how to get that when the bytes is sent completed in maui?

Question

I am using .net maui and I am sending bytes using BLE. may the bytes is 5 bytes or 5000bytes.

and how to get when the bytes is send completed. ?

in ios I am using Peripheral.WriteValue and in android I am using Characteristic.SetValue

Answer 1

Hi @mc ,

Thanks for reaching out.

When sending bytes over BLE in .NET MAUI, the key is that both iOS and Android handle writes asynchronously, so calling WriteValue or SetValue doesn’t mean the bytes are fully sent yet. You need to use the platform callbacks that signal completion.

iOS:

Use CBCharacteristicWriteType.withResponse when writing. Then implement the delegate peripheral(_:didWriteValueFor:error:) to know when the write is done: https://developer.apple.com/documentation/corebluetooth/cbperipheraldelegate/peripheral(_:didwritevaluefor:error:)-4f5ea

Android:

Set the value with characteristic.setValue(...), then call gatt.writeCharacteristic(characteristic). Handle completion in BluetoothGattCallback.onCharacteristicWrite(...), which is called when the write finishes: https://developer.android.com/reference/android/bluetooth/BluetoothGattCallback#onCharacteristicWrite(android.bluetooth.BluetoothGatt,%20android.bluetooth.BluetoothGattCharacteristic,%20int)

Basically, withResponse / default write type = callback that tells you it’s done. Without a response, there’s no confirmation.

A couple of extra tips:

• BLE often limits how many bytes you can send in a single write, so large byte arrays may need to be split into chunks.
• Writes withoutResponse will never trigger a callback, so completion confirmation is only possible with withResponse (iOS) or the default write type (Android).

Disclaimer: The links above are not from Microsoft but it's official links from Apple and Google.

Hope this helps! If my answer was helpful - kindly follow the instructions here so others with the same problem can benefit as well.

Answer 2

For IOS you should be using the peripheral(_:didWriteValueFor:error:) with characteristic CBCharacteristicWriteType.withResponse:

https://developer.apple.com/documentation/corebluetooth/cbperipheraldelegate/peripheral(_:didwritevaluefor:error:)-4f5ea

Answer 3

In .NET MAUI, to determine when the bytes have been sent completely during a Bluetooth Low Energy (BLE) operation, you typically rely on the event or callback mechanisms provided by the BLE library you are using. While the specific implementation can vary based on the library, generally, you would look for an event that indicates the completion of a write operation.

For example, if you are using a library like Plugin.BLE, you would subscribe to the WriteCompleted event or similar, which will notify you when the data has been successfully sent to the device. This event usually provides information about the success of the operation and may include the number of bytes sent.

Here’s a general approach:

1. Initiate the write operation to send your bytes.
2. Subscribe to the completion event that the library provides, which will notify you when the write operation is complete.
3. Handle the event to perform any actions needed after the bytes have been sent, such as updating the UI or logging the result.

Make sure to check the documentation of the specific BLE library you are using for the exact event names and parameters to use.