Advanced Configuration - iOS SDK

This document provides an oveview of some of the advanced configuration features of the Google Analytics SDK for iOS v3.

  1. Overview
  2. Initialization
  3. Setting and Sending Data
    1. Measurement Protocol Ampersand Syntax
    2. Using Multiple Trackers
    3. Default Tracker
  1. Sampling
  2. App-level Opt Out
  3. Anonymize IP
  4. Testing and Debugging
  5. Complete Example


The Google Analytics SDK for iOS provides a GAITracker class to set and send data to Google Analytics, and a GAI singleton that serves as an interface to the global configuration values of your implementation.


Before any data can be measured, you must initialize at least one tracker via GoogleAnalytics singleton by providing a name for the tracker and a Google Analytics property ID:

// Initialize a tracker using a Google Analytics property ID.
[[GAI sharedInstance] trackerWithTrackingId:@"UA-XXXX-Y"];

Now this tracker can be used for setting and sending data to Google Analytics.

Setting and Sending Data

Data is sent to Google Analytics by setting maps of parameter-value pairs on the tracker and sending them via the set and send methods:

 * Send a screen view to Google Analytics by setting a map of parameter
 * values on the tracker and calling send.

// Retrieve tracker with placeholder property ID.
id<GAITracker> tracker = [[GAI sharedInstance] trackerWithTrackingId:@"UA-XXXX-Y"];

NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:
                            @"appview", kGAIHitType, @"Home Screen", kGAIScreenName, nil];
[tracker send:params];

The GAIDictionaryBuilder class simplifies the process of building hits and is recommended for most use cases. Here we can send the same screen view with fewer lines of code:

// Sending the same screen view hit using [GAIDictionaryBuilder createAppView]
[tracker send:[[[GAIDictionaryBuilder createAppView] set:@"Home Screen"
                                                  forKey:kGAIScreenName] build]];

Measurement Protocol Ampersand Syntax

Values may also be set on a single hit, by setting the value on a Builder, or on all subsequent hits, by setting it on the tracker object itself, using the Measurement Protocol amperstand syntax:

// Sending the same screen view hit using amperstand syntax.
[tracker send:[[[GAIDictionaryBuilder createAppView] set:@"&cd;"
                                                  forKey:kGAIScreenName] build]];

For the complete list of available measurement protocol parameters, see the Measurement Protocol Parameter Reference.

Applying Values to Multiple Hits

Any values set on the tracker directly will be persisted and applied to muliple hits, as in this example:

// May return nil if a tracker has not yet been initialized with
// a property ID.
id<GAITracker> tracker = [[GAI sharedInstance] defaultTracker];

// Set screen name on the tracker to be sent with all hits.
[tracker set:kGAIScreenName
       value:@"Home Screen"];

// Send a screen view for "Home Screen".
[tracker send:[[GAIDictionaryBuilder createAppView] build]];

// This event will also be sent with &cd=Home%20Screen.
[tracker send:[[GAIDictionaryBuilder createEventWithCategory:@"UX"
                                                       value:nil] build]];

// Clear the screen name field when we're done.
[tracker set:kGAIScreenName

Only values that you want to persist across multiple hits should be set directly on the tracker. Setting a screen name on a tracker would make sense, since the same value can be applied to subsequent screen view and event hits. However, it is not recommended to set a field like hit type on the tracker, because it will likely change with each hit.

Using Multiple Trackers

Mutiple trackers may be used in a single implementation, which can be useful for sending data to multiple properties:

id<GAITracker> tracker1 = [[GAI sharedInstance] trackerWithTrackingId:@"UA-XXXX-1"];

// Trackers may be named. By default, name is set to the property ID.
id<GAITracker> tracker2 = [[GAI sharedInstance] trackerWithName:@"altTracker"

[tracker1 set:kGAIScreenName
        value:@"Home Screen"];

[tracker2 set:kGAIScreenName
        value:NSStringFromClass([self class])];

// Send a screenview to UA-XXXX-1.
[tracker1 send:[[GAIDictionaryBuilder createAppView] build]];

// Send a screenview to UA-XXXX-2.
[tracker2 send:[[GAIDictionaryBuilder createAppView] build]];

Automated measurement features, like automatic screen and uncaught exception measurement, will only use one tracker to send data to Google Analytics. If you are using these features and want to send data using other trackers, you will need to do so manually.

For reference, automatic screen measurement uses the tracker specified in the tracker property of a given GAITrackedViewController. Uncaught exception measurement uses the default tracker specified in your GAI instance.

