# Overview You can define variables using the CleverTap iOS SDK. When you define a variable in your code, you can sync them to the CleverTap Dashboard via the provided SDK methods. # Supported Variable Types Currently, CleverTap SDK supports the following variable types: - String - boolean - Dictionary - int - float - double - short - long - Number # Define Variables Variables can be defined using a shared or custom CleverTap instance. The Variable is defined using the `defineVar` method, which returns an instance of a `CTVar` variable. You must provide the name and default value of the variable. ```swift // Swift // Primitive types let var_string = CleverTap.sharedInstance()?.defineVar(name: "var_string", string: "hello, world") let var_int = CleverTap.sharedInstance()?.defineVar(name: "var_int", integer: 10) let var_bool = CleverTap.sharedInstance()?.defineVar(name: "var_bool", boolean: true) let var_float = CleverTap.sharedInstance()?.defineVar(name: "var_float", float: 6.0) let var_double = CleverTap.sharedInstance()?.defineVar(name: "var_double", double: 60.999) let var_short = CleverTap.sharedInstance()?.defineVar(name: "var_short", short: 1) let var_number = CleverTap.sharedInstance()?.defineVar(name: "var_number", number: NSNumber(value: 32)) let var_long = CleverTap.sharedInstance()?.defineVar(name: "var_long", long: 64) // Dictionary let var_dict = CleverTap.sharedInstance()?.defineVar(name: "var_dict", dictionary: [ "nested_string": "hello, nested", "nested_double": 10.5 ]) let var_dict_nested = CleverTap.sharedInstance()?.defineVar(name: "var_dict_complex", dictionary: [ "nested_int": 1, "nested_string": "hello, world", "nested_map": [ "nested_map_int": 15, "nested_map_string": "hello, nested map", ] ]) ``` ```objectivec // Objective-C #import // Primitive types CTVar *var_string = [[CleverTap sharedInstance] defineVar:@"var_string" withString:@"hello, world"]; CTVar *var_int = [[CleverTap sharedInstance] defineVar:@"var_int" withInt:10]; CTVar *var_bool = [[CleverTap sharedInstance] defineVar:@"var_bool" withBool:YES]; CTVar *var_float = [[CleverTap sharedInstance] defineVar:@"var_float" withFloat:6.0]; CTVar *var_double = [[CleverTap sharedInstance] defineVar:@"var_double" withDouble:60.999]; CTVar *var_short = [[CleverTap sharedInstance] defineVar:@"var_short" withShort:1]; CTVar *var_number = [[CleverTap sharedInstance] defineVar:@"var_number" withNumber:[[NSNumber alloc] initWithInt:32]]; CTVar *var_long = [[CleverTap sharedInstance] defineVar:@"var_long" withLong:64]; // Dictionary CTVar *var_dict = [[CleverTap sharedInstance] defineVar:@"var_dict" withDictionary:@{ @"nested_string": @"hello, nested", @"nested_double": @10.5 }]; CTVar *var_dict_nested = [[CleverTap sharedInstance] defineVar:@"var_dict_complex" withDictionary:@{ @"nested_int": @1, @"nested_string": @"hello, world", @"nested_map": @{ @"nested_map_int": @15, @"nested_map_string": @"hello, nested map", } }]; ``` # Setup Callbacks CleverTap iOS SDK provides several callbacks for the developer to receive feedback from the SDK. You can use them as per your requirement, using all of them is not mandatory. They are as follows: - Status of fetch variables request - `onVariablesChanged` - `onceVariablesChanged` - `onValueChanged` - Variables Delegate ## Status of Variables Fetch Request This method provides a boolean flag to ensure that the variables are successfully fetched from the server. ```swift // Swift CleverTap.sharedInstance()?.fetchVariables({ success in print(success) }) ``` ```objectivec // Objective-C #import [[CleverTap sharedInstance] fetchVariables:^(BOOL success) { }]; ``` ## `onVariablesChanged` This callback is invoked when variables are initialized with values fetched from the server. It is called each time new values are fetched. ```swift // Swift let var_string = CleverTap.sharedInstance()?.defineVar(name: "myString", string: "hello,world") CleverTap.sharedInstance()?.onVariablesChanged { print("CleverTap.onVariablesChanged: \(var_string?.value ?? "")") } ``` ```objectivec // Objective-C #import CTVar *var_string = [[CleverTap sharedInstance] defineVar:@"var_string" withString:@"hello, world"]; [[CleverTap sharedInstance] onVariablesChanged:^{ NSLog(@"CleverTap.onVariablesChanged: %@", [var_string value]); }]; ``` ## `onceVariablesChanged` This callback is invoked when variables are initialized with values fetched from the server. It is called only once. ```swift // Swift let var_string = CleverTap.sharedInstance()?.defineVar(name: "myString", string: "hello,world") CleverTap.sharedInstance()?.onceVariablesChanged { print("CleverTap.onceVariablesChanged: \(var_string?.value ?? "")") } ``` ```objectivec // Objective-C #import CTVar *var_string = [[CleverTap sharedInstance] defineVar:@"var_string" withString:@"hello, world"]; [[CleverTap sharedInstance] onceVariablesChanged:^{ // Executed only once NSLog(@"CleverTap.onceVariablesChanged: %@", [var_string value]); }]; ``` ## `onValueChanged` This callback is invoked when the value of the variable changes. ```swift // Swift let var_string = CleverTap.sharedInstance()?.defineVar(name: "myString", string: "hello,world") var_string?.onValueChanged { print("var_string.onValueChanged: \(var_string?.value ?? "")") } ``` ```objectivec // Objective-C #import CTVar *var_string = [[CleverTap sharedInstance] defineVar:@"var_string" withString:@"hello, world"]; [var_string onValueChanged:^{ NSLog(@"var_string.onValueChanged: %@", [var_string value]); }]; ``` ## Variables Delegate The `VarDelegate` method is implemented to be invoked when the variable value is changed. ```swift // Swift @objc class VarDelegateImpl: NSObject, VarDelegate { func valueDidChange(_ variable: CleverTapSDK.Var) { print("CleverTap \(String(describing: variable.name)):valueDidChange to: \(variable.value!)") } } var_string?.setDelegate(self) ``` ```objectivec // Objective-C #import @interface CTVarDelegateImpl : NSObject @end @implementation CTVarDelegateImpl - (void)valueDidChange:(CTVar *)variable { // valueDidChange } @end CTVarDelegateImpl *del = [[CTVarDelegateImpl alloc] init]; [var_string setDelegate:del]; ``` # Sync Defined Variables After defining your variables in the code, you must send/sync variables to the server. To do so, the app must be in DEBUG mode and mark a particular CleverTap user profile as a test profile from the CleverTap dashboard. [Learn how to mark a profile as **Test Profile**](https://developer.clevertap.com/docs/concepts-user-profiles#mark-a-user-profile-as-a-test-profile) After marking the profile as a test profile, you must sync the app variables in DEBUG mode: ```swift // Swift // 1. Define CleverTap variables // … // 2. Add variables/values changed callbacks // … // 3. Sync CleverTap Variables from DEBUG mode/builds CleverTap.sharedInstance()?.syncVariables(); ``` ```objectivec // Objective-C // 1. Define CleverTap variables // … // 2. Add variables/values changed callbacks // … // 3. Sync CleverTap Variables from DEBUG mode/builds [[CleverTap sharedInstance] syncVariables]; ``` > 📘 Key Points to Remember > > - In a scenario where there is already a draft created by another user profile in the dashboard, the sync call will fail to avoid overriding important changes made by someone else. In this case, Publish or Dismiss the existing draft before you proceed with syncing variables again. However, you can override a draft you created via the sync method previously to optimize the integration experience. > - You can receive the following console logs from the CleverTap SDK: > - Variables synced successfully. > - Unauthorized access from a non-test profile. Please mark this profile as a test profile from the CleverTap dashboard. # Fetch Variables During a Session You can fetch the updated values for your CleverTap variables from the server during a session. If variables have changed, the appropriate callbacks will be fired. The provided callback provides a boolean flag that indicates if the fetch call was successful. The callback is fired regardless of whether the variables have changed or not. ```swift // Swift CleverTap.sharedInstance()?.fetchVariables({ success in print(success) }) ``` ```objectivec // Objective-C [[CleverTap sharedInstance] fetchVariables:^(BOOL success) { }]; ``` # Use Fetched Variables Values This process involves the following two major steps: 1. Fetch variable values. 2. Access variable values. ## Fetch Variable Values Variables are updated automatically when server values are received. If you want to receive feedback when a specific variable is updated, use the individual callback: ```swift // Swift variable?.onValueChanged { print("variable.onValueChanged: \(variable?.value ?? "")") } ``` ```objectivec // Objective-C [variable onValueChanged:^{ NSLog(@"variable.onValueChanged: %@", [variable value]); }]; ``` ## Access Variable Values You can access these fetched values in the following three ways: ### From `Var` instance You can use several methods on the `Var` instance as shown in the following code: ```swift // Swift variable?.defaultValue // returns default value variable?.value // returns current value variable?.numberValue // returns value as NSNumber if applicable variable?.stringValue // returns value as String ``` ```objectivec // Objective-C variable.defaultValue; // returns default value variable.value; // returns current value variable.numberValue; // returns value as NSNumber if applicable variable.stringValue; // returns value as String ``` ### Using `CleverTap` Instance method You can use the `CleverTap` instance method to get the current value of a variable. If the variable is nonexistent, the method returns `null`: ```swift // Swift CleverTap.sharedInstance()?.getVariableValue("variable name") ``` ```objectivec // Objective-C [[CleverTap sharedInstance]getVariableValue:@"variable name"]; ```