diff --git a/app/src/main/java/edu/temple/helloworld/MainActivity.kt b/app/src/main/java/edu/temple/helloworld/MainActivity.kt
index afedb6d..dab7613 100644
--- a/app/src/main/java/edu/temple/helloworld/MainActivity.kt
+++ b/app/src/main/java/edu/temple/helloworld/MainActivity.kt
@@ -17,12 +17,18 @@ class MainActivity : AppCompatActivity() {
 
         // Initialize with views defined in Layout - the first one is done for you
         displayTextView = findViewById(R.id.displayTextView)
+        var nameEditText = findViewById<EditText>(R.id.nameEditText)
+
 
-        
         findViewById<Button>(R.id.clickMeButton).setOnClickListener {
-            displayTextView.text = "Hello, ${findViewById<EditText>(R.id.nameEditText).text}"
+            if(nameEditText.text.toString().length < 1){
+                nameEditText.setError("Please input name")
+            }else {
+
+                displayTextView.text = "Hello, ${findViewById<EditText>(R.id.nameEditText).text}"
+            }
         }
 
 
     }
-}
\ No newline at end of file
+}
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index ed108fc..6076994 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -13,15 +13,19 @@
         android:gravity="center"
         android:text="Hello World!"
         android:textSize="24sp"
-        tools:layout_editor_absoluteY="53dp" />
+        app:layout_constraintBottom_toTopOf="@+id/nameEditText"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
 
     <Button
         android:id="@+id/clickMeButton"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="Click Me"
-        tools:layout_editor_absoluteX="154dp"
-        tools:layout_editor_absoluteY="340dp" />
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent" />
 
     <EditText
         android:id="@+id/nameEditText"
@@ -31,7 +35,9 @@
         android:hint="Enter your name"
         android:inputType="textPersonName"
         android:minHeight="48dp"
-        tools:layout_editor_absoluteX="101dp"
-        tools:layout_editor_absoluteY="240dp" />
+        app:layout_constraintBottom_toTopOf="@+id/clickMeButton"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
 
-</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
+</androidx.constraintlayout.widget.ConstraintLayout>