ADD file via upload

activity_main.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".MainActivity">
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:orientation="vertical">
+        <TextView
+            android:layout_width="match_parent"
+            android:layout_height="50dp"
+            android:gravity="center"
+            android:singleLine="true"
+            android:text="欢迎您"
+            tools:layout_editor_absoluteX="49dp"
+            tools:layout_editor_absoluteY="53dp" />
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:orientation="horizontal"
+            >
+            <Button
+                android:id="@+id/student_button"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:text="我是学生"/>
+
+            <Button
+                android:id="@+id/teacher_button"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginStart="10dp"
+                android:layout_weight="1"
+                android:text="我是老师" />
+        </LinearLayout>
+    </LinearLayout>
+
+
+</androidx.constraintlayout.widget.ConstraintLayout>