Come fare in modo che gli oggetti nel layout siano disposti a cerchio?

Per disporre gli oggetti in cerchio, puoi usare ConstraintLayout con Circular positioning.

<androidx.constraintlayout.widget.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/center_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Centro"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Bottone 1"
        app:layout_constraintCircle="@+id/center_view" // ID dell'elemento centrale
        app:layout_constraintCircleRadius="150dp" // Raggio del cerchio
        app:layout_constraintCircleAngle="0" /> // Angolo in gradi (0° - a destra)

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Bottone 2"
        app:layout_constraintCircle="@+id/center_view"
        app:layout_constraintCircleRadius="150dp"
        app:layout_constraintCircleAngle="90" /> // 90° - sotto

    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Bottone 3"
        app:layout_constraintCircle="@+id/center_view"
        app:layout_constraintCircleRadius="150dp"
        app:layout_constraintCircleAngle="180" /> // 180° - a sinistra

    <Button
        android:id="@+id/button4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Bottone 4"
        app:layout_constraintCircle="@+id/center_view"
        app:layout_constraintCircleRadius="150dp"
        app:layout_constraintCircleAngle="270" /> // 270° - sopra

</androidx.constraintlayout.widget.ConstraintLayout>

Attributi per il posizionamento circolare:

Attributo	Descrizione
app:layout_constraintCircle	ID dell'elemento attorno al quale si costruisce il cerchio.
app:layout_constraintCircleRadius	Raggio del cerchio in dp.
app:layout_constraintCircleAngle	Angolo in gradi (0° - a destra del centro, aumenta in senso antiorario).