android简易计算器

以下是一个简单的 Android 计算器示例代码：

activity_main.xml:

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

    <EditText
        android:id="@+id/display"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="0"
        android:inputType="none"
        android:textSize="30sp" />

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

        <Button
            android:id="@+id/button_7"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="7"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_8"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="8"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_9"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="9"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_divide"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="/"
            android:textSize="20sp" />
    </LinearLayout>

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

        <Button
            android:id="@+id/button_4"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="4"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_5"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="5"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_6"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="6"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_multiply"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="*"
            android:textSize="20sp" />
    </LinearLayout>

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

        <Button
            android:id="@+id/button_1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="1"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_2"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="2"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_3"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="3"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_minus"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="-"
            android:textSize="20sp" />
    </LinearLayout>

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

        <Button
            android:id="@+id/button_0"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="0"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_dot"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="."
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_clear"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="C"
            android:textSize="20sp" />

        <Button
            android:id="@+id/button_plus"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="+"
            android:textSize="20sp" />
    </LinearLayout>

    <Button
        android:id="@+id/button_equals"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="="
        android:textSize="20sp" />

</LinearLayout>

MainActivity.java:

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

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    EditText display;
    Button button_0, button_1, button_2, button_3, button_4, button_5, button_6, button_7, button_8, button_9, button_dot, button_clear, button_divide, button_multiply, button_minus, button_plus, button_equals;

    float mValueOne, mValueTwo;

    boolean mAddition, mSubtract, mMultiplication, mDivision;

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

        display = findViewById(R.id.display);

        button_0 = findViewById(R.id.button_0);
        button_1 = findViewById(R.id.button_1);
        button_2 = findViewById(R.id.button_2);
        button_3 = findViewById(R.id.button_3);
        button_4 = findViewById(R.id.button_4);
        button_5 = findViewById(R.id.button_5);
        button_6 = findViewById(R.id.button_6);
        button_7 = findViewById(R.id.button_7);
        button_8 = findViewById(R.id.button_8);
        button_9 = findViewById(R.id.button_9);
        button_dot = findViewById(R.id.button_dot);
        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_0.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "0");
            }
        });

        button_1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "1");
            }
        });

        button_2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "2");
            }
        });

        button_3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "3");
            }
        });

        button_4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "4");
            }
        });

        button_5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "5");
            }
        });

        button_6.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "6");
            }
        });

        button_7.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "7");
            }
        });

        button_8.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "8");
            }
        });

        button_9.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + "9");
            }
        });

        button_dot.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.setText(display.getText() + ".");
            }
        });

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

        button_plus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (display == null) {
                    display.setText("");
                } else {
                    mValueOne = Float.parseFloat(display.getText() + "");
                    mAddition = true;
                    display.setText(null);
                }
            }
        });

        button_minus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mValueOne = Float.parseFloat(display.getText() + "");
                mSubtract = true;
                display.setText(null);
            }
        });

        button_multiply.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mValueOne = Float.parseFloat(display.getText() + "");
                mMultiplication = true;
                display.setText(null);
            }
        });

        button_divide.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mValueOne = Float.parseFloat(display.getText() + "");
                mDivision = true;
                display.setText(null);
            }
        });

        button_equals.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mValueTwo = Float.parseFloat(display.getText() + "");

                if (mAddition) {
                    display.setText(mValueOne + mValueTwo + "");
                    mAddition = false;
                }

                if (mSubtract) {
                    display.setText(mValueOne - mValueTwo + "");
                    mSubtract = false;
                }

                if (mMultiplication) {
                    display.setText(mValueOne * mValueTwo + "");
                    mMultiplication = false;
                }

                if (mDivision) {
                    display.setText(mValueOne / mValueTwo + "");
                    mDivision = false;
                }
            }
        });
    }
}

运行后，您将看到一个简单的计算器应用程序。