Android Studio 计算器代码

以下是一个简单的 Android Studio 计算器代码：

XML 布局文件：

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp">

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="24sp"
        android:gravity="right"
        android:padding="8dp"
        android:text="0" />

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

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

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

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

        <Button
            android:id="@+id/buttonDivide"
            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:orientation="horizontal">

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

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

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

        <Button
            android:id="@+id/buttonMultiply"
            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:orientation="horizontal">

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

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

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

        <Button
            android:id="@+id/buttonMinus"
            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:orientation="horizontal">

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

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

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

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

    </LinearLayout>

    <Button
        android:id="@+id/buttonClear"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Clear" />

</LinearLayout>

Java 代码：

public class MainActivity extends AppCompatActivity {

    private TextView textView;
    private String currentNumber = "0";
    private String currentOperator = "";
    private boolean operatorClicked = false;

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

        textView = findViewById(R.id.textView);

        Button button0 = findViewById(R.id.button0);
        button0.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("0");
            }
        });

        Button button1 = findViewById(R.id.button1);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("1");
            }
        });

        Button button2 = findViewById(R.id.button2);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("2");
            }
        });

        Button button3 = findViewById(R.id.button3);
        button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("3");
            }
        });

        Button button4 = findViewById(R.id.button4);
        button4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("4");
            }
        });

        Button button5 = findViewById(R.id.button5);
        button5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("5");
            }
        });

        Button button6 = findViewById(R.id.button6);
        button6.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("6");
            }
        });

        Button button7 = findViewById(R.id.button7);
        button7.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("7");
            }
        });

        Button button8 = findViewById(R.id.button8);
        button8.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("8");
            }
        });

        Button button9 = findViewById(R.id.button9);
        button9.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                numberClicked("9");
            }
        });

        Button buttonDot = findViewById(R.id.buttonDot);
        buttonDot.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!currentNumber.contains(".")) {
                    currentNumber += ".";
                    textView.setText(currentNumber);
                }
            }
        });

        Button buttonPlus = findViewById(R.id.buttonPlus);
        buttonPlus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                operatorClicked("+");
            }
        });

        Button buttonMinus = findViewById(R.id.buttonMinus);
        buttonMinus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                operatorClicked("-");
            }
        });

        Button buttonMultiply = findViewById(R.id.buttonMultiply);
        buttonMultiply.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                operatorClicked("*");
            }
        });

        Button buttonDivide = findViewById(R.id.buttonDivide);
        buttonDivide.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                operatorClicked("/");
            }
        });

        Button buttonEquals = findViewById(R.id.buttonEquals);
        buttonEquals.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!operatorClicked) {
                    return;
                }

                double result = 0;

                switch (currentOperator) {
                    case "+":
                        result = Double.parseDouble(currentNumber) + Double.parseDouble(textView.getText().toString());
                        break;
                    case "-":
                        result = Double.parseDouble(currentNumber) - Double.parseDouble(textView.getText().toString());
                        break;
                    case "*":
                        result = Double.parseDouble(currentNumber) * Double.parseDouble(textView.getText().toString());
                        break;
                    case "/":
                        result = Double.parseDouble(currentNumber) / Double.parseDouble(textView.getText().toString());
                        break;
                }

                currentNumber = String.valueOf(result);
                textView.setText(currentNumber);
                operatorClicked = false;
            }
        });

        Button buttonClear = findViewById(R.id.buttonClear);
        buttonClear.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                currentNumber = "0";
                currentOperator = "";
                operatorClicked = false;
                textView.setText(currentNumber);
            }
        });
    }

    private void numberClicked(String number) {
        if (currentNumber.equals("0")) {
            currentNumber = number;
        } else {
            currentNumber += number;
        }

        textView.setText(currentNumber);
        operatorClicked = true;
    }

    private void operatorClicked(String operator) {
        if (!operatorClicked) {
            currentOperator = operator;
            operatorClicked = true;
        } else {
            double result = 0;

            switch (currentOperator) {
                case "+":
                    result = Double.parseDouble(currentNumber) + Double.parseDouble(textView.getText().toString());
                    break;
                case "-":
                    result = Double.parseDouble(currentNumber) - Double.parseDouble(textView.getText().toString());
                    break;
                case "*":
                    result = Double.parseDouble(currentNumber) * Double.parseDouble(textView.getText().toString());
                    break;
                case "/":
                    result = Double.parseDouble(currentNumber) / Double.parseDouble(textView.getText().toString());
                    break;
            }

            currentNumber = String.valueOf(result);
            textView.setText(currentNumber);
            currentOperator = operator;
        }
    }
}