Best Practices


Android Bluetooth is painful and that's being nice. This library attempts to deal with the necessary thread handling all internally.

All of the classes and members listed in this page can only be called from your Android project, not your PCL/Core library. You should call and set these values at your main launcher activity or even at an application level.

General Rules

While this library tries to deal with all of the known Android issues to the best of its ability. You likely will encounter issues if you don't follow the below:

  1. Don't scan or do anything with the adapter while connected to the GATT
  2. Don't overwhelm the radio. The library now has an internal queue to force operations to finish.
  3. GATT 133 will happen on Connect on occasion. Catch exceptions in the observable subscriptions.

Connection Options

Using androidAutoConnect is suggested in scenarios where you don't know if the device is in-range This will cause Android to connect when it sees the device. WARNING: initial connections take much longer with this option enabled

var device = CrossBleAdapter.Current.GetKnownDevice(guid);
device.Connect(new GattConnectionConfig {
	AndroidAutoConnect = true

Advanced Settings

The following values are only available to be set from your android project

// returns a suggestion on what thread to execute on.  This is not used internally
CrossBleAdapter.MainThreadSuggested { get; }

// defaults to MainThreadSuggested.  Background actions most android devices seem to throw an exception if not connected on the main thread
CrossBleAdapter.PerformActionsOnMainThread = true; 

CrossBleAdapter.MaxAutoReconnectAttempts { get; set; } = 5;

/// <summary>
/// Number of milliseconds to pause before service discovery (helps in combating GATT133 error) when service discovery is performed immediately after connection
/// DO NOT CHANGE this if you don't know what this is!
/// </summary>
CrossBleAdapter.PauseBeforeServiceDiscovery { get; set; } = TimeSpan.FromMilliseconds(750);

        /// <summary>
        /// Specifies the wait time before attempting an auto-reconnect
        /// DO NOT CHANGE if you don't know what this is!
        /// </summary>
CrossBleAdapter.PauseBetweenAutoReconnectAttempts { get; set; } = TimeSpan.FromSeconds(1);

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