Build an iOS Custom Ringtone Calling App

In this tutorial, we will be creating an app that lets you call a person using a custom ringtone using app-to-app calls. Outgoing calls will specify a person to call, as well as a URL for the ringtone that will play when the person receives his or her incoming call. To get the most out of this tutorial, you will need a basic understanding of the following areas:

  • XCode
  • Objective-C
  • CocoaPods

ringtone call-out

A starter project has been provided with the appropriate app layout. You can download it from Github. The Storyboard should look something like this:


1. Setup

First, go to your Sinch Dashboard and create a new app. Take note of the application key and secret.

Now, use Terminal to navigate to your project directory, containing the appropriate Podfile, and run pod install. You will need to work out of the XCode workspace that has now been created.

2. Using SinchService

Head over to AppDelegate.h and add the following import statements:

#import <Sinch/Sinch.h>
#import <SinchService/SinchService.h>
#import "CallViewController.h"

Then, add the following property:

@property (strong, nonatomic) id<SINService> sinch;

Now go to AppDelegate.m. Allow for delegate assignment by adding to the interface:

@interface AppDelegate () <SINServiceDelegate, SINCallClientDelegate>

Now we can handle SinchService functionality in AppDelegate.

Find the method application:didFinishLaunchingWithOptions: and add the following code:

id config = [SinchService configWithApplicationKey:@"your-application-key"

id<SINService> sinch = [SinchService serviceWithConfig:config];
sinch.delegate = self;
sinch.callClient.delegate = self;

void (^onUserDidLogin)(NSString *) = ^(NSString *userId) {
    [sinch logInUserWithId:userId];

self.sinch = sinch;

[[NSNotificationCenter defaultCenter]
    usingBlock:^(NSNotification *note) { onUserDidLogin(note.userInfo[@"userId"]); }];

Be sure to fill in you application key and secret.

Since AppDelegate is a SinchService delegate, we can call the client:didReceiveIncomingCall: method to handle incomming calls. When we get a call, we want to display the call screen. We can do so by implementing client:didReceiveIncomingCall: as follows:

- (void)client:(id<SINCallClient>)client didReceiveIncomingCall:(id<SINCall>)call {
    UIViewController *top = self.window.rootViewController;
    CallViewController *controller = [top.storyboard instantiateViewControllerWithIdentifier:@"callScreen"];
    // 1
    [self.window.rootViewController presentViewController:controller animated:YES completion:nil];

Now let’s go to ViewController.m to log a user in once they click the login button. Implement the LoginAction method as follows:

- (IBAction)LoginAction:(id)sender {
    if (![self.UsernameTextField.text isEqualToString:@""]) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"UserDidLoginNotification"
                                                          userInfo:@{@"userId" : self.UsernameTextField.text}];

        [self performSegueWithIdentifier:@"showUserRingtone" sender:nil];

Next, add these imports to UserRingtoneViewController.h:

#import "AppDelegate.h"
#import "CallViewController.h"

In UserRingtoneViewController.m, add implement the following method:

- (id<SINCallClient>)callClient {
    return [[(AppDelegate *)[[UIApplication sharedApplication] delegate] sinch] callClient];

and add to the method CallAction: to make it look like this:

- (IBAction)CallAction:(id)sender {
    if (![self.UsernameTextField.text isEqualToString:@""]) {
        CallViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"callScreen"];

        NSDictionary *dict = [[NSDictionary alloc] initWithObjectsAndKeys:self.RingtoneTextField.text, @"url", nil];
        id<SINCall> call = [self.callClient callUserWithId:self.UsernameTextField.text headers:dict];
        // 2

        [self presentViewController:controller animated:YES completion:nil];

Here, we use the callUserWithId:headers: method. With this method, we are able to send information through a Sinch call. Since this method takes an NSDictionary as a parameter, we can send useful data such as contact info. We’ll be using this field to send a caller’s ringtone using a URL string.

Now, go to CallViewController.h and add these import statements:

#import <Sinch/Sinch.h>
#import <AVFoundation/AVFoundation.h>

and add to the interface line so that it reads as follows:

@interface CallViewController : UIViewController <SINCallClientDelegate, SINCallDelegate>

Finally, add the following properties:

@property (nonatomic, readwrite, strong) id<SINCall> call;
@property (strong, nonatomic) NSString *contact;
@property (strong, nonatomic) NSString *urlString;

3. Making Calls with Ringtones

We’ll want a way to play a sound file from a URL. Add the following property to CallViewController.h to add an AVPlayer object that can play URL sound files:

@property (strong, nonatomic) AVPlayer *player;

Next, head over to CallViewController.m. Add the following code to viewDidLoad:

if ([ direction] == SINCallDirectionIncoming) {
    self.AnswerButton.hidden = NO;
    self.ContactLabel.text = [NSString stringWithFormat:@"Call from %@",];
    NSString *urlString = [[_call headers] objectForKey:@"url"];
    NSURL *url = [NSURL URLWithString:urlString];
    self.player = [[AVPlayer alloc]initWithURL:url];
    [self.player play];

} else {
    self.AnswerButton.hidden = YES;
    NSString *contactName = [ remoteUserId];
    self.ContactLabel.text = [NSString stringWithFormat:@"Calling %@...", contactName];

Here, we use the direction property to dispay the appropriate call screen. If the user is receiving a call, we play the custom ringtone.

To set the call property, implement the call setter as follows:

- (void)setCall:(id<SINCall>)call {
    _call = call;
    _call.delegate = self;

In order to give the call screen buttons functionality, implement the methods AnswerAction and HangupAction as follows:

- (IBAction)AnswerAction:(id)sender {
    [ answer];
    self.AnswerButton.hidden = YES;

- (IBAction)HangupAction:(id)sender {
    [ hangup];

With SinchService, you are able to tell when a call has started and ended. You can also execute code at these stages. Let’s take advantage of this feature by adding the following:

- (void)callDidEstablish:(id<SINCall>)call {
    self.ContactLabel.text = [call remoteUserId];
    [self.player pause];

- (void)callDidEnd:(id<SINCall>)call {
    [self dismissViewControllerAnimated:YES completion:nil];

Now that we’ve set up the call screen, let’s set all of it’s properties whenever it is displayed.

First, go to AppDelegate.m. In the method client:didReceiveIncomingCall:, replace the // 1 comment with:

[controller setCall:call];
[controller setContact:[call remoteUserId]];

Finally, go to UserRingtoneViewController.m. In the method CallAction, replace the // 2 comment with:

[controller setCall:call];
[controller setContact:self.UsernameTextField.text];
[controller setUrlString:self.RingtoneTextField.text];

That’s it! You should be able to test the app out. There’s also a completed version of this app on Github.

login call-in

Custom ringtones is just one example of how you can send useful information over Sinch calls. By passing headers to a Sinch call, you can add to your app’s functionality.

For more tutorials, head over to the Sinch Tutorial Site or the Sinch Github.