学习进度笔记

 

 

<EditText
    android:id="@+id/editText"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:inputType="number" />

<Button
    android:id="@+id/buttonAdd"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="+" />

<Button
    android:id="@+id/buttonSubtract"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="-" />

<Button
    android:id="@+id/buttonMultiply"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="*" />

<Button
    android:id="@+id/buttonDivide"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="/" />

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

<TextView
    android:id="@+id/textViewResult"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="24sp" />

接下来，在MainActivity.java文件中，添加以下代码来处理按钮点击事件和计算逻辑：

javaCopy Code

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    private EditText editText;
    private Button buttonAdd;
    private Button buttonSubtract;
    private Button buttonMultiply;
    private Button buttonDivide;
    private Button buttonEquals;
    private TextView textViewResult;

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

        // 初始化视图
        editText = findViewById(R.id.editText);
        buttonAdd = findViewById(R.id.buttonAdd);
        buttonSubtract = findViewById(R.id.buttonSubtract);
        buttonMultiply = findViewById(R.id.buttonMultiply);
        buttonDivide = findViewById(R.id.buttonDivide);
        buttonEquals = findViewById(R.id.buttonEquals);
        textViewResult = findViewById(R.id.textViewResult);

        // 设置按钮点击事件
        buttonAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                calculate('+');
            }
        });

        buttonSubtract.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                calculate('-');
            }
        });

        buttonMultiply.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                calculate('*');
            }
        });

        buttonDivide.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                calculate('/');
            }
        });

        buttonEquals.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                calculate('=');
            }
        });
    }

    private void calculate(char operator) {
        String input = editText.getText().toString();
        String[] numbers = input.split("[+\\-*/=]");

        if (numbers.length != 2) {
            textViewResult.setText("Invalid input");
            return;
        }

        double num1 = Double.parseDouble(numbers[0]);
        double num2 = Double.parseDouble(numbers[1]);
        double result = 0;

        switch (operator) {
            case '+':
                result = num1 + num2;
                break;
            case '-':
                result = num1 - num2;
                break;
            case '*':
                result = num1 * num2;
                break;
            case '/':
                if (num2 != 0) {
                    result = num1 / num2;
                } else {
                    textViewResult.setText("Cannot divide by zero");
                    return;
                }
                break;
        }

        textViewResult.setText(String.valueOf(result));
    }
}