update gradle

app/build.gradle

 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 29
     buildToolsVersion "30.0.2"
 
     defaultConfig {
         applicationId "com.example.yourcashiertest"
         minSdkVersion 23
-        targetSdkVersion 30
+        targetSdkVersion 29
         versionCode 1
         versionName "1.0"
 
@@ -33,15 +33,25 @@ android {
 dependencies {
     implementation fileTree(dir: "libs", include: ["*.jar"])
     implementation 'androidx.appcompat:appcompat:1.2.0'
+    implementation 'com.google.android.material:material:1.2.0'
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
-    testImplementation 'junit:junit:4.12'
+
+    def room_version = "2.2.5"
+
+    implementation "androidx.room:room-runtime:$room_version"
+    annotationProcessor "androidx.room:room-compiler:$room_version"
+
+    def lifecycle_version = "2.2.0"
+
+    implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
+    implementation "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"
+
+    def glide_version = "4.11.0"
+
+    implementation "com.github.bumptech.glide:glide:$glide_version"
+    annotationProcessor "com.github.bumptech.glide:compiler:$glide_version"
+
+    testImplementation 'junit:junit:4.13'
     androidTestImplementation 'androidx.test.ext:junit:1.1.1'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
-    implementation "androidx.lifecycle:lifecycle-extensions:2.2.0"
-    implementation "androidx.lifecycle:lifecycle-common-java8:2.2.0"
-    implementation 'com.google.android.material:material:1.2.0'
-    implementation "com.github.bumptech.glide:glide:4.11.0"
-    annotationProcessor "com.github.bumptech.glide:compiler:4.11.0"
-    implementation "androidx.room:room-runtime:2.2.5"
-    annotationProcessor "androidx.room:room-compiler:2.2.5"
 }
\ No newline at end of file

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

@@ -80,6 +80,7 @@
         tools:layout_editor_absoluteX="9dp" />
 
     <include
+        android:id="@+id/include"
         layout="@layout/cart_item"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
@@ -88,5 +89,15 @@
         app:layout_constraintTop_toBottomOf="@+id/view"
         app:layout_constraintVertical_bias="0.071" />
 
+    <Button
+        android:id="@+id/button"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="@string/checkout"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/include"
+        app:layout_constraintVertical_bias="1.0"
+        tools:layout_editor_absoluteX="39dp" />
+
 
 </androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file

app/src/main/res/values/strings.xml

@@ -16,4 +16,5 @@
     <string name="cash">Cash</string>
     <string name="rp_500_000">Rp. 500.000</string>
     <string name="pay">Pay</string>
+    <string name="checkout">Checkout</string>
 </resources>
\ No newline at end of file