我尝试将这个按钮放在布局下方的中心，布局都被 Package 在FlexLayout中。我在MAUI.NET中使用XAML。

下面是该页面的代码：

<FlexLayout VerticalOptions="Center" HorizontalOptions="Center">
    <StackLayout>
        <CollectionView ItemsSource="{Binding tasks}">
            <CollectionView.ItemTemplate>
                <DataTemplate x:DataType="models:Task">
                    <VerticalStackLayout Margin="15">
                        <Entry Text="{Binding name}" IsReadOnly="True" />
                        <Entry Text="{Binding departmentsString}" IsReadOnly="True"/>
                        <HorizontalStackLayout>
                            <Entry Text="{Binding status}" IsReadOnly="True"/>
                            <Entry Text="{Binding deadline}" IsReadOnly="True" />
                            <Entry Text="{Binding author.fullName}" IsReadOnly="True"/>
                        </HorizontalStackLayout>
                        <Entry Text="{Binding description}" IsReadOnly="True" />
                    </VerticalStackLayout>
                </DataTemplate>
            </CollectionView.ItemTemplate>
        </CollectionView>
    </StackLayout>
    <VerticalStackLayout Margin="15">
        <Entry Placeholder="Name" x:Name="nameTxt"/>
        <Entry Placeholder="Department" x:Name="departTxt"/>
        <HorizontalStackLayout>
            <Entry Placeholder="status" x:Name="statusTxt"/>
            <Entry Placeholder="deadline" x:Name="deadlineTxt"/>
            <Entry Placeholder="Author" x:Name="authorTxt"/>
        </HorizontalStackLayout>
        <Entry Placeholder="Description" x:Name="descTxt"/>
    </VerticalStackLayout>
    <AbsoluteLayout HorizontalOptions="Center" >
        <ImageButton Aspect="AspectFill" x:Name="addBtn" Source="plus.png" BackgroundColor="Black" Clicked="addBtn_Clicked"/>
    </AbsoluteLayout>
</FlexLayout>

我还尝试过像这样制作 Package 按钮的绝对布局，但没有积极的结果：

<AbsoluteLayout HorizontalOptions="Center" VerticalOptions="End">
        <ImageButton Aspect="AspectFill" x:Name="addBtn" Source="plus.png" BackgroundColor="Black" Clicked="addBtn_Clicked"/>
    </AbsoluteLayout>

我该怎么办？