DialogFragment is expanding the XML to full screen?

Question

i've implemented a DialogFragment , but it comes out looking like this:

instead of this (from XML preview):

fragment's onViewCreated

val button = view.findViewById(R.id.button_register) as Button
button.setOnClickListener{
    Log.d(TAG, "Clicked")
    val dialog = SuccessDialog()
    dialog.show(fragmentManager, "success dialog")
}

SuccessDialog class

class SuccessDialog: DialogFragment() {
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val view = inflater.inflate(R.layout.dialog_success, container, false)
        val button: Button = view.findViewById(R.id.button_ok)
        button.setOnClickListener{
            dialog.dismiss()
        }
        return view
    }
}

dialog's 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"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="250dp"
    android:layout_height="200dp"
    android:background="@color/colorPrimaryDark"
    android:padding="5dp"
    android:layout_gravity="center">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="47dp"
        android:layout_height="46dp"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:srcCompat="@drawable/ic_check_mark_24dp"
        android:contentDescription="@string/checkmark" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:text="@string/success"
        android:textColor="@android:color/white"
        android:textSize="18sp"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView" />

    <TextView
        android:id="@+id/textView6"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:gravity="center"
        android:text="@string/thank_you"
        android:textColor="@android:color/white"
        android:textStyle="italic"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView3" />

    <Button
        android:id="@+id/button_ok"
        android:layout_width="86dp"
        android:layout_height="40dp"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginBottom="8dp"
        android:text="@string/ok"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView6" />
</android.support.constraint.ConstraintLayout>

Answer 1

 tools:...

is just for xml preview . So please use :

 app:srcCompat="..." 

instead of

 tools:srcCompat="..."

To change the dimensions use this in onCreateView of your SuccessDialog

 if (getDialog() != null && getDialog().getWindow() != null) {
        getDialog().getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        getDialog().getWindow().setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
 }