只实现了界面，没有实现具体功能

通过<Button />,<EditText />控件实现，采用<GridLayout />网格布局实现界面布局

效果图：

activity_main.xml中代码

<?xml version="1.0" encoding="utf-8"?>
<GridLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:rowCount="7"
    android:columnCount="4">

    <EditText
        android:hint="请输入"
        android:gravity="bottom"
        android:layout_height="100sp"
        android:textSize="50sp"
        android:layout_rowWeight="2"
        android:layout_columnWeight="4"
        android:layout_rowSpan="2"
        android:layout_columnSpan="4"
        android:layout_gravity="fill"
        />

    <Button
        android:text="清除"
        android:layout_height="40sp"
        android:textSize="30sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="4"
        android:layout_rowSpan="1"
        android:layout_columnSpan="4"
        android:layout_gravity="fill" />

    <Button
        android:text="7"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
       />

    <Button
        android:text="8"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
        />

    <Button
        android:text="9"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
       />

    <Button
        android:text="÷"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
       />

    <Button
        android:text="4"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
        />

    <Button
        android:text="5"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
        />

    <Button
        android:text="6"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
       />

    <Button
        android:text="*"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
        />

    <Button
        android:text="1"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
        />

    <Button
        android:text="2"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
      />

    <Button
        android:text="3"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
      />

    <Button
        android:text="-"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
        />

    <Button
        android:text="."
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
       />

    <Button
        android:text="0"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
        />

    <Button
        android:text="+"
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
       />

    <Button
        android:text="="
        android:textSize="50sp"
        android:layout_rowWeight="1"
        android:layout_columnWeight="1"
        />
</GridLayout>

 改软件名称

res——>values——>strings.xml文件中

<resources>
    <string name="app_name">计算器</string>
</resources>