用Android studio写一个简单运算的页面设计与代码

好的，以下是一个简单的 Android Studio 代码示例，实现了一个简单的四则运算器的页面设计和代码：

XML布局文件：

<RelativeLayout 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"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/firstNumEditText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:hint="First Number"
        android:gravity="center"
        android:inputType="number" />

    <EditText
        android:id="@+id/secondNumEditText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/firstNumEditText"
        android:hint="Second Number"
        android:gravity="center"
        android:inputType="number" />

    <RadioButton
        android:id="@+id/addRadioButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/secondNumEditText"
        android:checked="true"
        android:text="Add" />

    <RadioButton
        android:id="@+id/subtractRadioButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/addRadioButton"
        android:text="Subtract" />

    <RadioButton
        android:id="@+id/multiplyRadioButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/subtractRadioButton"
        android:text="Multiply" />

    <RadioButton
        android:id="@+id/divideRadioButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/multiplyRadioButton"
        android:text="Divide" />

    <Button
        android:id="@+id/calculateButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/divideRadioButton"
        android:text="Calculate" />

    <TextView
        android:id="@+id/resultTextView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/calculateButton"
        android:gravity="center"
        android:paddingTop="50dp"
        android:text="Result" />

</RelativeLayout>

Java代码：

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private EditText firstNumEditText, secondNumEditText;
    private RadioButton addRadioButton, subtractRadioButton, multiplyRadioButton, divideRadioButton;
    private Button calculateButton;
    private TextView resultTextView;

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

        firstNumEditText = findViewById(R.id.firstNumEditText);
        secondNumEditText = findViewById(R.id.secondNumEditText);
        addRadioButton = findViewById(R.id.addRadioButton);
        subtractRadioButton = findViewById(R.id.subtractRadioButton);
        multiplyRadioButton = findViewById(R.id.multiplyRadioButton);
        divideRadioButton = findViewById(R.id.divideRadioButton);
        calculateButton = findViewById(R.id.calculateButton);
        resultTextView = findViewById(R.id.resultTextView);

        calculateButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                double firstNum = Double.parseDouble(firstNumEditText.getText().toString());
                double secondNum = Double.parseDouble(secondNumEditText.getText().toString());
                double result;

                if (addRadioButton.isChecked()) {
                    result = firstNum + secondNum;
                    resultTextView.setText(String.format("%.2f", result));
                } else if (subtractRadioButton.isChecked()) {
                    result = firstNum - secondNum;
                    resultTextView.setText(String.format("%.2f", result));
                } else if (multiplyRadioButton.isChecked()) {
                    result = firstNum * secondNum;
                    resultTextView.setText(String.format("%.2f", result));
                } else if (divideRadioButton.isChecked()) {
                    if (secondNum == 0) {
                        Toast.makeText(MainActivity.this, "Cannot divide by zero", Toast.LENGTH_LONG).show();
                    } else {
                        result = firstNum / secondNum;
                        resultTextView.setText(String.format("%.2f", result));
                    }
                }
            }
        });

    }
}

希望这个例子能对你有所帮助！