android studio 计算器实现 java

以下是一个简单的 Android Studio 计算器实现的 Java 代码：

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private TextView display;
    private Button buttonZero, buttonOne, buttonTwo, buttonThree, buttonFour, buttonFive, buttonSix, buttonSeven, buttonEight, buttonNine, buttonAdd, buttonSubtract, buttonMultiply, buttonDivide, buttonEqual, buttonClear;

    private float num1 = 0, num2 = 0;
    private boolean addition, subtraction, multiplication, division;

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

        display = findViewById(R.id.display);
        buttonZero = findViewById(R.id.button_zero);
        buttonOne = findViewById(R.id.button_one);
        buttonTwo = findViewById(R.id.button_two);
        buttonThree = findViewById(R.id.button_three);
        buttonFour = findViewById(R.id.button_four);
        buttonFive = findViewById(R.id.button_five);
        buttonSix = findViewById(R.id.button_six);
        buttonSeven = findViewById(R.id.button_seven);
        buttonEight = findViewById(R.id.button_eight);
        buttonNine = findViewById(R.id.button_nine);
        buttonAdd = findViewById(R.id.button_add);
        buttonSubtract = findViewById(R.id.button_subtract);
        buttonMultiply = findViewById(R.id.button_multiply);
        buttonDivide = findViewById(R.id.button_divide);
        buttonEqual = findViewById(R.id.button_equal);
        buttonClear = findViewById(R.id.button_clear);

        buttonZero.setOnClickListener(this);
        buttonOne.setOnClickListener(this);
        buttonTwo.setOnClickListener(this);
        buttonThree.setOnClickListener(this);
        buttonFour.setOnClickListener(this);
        buttonFive.setOnClickListener(this);
        buttonSix.setOnClickListener(this);
        buttonSeven.setOnClickListener(this);
        buttonEight.setOnClickListener(this);
        buttonNine.setOnClickListener(this);
        buttonAdd.setOnClickListener(this);
        buttonSubtract.setOnClickListener(this);
        buttonMultiply.setOnClickListener(this);
        buttonDivide.setOnClickListener(this);
        buttonEqual.setOnClickListener(this);
        buttonClear.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.button_zero:
                display.append("0");
                break;
            case R.id.button_one:
                display.append("1");
                break;
            case R.id.button_two:
                display.append("2");
                break;
            case R.id.button_three:
                display.append("3");
                break;
            case R.id.button_four:
                display.append("4");
                break;
            case R.id.button_five:
                display.append("5");
                break;
            case R.id.button_six:
                display.append("6");
                break;
            case R.id.button_seven:
                display.append("7");
                break;
            case R.id.button_eight:
                display.append("8");
                break;
            case R.id.button_nine:
                display.append("9");
                break;
            case R.id.button_add:
                if (display.getText().length() != 0) {
                    num1 = Float.parseFloat(display.getText().toString());
                    addition = true;
                    display.setText("");
                }
                break;
            case R.id.button_subtract:
                if (display.getText().length() != 0) {
                    num1 = Float.parseFloat(display.getText().toString());
                    subtraction = true;
                    display.setText("");
                }
                break;
            case R.id.button_multiply:
                if (display.getText().length() != 0) {
                    num1 = Float.parseFloat(display.getText().toString());
                    multiplication = true;
                    display.setText("");
                }
                break;
            case R.id.button_divide:
                if (display.getText().length() != 0) {
                    num1 = Float.parseFloat(display.getText().toString());
                    division = true;
                    display.setText("");
                }
                break;
            case R.id.button_equal:
                if (display.getText().length() != 0) {
                    num2 = Float.parseFloat(display.getText().toString());
                    if (addition) {
                        display.setText(String.valueOf(num1 + num2));
                        addition = false;
                    } else if (subtraction) {
                        display.setText(String.valueOf(num1 - num2));
                        subtraction = false;
                    } else if (multiplication) {
                        display.setText(String.valueOf(num1 * num2));
                        multiplication = false;
                    } else if (division) {
                        display.setText(String.valueOf(num1 / num2));
                        division = false;
                    }
                }
                break;
            case R.id.button_clear:
                display.setText("");
                num1 = 0;
                num2 = 0;
                addition = false;
                subtraction = false;
                multiplication = false;
                division = false;
                break;
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:tools="http://schemas.android.com/tools"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical"
              android:padding="16dp"
              tools:context=".MainActivity">

    <TextView
            android:id="@+id/display"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="16dp"
            android:background="@drawable/edit_text_background"
            android:gravity="end"
            android:padding="16dp"
            android:textSize="24sp"/>

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

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

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

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

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

    <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="16dp"
            android:orientation="horizontal"
            android:weightSum="4">

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

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

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

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

    <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="16dp"
            android:orientation="horizontal"
            android:weightSum="4">

        <Button
                android:id="@+id/button_one"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="1"/>

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

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

        <Button
                android:id="@+id/button_subtract"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="-"/>
    </LinearLayout>

    <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="16dp"
            android:orientation="horizontal"
            android:weightSum="4">

        <Button
                android:id="@+id/button_zero"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="0"/>

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

        <Button
                android:id="@+id/button_equal"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="="/>

        <Button
                android:id="@+id/button_add"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="+"/>
    </LinearLayout>

</LinearLayout>

这个计算器实现了加、减、乘、除四种基本运算，以及清空和等于两个功能。用户可以通过点击数字按钮输入数字，通过点击运算按钮进行相应的运算，最终结果会显示在文本框中。