_photoUUID = [CBUUID UUIDWithString:bPhotocharacteristicUUID];
_photocharacteristic = [[CBMutableCharacteristic alloc] initWithType:_photoUUID
                                                          properties:CBCharacteristicPropertyRead
                                                               value:Nil
                                                         permissions:CBAttributePermissionsReadable];

我的理解是,当请求此值时,将会调用didRecieveRequest回调：

-(void) peripheralManager:(CBPeripheralManager *)peripheral didReceiveReadRequest:(CBATTRequest *)request {

    if ([request.characteristic.UUID isEqual:_photoUUID]) {
        if (request.offset > request.characteristic.value.length) {
            [_peripheralManager respondToRequest:request withResult:CBATTErrorInvalidOffset];
            return;
        }
        else {
            // Get the photos
            if (request.offset == 0) {
                _photoData = [NSKeyedArchiver archivedDataWithRootObject:_myProfile.photosImmutable];
            }

            request.value = [_photoData subdataWithRange:NSMakeRange(request.offset,request.characteristic.value.length - request.offset)];
            [_peripheralManager respondToRequest:request withResult:CBATTErrorSuccess];
        }
    }
}

这来自于Apple的文档.在中央方面,在didDiscoverCharacteristic回调我有以下代码：

if ([characteristic.UUID isEqual:_photoUUID]) {
    _photocharacteristic = characteristic;
    [peripheral readValueForCharacteristic:characteristic];
}

哪个又调用了didUpdateValueCorCharacteristic回调：

- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
    NSLog(@"updated value for characteristic");

    if ([characteristic.UUID isEqual:_photoUUID]) {
        NSArray * photos = [NSKeyedUnarchiver unarchiveObjectWithData:characteristic.value];
    }
}

所有的回调都被调用,但是当我尝试重新构造数组时,它被损坏,因为并不是所有的数据都被正确传输.我期望didRecieveReadRequest回调被多次调用,每次都有不同的偏移量.但是它只被称为一次.

我想知道有没有人知道我在做错什么？