Using the Default Tracker

Google Analytics maintains a default tracker. The first tracker initialized becomes the default tracker but may be overridden:

// t1 becomes the default tracker because it is the first tracker initialized.
id<GAITracker> t1 = [[GAI sharedInstance] trackerWithTrackingId:@"UA-XXXX-1"];

id<GAITracker> t2 = [[GAI sharedInstance] trackerWithTrackingId:@"UA-XXXX-2"];

// Returns t1.
id<GAITracker> defaultTracker = [[GAI sharedInstance] defaultTracker];

// Hit sent to UA-XXXX-1.
[defaultTracker send:[[[GAIDictionaryBuilder createAppView]
                set:@"Home Screen" forKey:kGAIScreenName] build]];

// Override the default tracker.
[[GAI sharedInstance] setDefaultTracker:t2];

// Returns t2.
defaultTracker = [[GAI sharedInstance] defaultTracker];

// Hit sent to UA-XXXX-2.
[defaultTracker send:[[[GAIDictionaryBuilder createAppView]
                       set:NSStringFromClass([self class])
                    forKey:kGAIScreenName] build]];


You can enable client-side sampling to limit the number of hits sent to Google Analytics. If your app has a large number of users or otherwise sends a large volume of data to Google Analytics, enabling sampling will help ensure un-interrupted reporting.

For example, to implement client-side sampling at a rate of 50%, use the following code:

// Assumes a tracker has already been initialized with a property ID, otherwise
// getDefaultTracker returns nil.
id<GAITracker> tracker = [[GAI sharedInstance] defaultTracker];

// Set a sample rate of 50%.
[tracker set:kGAISampleRate value:@"50.0"];

App-level Opt Out

You can enable an app-level opt out flag that will disable Google Analytics across the entire app. Note that this flag must be set each time the app starts up and will default to false.

To get the app-level opt out setting, use:

// Get the app-level opt out preference.
if ([GAI sharedInstance].optOut) {
  ... // Alert the user they have opted out.

To set the app-level opt out, use:

// Set the app-level opt out preference.
[[GAI sharedInstance] setOptOut:YES];

Anonymize IP

Enabling anonymize IP functionality tells Google Analytics to anonymize the IP information sent by the SDK by removing the last octet of the IP address prior to its storage.

The following example shows how to enable the anonymize IP functionality for a tracker:

[tracker set:kGAIAnonymizeIp value:@"1"];

Anonymize IP functionality can be set at any time.

Testing and Debugging

The Google Analytics SDK for iOS provides tools to make testing and debugging easier.

Dry Run

The SDK provides a dryRun flag that when set, prevents any data from being sent to Google Analytics. The dryRun flag should be set whenever you are testing or debugging an implementation and do not want test data to appear in your Google Analytics reports.

To set the dry run flag:

[[GAI sharedInstance] setDryRun:YES];


The GAILogger protocol is provided to handle useful messages from the SDK at these levels of verbosity: error, warning, info, and verbose.

The SDK initializes a standard Logger implementation, which by default will only log warning or error messages to console. To set the verbosity of the Logger:

// Set the log level to verbose.
[[GAI sharedInstance].logger setLogLevel:kGAILogLevelVerbose];

Custom implementations of Logger can also be used:

// Provide a custom logger.
[[GAI sharedInstance].logger = [[CustomLogger alloc] init];

Complete Example

The example below shows the code required to initialize a Google Analytics implementation and send a single screen view.

Next, a screen view is measured when a the first screen is displayed to a user:

Typically the initialization of an implementation can be done from the app delegate, as in this example:

//  AppDelegate.h

#import <UIKit/UIKit.h>
#import "GAI.h"

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;
@property (strong, nonatomic) id<GAITracker> tracker;


//  AppDelegate.m

#import "AppDelegate.h"

/** Google Analytics configuration constants **/
static NSString *const kGaPropertyId = @"UA-XXXX-Y"; // Placeholder property ID.
static NSString *const kTrackingPreferenceKey = @"allowTracking";
static BOOL const kGaDryRun = NO;
static int const kGaDispatchPeriod = 30;

@interface AppDelegate ()

- (void)initializeGoogleAnalytics;


@implementation AppDelegate
- (void)applicationDidBecomeActive:(UIApplication *)application {
    [GAI sharedInstance].optOut =
    ![[NSUserDefaults standardUserDefaults] boolForKey:kTrackingPreferenceKey];

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
    // Do other work for customization after application launch
    // then initialize Google Analytics.
    [self initializeGoogleAnalytics];

    return YES;

- (void)initializeGoogleAnalytics: {

    [[GAI sharedInstance] setDispatchInterval:kGaDispatchPeriod];
    [[GAI sharedInstance] setDryRun:kDryRun];
    self.tracker = [[GAI sharedInstance] trackerWithTrackingId:kGaPropertyId];

   // The rest of the app delegate code omitted.


Then, to measure a screen view when a view is displayed to a user:

// MyViewController.m
#import "MyViewController.h"
#import "AppDelegate.h"
#import "GAI.h"
#import "GAIFields.h"
#import "GAITracker.h"
#import "GAIDictionaryBuilder.h"

@implementation MyViewController

- (void)viewDidAppear {

    [super viewDidAppear];

    // This screen name value will remain set on the tracker and sent with
    // hits until it is set to a new value or to nil.
    [[GAI sharedInstance].defaultTracker set:kGAIScreenName
                                       value:@"Home Screen"];

    // Send the screen view.
    [[GAI sharedInstance].defaultTracker
        send:[[GAIDictionaryBuilder createAppView] build]];