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

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?

Solution 1:

Go to File > Sync Project with Gradles Files.

Solution 2:

Quit the Android Studio ( not close the project Quit the Android Studio) then open the project and go to Android Studio > Build > Clean Project

Then Android Studio > File > Sync Project with Gradles Files as the pic below

If your problem still exists then click the Install build tool as the pic below and then Android Studio > File > Sync Project with Gradles Files