !mNumber2.isEmpty()) {
            double num1 = Double.parseDouble(mNumber1);
            double num2 = Double.parseDouble(mNumber2);
            switch (mOperator) {
                case "+":
                    result = num1 + num2;
                    break;
                case "-":
                    result = num1 - num2;
                    break;
                case "*":
                    result = num1 * num2;
                    break;
                case "/":
                    result = num1 / num2;
                    break;
                case "^":
                    result = Math.pow(num1, num2);
                    break;
            }
            mDisplayText.setText(mDecimalFormat.format(result));
            mNumber1 = mDecimalFormat.format(result);
            mNumber2 = "";
            mOperator = "";
        } else if (!mNumber1.isEmpty() && mNumber2.isEmpty() && mOperator.equals("sqrt")) {
            double num1 = Double.parseDouble(mNumber1);
            result = Math.sqrt(num1);
            mDisplayText.setText(mDecimalFormat.format(result));
            mNumber1 = mDecimalFormat.format(result);
            mNumber2 = "";
            mOperator = "";
        }
    }

    private void onClearClicked() {
        mNumber1 = "";
        mNumber2 = "";
        mOperator = "";
        mDisplayText.setText("");
    }
}

在这个示例代码中，我们实现了加、减、乘、除、乘方、开方等基本算术运算，并且使用 DecimalFormat 对结果进行格式化。当用户点击数字按钮时，我们将数字添加到当前操作数中；当用户点击操作符按钮时，我们将当前操作数视为第一个操作数，并将操作符保存；当用户点击等号按钮时，我们计算结果并在 TextView 中显示；当用户点击清除按钮时，我们将所有操作数和操作符都重置为初始状态。

最后，运行应用程序并测试计算器的功能。