Added setValue for strings

[agdl]

This fix allows to use setValue() for const char* variables

[kitsunami]

Can you provide the context for this?

[agdl]

Yes of course:

BLECharacteristic stringCharacteristic("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", BLERead | BLEWrite | BLENotify, MAX_LENGTH);
...
...
...
void myTestFunction(){
  char testString[] = "This is a test";
  stringCharacteristic.setValue(testString);
}

or something like:

BLECharacteristic stringCharacteristic("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", BLERead | BLEWrite | BLENotify, MAX_LENGTH);
...
...
...
void myTestFunction(){
 String testString = "Value is: " + thisValue;
  stringCharacteristic.setValue(testString.c_str());
}

[SidLeung]

The BLE library is undergo improvement. Will add in this change as part of the modification. Please note that "notification" is limited to 20 byte long. If the string you are sending out is longer than 20 byte, you may have to send it out in 20 byte segments. In that case, you can consider using an index pointer to walk down the string and specify the segment size for each setValue() call. You definitely do not want to just call setValue( myLongString );

[eriknyquist]

The change looks fine to me, but I'm not sure if it's a necessary one. @SidLeung the BLE master what do you think?

[sandeepmistry]

This is one of the API's that I forgot to port from BLEPeripheral. It makes it much nicer for setting a string value for the characteristic vs characteristic.setValue(str, strlen(str)). @agdl noticed it and created this PR to port it over.

More info. at: https://github.com/sandeepmistry/arduino-BLEPeripheral/blob/master/API.md#set-value

[SidLeung]

PR #461 addresses this issue. Will be in the next release. Please review and close.