Что делать?
Вот Layout AlertDialog
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:elevation="4dp">
<ScrollView
android:id="@+id/scrollView2"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="@+id/name"
android:layout_width="333dp"
android:layout_height="50dp"
android:layout_marginStart="24dp"
android:layout_marginTop="40dp"
android:textColor="#000000"
android:textSize="20pt"
android:textStyle="bold" />
<TextView
android:id="@+id/description"
android:layout_width="333dp"
android:layout_height="172dp"
android:layout_marginStart="24dp"
android:layout_marginTop="20dp"
android:layout_marginEnd="13dp"
android:textSize="14pt" />
<Button
android:id="@+id/btnJoin"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="161dp"
android:layout_marginTop="86dp"
android:layout_marginEnd="162dp"
android:layout_marginBottom="272dp"
android:text="@string/joint" />
</LinearLayout>
</ScrollView>
<ImageButton
android:id="@+id/closeBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right|end"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:adjustViewBounds="true"
android:background="@drawable/ic_action_content_clear"
android:cropToPadding="false"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="@+id/scrollView2"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="@+id/scrollView2"
app:layout_constraintTop_toTopOf="@+id/scrollView2"
app:layout_constraintVertical_bias="0.011"
app:srcCompat="@drawable/ic_action_content_clear" />
</android.support.constraint.ConstraintLayout>