# ConstraintLayout's Barrier important note
[SOURCE](https://constraintlayout.com/basics/barriers.html)
```xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:text="@string/warehouse"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:text="@string/hospital"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView1" />
<android.support.constraint.Barrier
android:id="@+id/barrier7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:barrierDirection="end"
app:constraint_referenced_ids="textView2,textView1" />
<!--This is the most important factor, the TextView that need to constraint to a Barrier-->
<!--need to have its width or height set to match_constraint instead of wrap_content-->
<TextView
android:id="@+id/textView3"
android:layout_width="0dp" <---- IMPORTANT
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:text="@string/lorem_ipsum"
app:layout_constraintStart_toEndOf="@+id/barrier7"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
```