Tips and Tricks

Spacing

Be aware that many layouts have default spacing parameters. If things don't line up correctly you may have to remove this default spacing.

Be warned that much of the styling of Rock Mobile has been done with the default spacing in mind. If you disable it you may notice that many controls are closer than usual. When you disable spacing you may find yourself swimming upstream.

For example, StackLayouts have a default Spacing property set to 10. This means each control within the layout will have a 10-unit space between it and its neighbor. For a StackLayout, the spacing will be relative to its Orientation property. When set to Horizontal it will be horizontal spacing, Vertical would be vertical spacing.

Other layout controls also have this same behavior. Below is a list of others (this is not meant to be an inclusive list).

• Grid - Has default RowSpacing and ColumnSpacing values

• ResponsiveLayout - Has a default ColumnSpacing value

• Frame - Has a default Padding of 10

Device Type Customization

As you assign values to properties you may want to have different values for a phone vs. a tablet. This is often the case when working with the sizes of images and cards (via the Ratio properties). Providing different properties is possible using the syntax below.

<Label Text="{Rock:OnDeviceType Phone='I am a phone!', Tablet='I am a tablet!'}" 
    Margin="{Rock:OnDeviceType Phone='20, 20, 20, 20', Tablet='0, 0, 0, 0' }" />

<Image Source="https://yourserver.com/photo.jpg" 
    Ratio="{Rock:OnDeviceType Phone=4:3, Tablet=4:2}" />

If you'd like to change more than just a property, and instead provide different markup, you can use the controls below.

 <Rock:OnDeviceType>
    <Rock:OnDeviceType.Phone>
        <BoxView Color="Red" HeightRequest="10" />
    </Rock:OnDeviceType.Phone>
    <Rock:OnDeviceType.Tablet>
        <BoxView Color="Blue" HeightRequest="10" />
    </Rock:OnDeviceType.Tablet>
</Rock:OnDeviceType>

StringFormat Data Binding

From time to time, you’ll find yourself needing to Bind data as part of a string. You may be tempted to just throw your Binding in the middle of the string as you would in Lava, but you’ll be disappointed as nothing will show up. This is where StringFormat comes into play.

<Label Text="{Binding Name, StringFormat='Hey there {0}!'}" />

In this case, the Key we are Binding to is Name and we want it to output “Hey there Ted!”. We use {0} to insert our Binding Value into the string where we want it to show up.

YouVersion Bible App Links

The YouVersion Bible app provides deep linking for many of the resource types they have available. We won't cover the full breadth of options here, but this will get you started. If someone has the Bible app installed, these resources will be opened natively in the app, falling back to the external browser experience if necessary.

For the most part, any URL you provide from the bible.com website will work. We recommend using that as a reference to ensure your URL is valid and to always test once you've added it to the app.

Here's a button snippet you can copy for quick additions to your app:

<Button Text="Bible App"
    StyleClass="btn, btn-primary"
    Command="{Binding OpenExternalBrowser}"
    CommandParameter="https://www.bible.com/" />

Bible Reference

Passage references include a version ID in the route (59 is for ESV) followed by a three-letter book identifier. Be very careful to provide valid values, especially for the version number! You may notice slugs in some of the URLs provided by the website, but they're typically unnecessary.

Type	URL Pattern
Book	https://www.bible.com/bible/59/GEN.1
Verse	https://www.bible.com/bible/59/GEN.1.1
Multi-verse	https://www.bible.com/bible/59/GEN.1.1-4
Reading Plan	https://www.bible.com/reading-plans/16169
Video	https://www.bible.com/videos/25490
Podcast Episode	https://www.bible.com/podcasts/395/episodes/59548

Push Notification State

You may want to determine on a page if Push Notifications are enabled and ready for use so that you can prompt the user to enable them. For example, if you have a page that lets the user sign up to receive push notifications about an upcoming event, you might want to make sure notifications are enabled - or at least tell the user they have disabled them. We provide two values in your AppValues model to detect these states.

• core_PushNotificationHasBeenRequested - This will be a True boolean value if the user has ever been prompted to enable push notifications. Otherwise, it will be False.

• core_NotificationsAreEnabled - This will be a True boolean value if notifications are determined to be enabled on the device. Otherwise, it will be False.

In the example below, we are manually building an if-else block by making use of the IsVisible properties. The first StackLayout will be shown if the user has never been asked to enable push notifications. The second StackLayout will be shown if the user has been asked but either denied or disabled notifications. The third and final StackLayout will be shown if they have been both asked and have notifications enabled.

Additionally, the first block will let them click a button to enable notifications. The second block has a button they can click to go to Settings and turn notifications back on.

You might wonder why we are doing it this way even though the AppValues are accessible via Lava. The reason to use bindings like this is so the UI is reactive. Suppose they have manually turned off notifications. The second block will show prompting them to go to settings and re-enable them. The user clicks the button, goes to settings and turns notifications back on, and then returns to the application. As soon as the app loads it will update the AppValues which will trigger the Binding to update and hide the second block and show the third block instead. All without having to actually reload the page.

Example

<!-- if -->
<StackLayout IsVisible="{Binding AppValues.core_PushNotificationHasBeenRequested, Converter={Rock:InverseBooleanConverter}}">
    <Label Text="Would you like to enable push notifications?" />
    <Button StyleClass="btn,btn-primary"
        Text="Enable Notification"
        Command="{Binding EnablePushNotifications}" />
</StackLayout>

<!-- elseif -->
<StackLayout IsVisible="{Binding AppValues.core_PushNotificationHasBeenRequested}">
    <StackLayout IsVisible="{Binding AppValues.core_NotificationsAreEnabled, Converter={Rock:InverseBooleanConverter}}">
        <Label Text="Your notifications are disabled, would you like to fix that?" />
        <Button StyleClass="btn,btn-primary"
            Text="Settings"
            Command="{Binding OpenAppSettings}" />
    </StackLayout>

    <!-- else -->
    <StackLayout IsVisible="{Binding AppValues.core_NotificationsAreEnabled}">
        <Label Text="You'll be hearing from us." />
    </StackLayout>
</StackLayout>