iOS Corebluetooth - Bluetooth scanner crashes on start-up - ios

Question

Edit: Now tested on my actual iphone, and I still get the same crash error
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSCFConstantString stringByAppendingString:]: nil argument'
When I ran the debugger, I ran through the debugger with breakpoints, but it did not reach any other function besides the tLog and the didLoad. The message "Bluetooth LE Device Scanner\r\n\r" went through the tLog a few times without before the app crashed because of the invalid argument
Original -
Info: Mac OSX Yosemite; Xcode 6.4; Using Objective C
Right now, I am following the video tutorial on setting up the bluetooth scanner to detect devices powered by bluetooth.
Video Links:
https://www.youtube.com/watch?v=zjr8qLE0sxk
https://www.youtube.com/watch?v=AjBpB4TcI-U (This part is where crash occurs)
I followed the code and understood the basics of core bluetooth framework. However, when running the test under both the iOS simulator and my iPhone, the application crashes at start-up.
The error I get is:
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSCFConstantString stringByAppendingString:]: nil argument' (iOS simulator)
I used the breakpoints that involve tlog and start-up, and that same error is still there because it is stuck printing the same thing.
Is there any fix I should do to get the basic bluetooth scanner running?
EDIT -
The code from the tutorial that I followed:
#import "ViewController.h"
#interface ViewController ()
// Now we need the properties to do various tasks for the device scanner
#property (weak, nonatomic) IBOutlet UITextView *outputTextView;
#property (weak, nonatomic) IBOutlet UISegmentedControl *verbositySelector;
#property (strong, nonatomic) CBCentralManager *centralManager;
#property (strong, nonatomic) CBPeripheral *discoveredPeripheral;
#property BOOL bluetoothOn;
#property (weak, nonatomic) IBOutlet UILabel *valueLabel;
#end
#implementation ViewController
-(bool)verboseMode
{
return (self.verbositySelector.selectedSegmentIndex != 0);
}
-(void)tlog:(NSString*)msg
{
self.outputTextView.text = [#"\r\n\r\n" stringByAppendingString:self.outputTextView.text];
self.outputTextView.text = [msg stringByAppendingString:self.outputTextView.text];
}
-(IBAction)startScan:(id)sender
{
if (!self.bluetoothOn){
[self tlog:#"Bluetooth is OFF"];
return;
}
[self.centralManager scanForPeripheralsWithServices:nil
options:
#{CBCentralManagerScanOptionAllowDuplicatesKey: #NO}];
}
// Standard template items added in by default. DO NOT REMOVE!
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self tlog:#"Bluetooth LE Device Scanner\r\n\r"];
self.bluetoothOn = NO;
self.centralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
// Core Bluetooth Tasks
-(void) centralManager:(CBCentralManager *)central
didDiscoverPeripheral:(CBPeripheral *)peripheral
advertisementData:(NSDictionary *)advertisementData
RSSI:(NSNumber *)RSSI
{
[self tlog:[NSString stringWithFormat:#"Discovered %#, RSSI: %#\n",
[advertisementData objectForKey:#"kCBAdvDataLocalName"], RSSI]];
self.discoveredPeripheral = peripheral;
if ([self verboseMode]){
[self.centralManager connectPeripheral:peripheral options:nil];
}
}
-(void) centralManager:(CBCentralManager *)central
didFailToConnectPeripheral:(CBPeripheral *)peripheral
error:(NSError *)error
{
}
-(void) centralManager:(CBCentralManager *)central
didConnectPeripheral:(CBPeripheral *)peripheral
{
}
-(void) peripheral:(CBPeripheral *)peripheral
didDiscoverServices:(NSError *)error
{
}
-(void) peripheral:(CBPeripheral *)peripheral
didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error
{
}
-(void) peripheral:(CBPeripheral *)peripheral
didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic
error:(NSError *)error
{
}
-(void) centralManagerDidUpdateState:(CBCentralManager *)central
{
if (central.state != CBCentralManagerStatePoweredOn){
[self tlog:#"Bluetooth OFF"];
self.bluetoothOn = NO;
}
else {
[self tlog:#"Bluetooth ON"];
self.bluetoothOn = YES;
}
}
#end