Android Code Snippet Custom notifications (including expandable ones), with JavaObject and XML layout

Since the NotificationBuilder library is deprecated and NB6 doesn't support custom or extended notifications, I developed this example using AI, the JavaObject library, and native Android/AndroidX components.

Although the notification takes a few seconds to create the first time.

Creating the XML Layout

The unique XML layout in this example was created from a design created with the B4A visual designer:

1. I designed the layout in B4A
2. I took a screenshot
3. I uploaded it to the AI to create the corresponding XML (after several corrective iterations)

Alternative: It can also be created and exported as XML from Android Studio, although this requires configuring a separate Android SDK (Do not share it with the Android SDK used by B4A to avoid conflicts)

File Configuration

Layout XML

• Path: JavaObjectNotification\B4A\Objects\res\layout
• Important: Set the file to Read-only to prevent it from being deleted during compilation.

ImageView Icons

• Path: JavaObjectNotification\B4A\Objects\res\
• Structure: Different folders inside depending on size of PNG files (drawable-mdpi, drawable-hdpi, etc.)
• Note: RemoteViews do NOT have access to the Assets folder, so they must be located in res.

Files in drawable (optional)

• Path: JavaObjectNotification\B4A\Objects\res\drawable
• Use: To modify the shapes of layout elements.
• Important: Also set to Read-only.
• Names: circle.xml, rounded.xml and rounded_background.xml
• Warning: These additional XML files are not included in the project and may require adjustments

Implemented Features

Intent to open the application when clicking on the notification background
- The example allows you to enable or disable this feature. NB6 does not allow disabling it.
- Elements without a PendingIntent are also considered background elements.

Action Management:
ImageView or Label actions are sent via Intent to the B4A Receiver, which then forwards them to the service.

Optional Feature

Expanded and Collapsed Layouts

- Two different layouts could be used (not implemented in this example)
- The system automatically selects which one to use based on the state

Dim rvCustom As JavaObject = CreateRemoteViews("notif_custom_layout")
Dim rvCustomBig As JavaObject = CreateRemoteViews("notif_custom_big_layout")

builder.RunMethod("setCustomContentView", Array(rvCustom)) 'Max height = ~64dp
builder.RunMethod("setCustomBigContentView", Array(rvCustomBig)) 'Max height = ~256dp

Design Considerations:

- When designing the layout, verify which elements are hidden when collapsed.
- The background color could be set to almost transparent by default in the XML ("#10000000") to adapt to the system's Light and Dark modes.

Notification Interaction

- Actions of ImageViews or Labels when clicked
- Open the application when clicking on the notification background, or not (depending on the programming)
- Expand/collapse: Click on the upper right arrow (managed by the system)

Note:

• This is a basic, functional example that can be extended or modified according to specific needs
• I added the FOREGROUND_SERVICE_DATA_SYNC permission in the Manifest Editor to test it, but you can also add the FOREGROUND_SERVICE_SPECIAL_USE permission with its respective complementary lines.
• I had to remove the Objects folder to upload the project zip file. Compile once to recreate the Objects folder and replace the "res" folder inside with the contents of res.zip