Add MainActivity

.idea/gradle.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="GradleMigrationSettings" migrationVersion="1" />
   <component name="GradleSettings">
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>

app/build.gradle

@@ -24,6 +24,7 @@ android {
 dependencies {
     implementation fileTree(dir: "libs", include: ["*.jar"])
     implementation 'androidx.appcompat:appcompat:1.2.0'
+    implementation 'androidx.constraintlayout:constraintlayout:2.0.1'
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test.ext:junit:1.1.2'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'

app/src/main/AndroidManifest.xml

@@ -1,3 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="de.hems.trafficsim">
 
@@ -7,6 +8,13 @@
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
-        android:theme="@style/AppTheme" />
+        android:theme="@style/AppTheme">
+        <activity android:name=".MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
 
 </manifest>

app/src/main/java/de/hems/trafficsim/MainActivity.java

@@ -0,0 +1,14 @@
+package de.hems.trafficsim;
+
+import androidx.appcompat.app.AppCompatActivity;
+
+import android.os.Bundle;
+
+public class MainActivity extends AppCompatActivity {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+    }
+}

app/src/main/res/layout/activity_main.xml

@@ -0,0 +1,9 @@
+<?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">
+
+</androidx.constraintlayout.widget.ConstraintLayout>