andriod studio实现计算器代码

以下是一个简单的Android Studio计算器应用的代码示例：

XML布局文件：activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp">

    <TextView
        android:id="@+id/display"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:background="@android:color/darker_gray"
        android:padding="8dp"
        android:textColor="@android:color/white"
        android:textSize="24sp" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:weightSum="4">

        <Button
            android:id="@+id/button7"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="7"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button8"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="8"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button9"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="9"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button_divide"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="/"
            android:textSize="24sp" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:weightSum="4">

        <Button
            android:id="@+id/button4"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="4"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button5"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="5"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button6"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="6"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button_multiply"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="*"
            android:textSize="24sp" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:weightSum="4">

        <Button
            android:id="@+id/button1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="1"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button2"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="2"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button3"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="3"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button_minus"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="-"
            android:textSize="24sp" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:weightSum="4">

        <Button
            android:id="@+id/button_clear"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="C"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button0"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="0"
            android:textSize="24sp" />

        <Button
            android:id="@+id/button_dot"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="."
            android:textSize="24sp" />

        <Button
            android:id="@+id/button_plus"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="+"
            android:textSize="24sp" />

    </LinearLayout>

    <Button
        android:id="@+id/button_equals"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="="
        android:textSize="24sp" />

</LinearLayout>

Java代码文件：MainActivity.java

import androidx.appcompat.app.AppCompatActivity;

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

import java.text.DecimalFormat;

public class MainActivity extends AppCompatActivity {

    private TextView display;
    private Button button_clear, button_divide, button_multiply, button_minus, button_plus, button_equals,
            button_dot, button0, button1, button2, button3, button4, button5, button6, button7, button8, button9;

    private String currentNumber = "0";
    private String lastOperator = "";
    private double result = 0;

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

        display = findViewById(R.id.display);
        button_clear = findViewById(R.id.button_clear);
        button_divide = findViewById(R.id.button_divide);
        button_multiply = findViewById(R.id.button_multiply);
        button_minus = findViewById(R.id.button_minus);
        button_plus = findViewById(R.id.button_plus);
        button_equals = findViewById(R.id.button_equals);
        button_dot = findViewById(R.id.button_dot);
        button0 = findViewById(R.id.button0);
        button1 = findViewById(R.id.button1);
        button2 = findViewById(R.id.button2);
        button3 = findViewById(R.id.button3);
        button4 = findViewById(R.id.button4);
        button5 = findViewById(R.id.button5);
        button6 = findViewById(R.id.button6);
        button7 = findViewById(R.id.button7);
        button8 = findViewById(R.id.button8);
        button9 = findViewById(R.id.button9);

        button_clear.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                clear();
            }
        });

        button_divide.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                setOperator("/");
            }
        });

        button_multiply.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                setOperator("*");
            }
        });

        button_minus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                setOperator("-");
            }
        });

        button_plus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                setOperator("+");
            }
        });

        button_equals.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                calculate();
            }
        });

        button_dot.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!currentNumber.contains(".")) {
                    currentNumber += ".";
                    display.setText(currentNumber);
                }
            }
        });

        button0.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(0);
            }
        });

        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(1);
            }
        });

        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(2);
            }
        });

        button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(3);
            }
        });

        button4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(4);
            }
        });

        button5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(5);
            }
        });

        button6.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(6);
            }
        });

        button7.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(7);
            }
        });

        button8.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(8);
            }
        });

        button9.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addDigit(9);
            }
        });

    }

    private void clear() {
        currentNumber = "0";
        lastOperator = "";
        result = 0;
        display.setText(currentNumber);
    }

    private void setOperator(String operator) {
        if (lastOperator.equals("")) {
            result = Double.parseDouble(currentNumber);
        } else {
            calculate();
        }
        lastOperator = operator;
        currentNumber = "0";
    }

    private void addDigit(int digit) {
        if (currentNumber.equals("0")) {
            currentNumber = String.valueOf(digit);
        } else {
            currentNumber += String.valueOf(digit);
        }
        display.setText(currentNumber);
    }

    private void calculate() {
        double current = Double.parseDouble(currentNumber);
        switch (lastOperator) {
            case "+":
                result += current;
                break;
            case "-":
                result -= current;
                break;
            case "*":
                result *= current;
                break;
            case "/":
                result /= current;
                break;
        }
        DecimalFormat decimalFormat = new DecimalFormat("#.##########");
        currentNumber = decimalFormat.format(result);
        display.setText(currentNumber);
        lastOperator = "";
    }
}

这个计算器应用可以进行简单的加、减、乘、除运算，支持小数点输入和清零操作。