As specified in our plugin.xml file's platform section for iOS, the implementation of our plugin in iOS is located at the src/ios/Sms.h and src/ios/Sms.m Objective-C files. The following code snippet shows the Sms.h file (the header file):

#import <Cordova/CDV.h>
#import <MessageUI/MFMessageComposeViewController.h>

@interface Sms : CDVPlugin <MFMessageComposeViewControllerDelegate> {
}

@property(strong) NSString* callbackID;
- (void)sendMessage:(CDVInvokedUrlCommand*)command;
@end

The preceding code declares an Sms class that extends CDVPlugin. It is important to note that in order to create a Cordova iOS plugin class, our Objective-C plugin class must extend the CDVPlugin class. In our Sms class declaration, there is a declared callbackID property of the NSString type and a declared sendMessage method, which returns void and takes CDVInvokedUrlCommand as a parameter. Now, let's move on to the Sms class implementation. The following code snippet shows the first part of the Sms.m file:

#import "Sms.h"

@implementation Sms

- (void)sendMessage:(CDVInvokedUrlCommand*)command
{
    CDVPluginResult* pluginResult = nil;
    NSString* phoneNumber = [command.arguments objectAtIndex:0];
    NSString* textMessage = [command.arguments objectAtIndex:1];

    self.callbackID = command.callbackId;

    if (![MFMessageComposeViewController canSendText]) {
        NSMutableDictionary* returnInfo = [NSMutableDictionary dictionaryWithCapacity:2];

        [returnInfo setObject:@"SMS_FEATURE_NOT_SUPPORTED" forKey:@"code"];
        [returnInfo setObject:@"SMS feature is not supported on this device" forKey:@"message"];

        pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_ERROR messageAsDictionary:returnInfo];

        [self.commandDelegate sendPluginResult:pluginResult callbackId:command.callbackId];

        return;
    }

    MFMessageComposeViewController *composeViewController = [[MFMessageComposeViewController alloc] init];
    composeViewController.messageComposeDelegate = self;

    NSMutableArray *recipients = [[NSMutableArray alloc] init];

    [recipients addObject:phoneNumber];

    [composeViewController setBody:textMessage];
    [composeViewController setRecipients:recipients];

    [self.viewController presentViewController:composeViewController animated:YES completion:nil];
}
// Code is omitted from here for simplicity
@end

In our Sms class implementation, we have the Objective-C instance method,- (void)sendMessage:(CDVInvokedUrlCommand*)command, which maps to the action parameter in the cordova.exec() JavaScript API.

In the sendMessage() method of our Sms class, the phoneNumber and message parameters are retrieved from the command.arguments parameter (phoneNumber is located at index 0 and message is located at index 1).

The MFMessageComposeViewController class provides a standard system user interface to compose text messages. Unlike Android, we cannot send SMS messages directly in iOS devices from our plugin code without using the default device's (iPhone or iPad) SMS application. In iOS, all we can do from our plugin code is use the MFMessageComposeViewController class to launch the SMS application with the SMS recipient and SMS message and listen for the user actions to know if the user sent or, cancelled, or failed to send the message. However, before interacting with the MFMessageComposeViewController class, we need to check whether the current iOS device is capable of sending text messages. This can be done using the canSendText method of MFMessageComposeViewController as [MFMessageComposeViewController canSendText].

If the iOS device does not have the feature to send text messages (which means that [MFMessageComposeViewController canSendText] returns NO), we will create a returnInfo object (that is of the NSMutableDictionary type), which contains two entries: one for the error code and the other one for the error message that tells the plugin user that the SMS feature is not supported on this device. Our plugin tells the JavaScript caller that the operation failed by calling the sendPluginResult method (of self.commandDelegate), which has the following signature:

- (void)sendPluginResult:(CDVPluginResult*)result callbackId:(NSString*)callbackId;

To this method, we pass a CDVPluginResult object (whose status is CDVCommandStatus_ERROR, and message is returnInfo) and callbackId, which is set to command.callbackId.

If your iOS device supports sending SMS messages, then a composeViewController object (of the MFMessageComposeViewController type) is created and initialized with recipients as the message recipients and textMessage as the message body. Then, we present composeViewController modally using the presentModalViewController method of self.viewController. It is important to highlight this line:

composeViewController.messageComposeDelegate = self;

This line tells composeViewController to send the message-related notifications to our Sms class. In order to receive these notifications, our Sms class needs to implement the messageComposeViewController method that has the following signature:

- (void)messageComposeViewController:(MFMessageComposeViewController *)controller didFinishWithResult:(MessageComposeResult)result

The messageComposeViewController class has the following parameters:

The following code snippet shows the implementation of messageComposeViewController in our Sms class:

- (void)messageComposeViewController:(MFMessageComposeViewController *)controller didFinishWithResult:(MessageComposeResult)result {
    BOOL succeeded = NO;
    NSString* errorCode = @"";
    NSString* message = @"";

    switch(result) {
        case MessageComposeResultSent:
            succeeded = YES;
            message = @"Message sent";
            break;
        case MessageComposeResultCancelled:
            message = @"Message cancelled";
            errorCode = @"SMS_MESSAGE_CANCELLED";
            break;
        case MessageComposeResultFailed:
            message = @"Message Compose Result failed";
            errorCode = @"SMS_MESSAGE_COMPOSE_FAILED";
            break;
        default:
            message = @"Sms General error";
            errorCode = @"SMS_GENERAL_ERROR";
            break;
    }

    [self.viewController dismissViewControllerAnimated:YES completion:nil];

    if (succeeded == YES) {
        [super writeJavascript:[[CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsString:message]
                                toSuccessCallbackString:self.callbackID]];
    } else {
        NSMutableDictionary* returnInfo = [NSMutableDictionary 
dictionaryWithCapacity:2];

        [returnInfo setObject:errorCode forKey:@"code"];
        [returnInfo setObject:message forKey:@"message"];

        [super writeJavascript:[[CDVPluginResult resultWithStatus:CDVCommandStatus_ERROR messageAsDictionary:returnInfo]
                                toErrorCallbackString:self.callbackID]];
    }
}

The messageComposeViewController method is called when the user taps on one of the buttons to dismiss the message composition interface. In the implementation of the messageComposeViewController method, the following two actions are performed:

These are the details of our SMS plugin implementation in iOS platform. Next, let's move to the Windows Phone 8 implementation of our plugin.