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Bug fix: fixed service discovery delay

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Aleksander Nowakowski
2017-03-16 13:51:10 +01:00
parent c07824c38a
commit 54de8e6d9e
2 changed files with 20 additions and 26 deletions
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29
app/src/main/java/no/nordicsemi/android/nrftoolbox/profile/BleManager.java
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@@ -1156,29 +1156,20 @@ public abstract class BleManager<E extends BleManagerCallbacks> implements ILogg
* The onConnectionStateChange event is triggered just after the Android connects to a device.
* In case of bonded devices, the encryption is reestablished AFTER this callback is called.
* Moreover, when the device has Service Changed indication enabled, and the list of services has changed (e.g. using the DFU),
* the indication is received few milliseconds later, depending on the connection interval.
* When received, Android will start performing a service discovery operation itself, internally.
* the indication is received few hundred milliseconds later, depending on the connection interval.
* When received, Android will start performing a service discovery operation on its own, internally,
* and will NOT notify the app that services has changed.
*
* If the mBluetoothGatt.discoverServices() method would be invoked here, if would returned cached services,
* If the gatt.discoverServices() method would be invoked here with no delay, if would return cached services,
* as the SC indication wouldn't be received yet.
* Therefore we have to postpone the service discovery operation until we are (almost, as there is no such callback) sure, that it had to be handled.
* Our tests has shown that 600 ms is enough(*). It is important to call it AFTER receiving the SC indication, but not necessarily
* after Android finishes the internal service discovery.
*
* (*) - While testing on Nexus 4 with Android 5.0.1 it appeared that 600 ms may be not enough.
* The service discovery initiated by the system was still in progress while gatt.serviceDiscovery() below
* was called and (due to a bug on older Android versions, where there can be only one callback registered)
* the onServicesDiscovered(...) callback has never been called.
* Therefore we have to postpone the service discovery operation until we are (almost, as there is no such callback) sure,
* that it has been handled.
* TODO: Please calculate the proper delay that will work in your solution.
* It should be greater than the time from LLCP Feature Exchange to ATT Write for Service Change indication.
* If your device does not use Service Change indication (for example does not have DFU) the delay may be 0.
*/
// On Android Nougat or never devices no delay is necessary any more.
final boolean bonded = gatt.getDevice().getBondState() == BluetoothDevice.BOND_BONDED;
int delay = 0;
// TODO: modify the delay to match your use case. More services require longer discovery time. Use Nexus 4, 7 or other phone with bad throughput.
// The delays here are based on a guess. Newer phones should handle service discovery it faster, I guess.
if (bonded && Build.VERSION.SDK_INT < Build.VERSION_CODES.N)
delay = 600;
if (bonded && Build.VERSION.SDK_INT < Build.VERSION_CODES.M)
delay = 1200;
final int delay = bonded ? 1600 : 0; // around 1600 ms is required when connection interval is ~45ms.
if (delay > 0)
Logger.d(mLogSession, "wait(" + delay + ")");
mHandler.postDelayed(new Runnable() {