Terminating app due to uncaught exception '_HKObjectValidationFailureException' - ios

Question

I am saving the blood glucose values into Health Kit application in iOS.
-(void)viewDidLoad
{
float bloodGlucose=20;
float bloodGlucoseValue= (int) bloodGlucose;
NSLog(#"Blood Glucose value is :%f",bloodGlucoseValue);
HKQuantityType *bloodGlucoseType=[HKQuantityType quantityTypeForIdentifier:HKQuantityTypeIdentifierBloodGlucose];
NSSet *requesObjects=[[NSSet alloc]initWithObjects:bloodGlucoseType, nil];
HKHealthStore * hStore = [HKHealthStore new];
[hStore requestAuthorizationToShareTypes: requesObjects readTypes:requesObjects completion:^(BOOL success, NSError *error) {
//user response processing goes here, i.e.
if(success) {
dispatch_async(dispatch_get_main_queue(), ^{
[[GSHealthKitManager sharedManager]saveBloodGlucosePercentageintoHealthStore:bloodGlucoseValue];
});
}
}];
}
-(void)saveBloodGlucosePercentageintoHealthStore:(float)bloodGlucoseValue
{
HKUnit *inches=[HKUnit gramUnit];
HKQuantity * glucoseQuantity = [HKQuantity quantityWithUnit:inches doubleValue:bloodGlucoseValue];
HKQuantityType *glucoseType = [HKQuantityType quantityTypeForIdentifier:HKQuantityTypeIdentifierBloodGlucose];
NSDate *now = [NSDate date];
HKQuantitySample *bloodGlucosesample = [HKQuantitySample quantitySampleWithType:glucoseType quantity:glucoseQuantity startDate:now endDate:now];
[self.healthStore saveObject:bloodGlucosesample withCompletion:^(BOOL success, NSError *error){
if (!success)
{
NSLog(#"Error");
}
}];
}
If I run the application, I got following exception in this line of code:
HKQuantitySample *bloodGlucosesample = [HKQuantitySample quantitySampleWithType:glucoseType quantity:glucoseQuantity startDate:now endDate:now];
Trace:
Exception is: Terminating app due to uncaught exception '_HKObjectValidationFailureException', reason: 'HKQuantitySample 20 g 2016-04-07 15:39:44 +0530 2016-04-07 15:39:44 +0530 requires unit of type Mass/Volume. Incompatible unit: g'
*** First throw call stack:
(
0 CoreFoundation 0x00b73a14 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x00634e02 objc_exception_throw + 50
2 CoreFoundation 0x00b7393d +[NSException raise:format:] + 141
3 HealthKit 0x0010da70 -[HKObject _validateForCreation] + 149
4 HealthKit 0x0010d89e +[HKObject _newDataObjectWithMetadata:device:config:] + 273
5 HealthKit 0x0014e661 +[HKSample _newSampleWithType:startDate:endDate:device:metadata:config:] + 200
6 HealthKit 0x0013244f +[HKQuantitySample quantitySampleWithType:quantity:startDate:endDate:device:metadata:] + 324
7 HealthKit 0x0013265a +[HKQuantitySample quantitySampleWithType:quantity:startDate:endDate:] + 116
8 HealthKitProto 0x0005cda2 -[GSHealthKitManager saveBloodGlucosePercentageintoHealthStore:] + 274
9 HealthKitProto 0x0005f4c7 __34-[FirstViewController viewDidLoad]_block_invoke_9 + 103
10 libdispatch.dylib 0x0367a377 _dispatch_call_block_and_release + 15
11 libdispatch.dylib 0x0369d9cd _dispatch_client_callout + 14
12 libdispatch.dylib 0x03682f90 _dispatch_main_queue_callback_4CF + 910
13 CoreFoundation 0x00ac4fde __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 14
14 CoreFoundation 0x00a82cd4 __CFRunLoopRun + 2356
15 CoreFoundation 0x00a820e6 CFRunLoopRunSpecific + 470
16 CoreFoundation 0x00a81efb CFRunLoopRunInMode + 123
17 GraphicsServices 0x04523664 GSEventRunModal + 192
18 GraphicsServices 0x045234a1 GSEventRun + 104
19 UIKit 0x00f02bfa UIApplicationMain + 160
20 HealthKitProto 0x000603ba main + 138
21 libdyld.dylib 0x036c7a21 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

It seems that grams is not an unit supported by healthkit.
Check the allowed units in the SDK documentation and here
Edit: You specify a bad unit for this value
HKUnit *inches=[HKUnit gramUnit]; // this is not the right unit (nor inches)
HKQuantity * glucoseQuantity = [HKQuantity quantityWithUnit:inches doubleValue:bloodGlucoseValue];
You should create a mass unit and volume unit then divide the first by the second one (in swift):
let milligramPerDeciLiter = HKUnit.gramUnitWithMetricPrefix(.Milli).unitDividedByUnit(HKUnit.literUnitWithMetricPrefix(.Deci))
In Objc :
HKUnit* milligramPerDeciLiter = [[HKUnit gramUnitWithMetricPrefix:HKMetricPrefixMilli] unitDividedByUnit:[HKUnit literUnitWithMetricPrefix:HKMetricPrefixDeci]];