How can I fix "Design editor is unavailable until a successful build" error?

Question

I started to learn Android Studio. I try to echo out simple "Hello World":

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout     android:id="@+id/activity_main"     xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:paddingLeft="16dp"     android:paddingRight="16dp"     android:paddingTop="16dp"     android:paddingBottom="16dp"     tools:context=".MainActivity">      <TextView         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Hello World!" />  </RelativeLayout> 

but when I clicked "design" view, this error is showing?

Design editor is unavailable until a successful build

How can I fix this error.

I just noticed that my xml code is causing error. Is that why this may be not working?

Answer 1

Go to File > Sync Project with Gradles Files.