simplefileupload-android/app/src/main/res/layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <TextView
        android:id="@+id/headerText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/app_header"
        android:textSize="24sp"
        android:textStyle="bold"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        android:layout_marginTop="16dp"/>

    <!-- Main Upload Options Section -->
    <androidx.cardview.widget.CardView
        android:id="@+id/uploadOptionsCard"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        app:cardCornerRadius="8dp"
        app:cardElevation="4dp"
        app:layout_constraintTop_toBottomOf="@id/headerText">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:padding="16dp">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/upload_options_title"
                android:textSize="18sp"
                android:textStyle="bold"/>

            <Button
                android:id="@+id/selectFileButton"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:text="@string/select_file_button"
                android:drawableStart="@android:drawable/ic_menu_search"
                android:paddingStart="16dp"
                android:paddingEnd="16dp"/>

            <Button
                android:id="@+id/uploadDumpstateButton"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="8dp"
                android:text="@string/upload_dumpstate_button"
                android:drawableStart="@android:drawable/ic_menu_save"
                android:paddingStart="16dp"
                android:paddingEnd="16dp"/>
        </LinearLayout>
    </androidx.cardview.widget.CardView>

    <!-- Dumpstate Section -->
    <androidx.cardview.widget.CardView
        android:id="@+id/dumpstateCard"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        app:cardCornerRadius="8dp"
        app:cardElevation="4dp"
        app:layout_constraintTop_toBottomOf="@id/uploadOptionsCard">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:padding="16dp">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/dumpstate_section_title"
                android:textSize="18sp"
                android:textStyle="bold"/>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:layout_marginTop="4dp">
                
                <TextView
                    android:id="@+id/dumpstateStatusText"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:text="@string/looking_for_dumpstate"
                    android:textSize="16sp"
                    android:maxLines="3"
                    android:ellipsize="start"/>
                    
                <Button
                    android:id="@+id/toggleDumpstateListButton"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/show_dumpstates"
                    android:textSize="12sp"
                    style="@style/Widget.AppCompat.Button.Small" />
            </LinearLayout>
            
            <androidx.recyclerview.widget.RecyclerView
                android:id="@+id/dumpstateRecyclerView"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="8dp"
                android:visibility="gone"/>
                
            <LinearLayout
                android:id="@+id/multiSelectButtonsLayout"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:layout_marginTop="8dp"
                android:visibility="gone">
                
                <Button
                    android:id="@+id/selectAllButton"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:text="@string/select_all"
                    android:textSize="12sp"
                    style="@style/Widget.AppCompat.Button.Borderless.Colored" />
                    
                <Button
                    android:id="@+id/clearSelectionsButton"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:text="@string/clear_selections"
                    android:textSize="12sp"
                    style="@style/Widget.AppCompat.Button.Borderless.Colored" />
            </LinearLayout>
        </LinearLayout>
    </androidx.cardview.widget.CardView>

    <!-- Selected File Section -->
    <androidx.cardview.widget.CardView
        android:id="@+id/selectedFileCard"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        app:cardCornerRadius="8dp"
        app:cardElevation="4dp"
        android:visibility="gone"
        app:layout_constraintTop_toBottomOf="@id/dumpstateCard">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:padding="16dp">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/selected_file_section_title"
                android:textSize="18sp"
                android:textStyle="bold"/>

            <TextView
                android:id="@+id/selectedFileText"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="8dp"
                android:text="@string/no_file_selected"
                android:textSize="16sp"/>

            <Button
                android:id="@+id/uploadSelectedFileButton"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:text="@string/upload_selected_file"
                android:visibility="gone"/>
        </LinearLayout>
    </androidx.cardview.widget.CardView>

    <ProgressBar
        android:id="@+id/progressBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone"
        app:layout_constraintTop_toBottomOf="@id/selectedFileCard"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        android:layout_marginTop="16dp"/>

</androidx.constraintlayout.widget.ConstraintLayout>