How to remove the extra space outside the border?

Hope all of you are doing well!

I was making a custom dialog box and created a xml file named find_teacher_dialog.xml but it is not coming up exactly as I want.

Below is my xml code block which I tried:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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">

    <LinearLayout
        android:id="@+id/customDialogLL"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="16dp"
        android:layout_marginBottom="8dp"
        android:background="@drawable/dialog_bg"
        android:elevation="8dp"
        android:orientation="vertical"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <ImageView
            android:id="@+id/dialogImage"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_marginTop="16dp"
            android:contentDescription="@string/coming_soon_image"
            android:src="@drawable/coming_soon" />

        <Button
            android:id="@+id/okayBtn"
            android:layout_width="150dp"
            android:layout_height="55dp"
            android:layout_gravity="center"
            android:layout_marginTop="16dp"
            android:layout_marginBottom="16dp"
            android:background="@drawable/transparent_button_bg"
            android:elevation="5dp"
            android:fontFamily="sans-serif-condensed-medium"
            android:text="@string/okay"
            android:textColor="@color/black"
            android:textSize="24sp"
            android:textStyle="bold" />

    </LinearLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

The resultant screenshot is below:

Screenshot of the result

Help me with the resolution!

Thank you in advance!

I tried creating a custom dialog box with transparent background and a border but the result is showing the extra white space around the border.

##UPDATE##

Tried the answer by @heX and was able to remove the extra white spaces but still the corner are visible as white.

Below is the updated code:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/customDialogLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/dialog_bg"
    android:elevation="8dp">

    <ImageView
        android:id="@+id/dialogImage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="16dp"
        android:contentDescription="@string/coming_soon_image"
        android:src="@drawable/coming_soon"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/okayBtn"
        android:layout_width="150dp"
        android:layout_height="55dp"
        android:layout_gravity="center"
        android:layout_marginTop="16dp"
        android:layout_marginBottom="16dp"
        android:background="@drawable/transparent_button_bg"
        android:elevation="5dp"
        android:fontFamily="sans-serif-condensed-medium"
        android:text="@string/okay"
        android:textColor="@color/black"
        android:textSize="24sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="@id/dialogImage"
        app:layout_constraintStart_toStartOf="@id/dialogImage"
        app:layout_constraintTop_toBottomOf="@id/dialogImage" />


</androidx.constraintlayout.widget.ConstraintLayout>

Solution

The problem you have is that you are adding a margin on the same ViewGroup that has the background. The top level ConstraintLayout is the ViewGroup that should have the background, and then the contents can have margin/padding.

Now, I see that you have rounded corners so you have going to have to create a background like this one if you haven't already:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <corners android:radius="12dp"/>
    <stroke android:color="@android:color/black" android:width="4dp"/>
    <solid android:color="@android:color/transparent"/>
</shape>