Objective-c Checking NSArrray NSMutableArray empty or not

if([array count] ==0){
//array is empty
}

objective-c unique identifier for each iOS device

 if ([[UIDevice currentDevice] respondsToSelector:@selector(identifierForVendor)]) {

        

       str1=[NSString stringWithFormat:@"%@",

                             [[[UIDevice currentDevice] identifierForVendor] UUIDString]];

             

         }

objective-c substring of length

NSString* feng = [string substringToIndex:4]
NSString* zhong = [string substringFromIndex:5]

NSString to NSData

SString* myStr = @"This is the Testing String";

NSData* cData = [myStr dataUsingEncoding:NSUTF8StringEncoding];

Iphone: Volume control in IOS8

MPVolumeView* volumeView;

//find the volumeSlider

UISlider* volumeViewSlider;

for (UIView *view in [volumeView subviews]){

        if ([view.class.description isEqualToString:@"MPVolumeSlider"]){

            volumeViewSlider = (UISlider*)view;

            break;

        }

    }

    

    if (volumeViewSlider !=nil) {

         [volumeViewSlider setValue:volume animated:YES];

    }

In IOS7 it was

[[MPMusicPlayerController applicationMusicPlayer] setVolume:volume];

IPhone: IOS8 Error Trying to start MapKit location updates without prompting for location authorization

Here is my full code to get the MapKit Map View working in iOS8!

In your AppName-Info.plist Add a new row with the key name being:

NSLocationWhenInUseUsageDescription

And/Or

NSLocationAlwaysUsageDescription

With the value being a string of the message that you want to be displayed:

YourAppName would like to use your location.

In your header file. (I use App Name-Prefix.pch but YourViewController.h will work too)

#define IS_OS_8_OR_LATER ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)

self.locationManager = [[CLLocationManager alloc] init];
    if(IS_OS_8_OR_LATER) {
        [self.locationManager requestWhenInUseAuthorization];
        [self.locationManager requestAlwaysAuthorization];
    }

Sentiment Analysis: Good link

http://andybromberg.com/sentiment-analysis/