Making SMS ViewController pop up on iPhone using Unity3D

Question

I am having trouble getting MFMessageCompose to work with Unity3D iOS Plugin.

I got an alert window to pop up with buttons but I am having an error when accessing the MFMessageComposer. Can't seem to get the method to pop up the window properly.

Here is my iOSBridge.h (linked file if you want):

#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import <MessageUI/MessageUI.h>

@interface Delegate : NSObject <UINavigationControllerDelegate, MFMessageComposeViewControllerDelegate>

@end

And my iOSBridge.mm file:

#import "iOSBridge.h"

@implementation Delegate


//Trying to still understand the meaning behind this line.  Why???
-(id)init
{
    return self;
}

//RATE US Button Numbers
//Not entirely sure What I did here but it still bring it up.  This section has nothing to do with SMS
-(void) alertView: (UIAlertView*)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    //Give back the number of the button

    NSString *inStr = [NSString stringWithFormat:@"%d", (int)buttonIndex];
    const char *cString = [inStr cStringUsingEncoding:NSASCIIStringEncoding];
    UnitySendMessage("Popup", "UserFeedBack", cString);
    NSLog(@"%li", (long)buttonIndex);
} // RATE US button number end

-(void)SMS:(id)sender{

    MFMessageComposeViewController *controller = [[MFMessageComposeViewController alloc] init];
    [controller setMessageComposeDelegate:self];

    if([MFMessageComposeViewController canSendText]){

        [controller setRecipients:[NSArray arrayWithObjects:nil]];
        [controller setBody:[NSString stringWithFormat:@"Text"]];

        //WHYYY do you not work
        //[self presentViewController:controller animated:YES];

        Delegate *appDelegate = UIApplication.sharedApplication.delegate;
        [appDelegate.window.rootViewController presentViewController:controller animated:YES completion:nil]
    }

}

@end

static Delegate* delegateObject;

extern "C"
{

//A method for unity can run
void _AddNotification(const char* title,
                  const char* body,
                  const char* cancelLabel,
                  const char* firstLabel,
                  const char* secondLabel)

{

//Don't have a full grasp of this delegateObject thing yet.
if(delegateObject ==nil){
    delegateObject = [[Delegate alloc]init];
}

//iOS Alert Pop up view RATE OUR GAME

UIAlertView *alert = [[UIAlertView alloc]
                      initWithTitle: [NSString stringWithUTF8String:title]
                      message:[NSString stringWithUTF8String:body] delegate:delegateObject
                      cancelButtonTitle:[NSString stringWithUTF8String:cancelLabel]
                      otherButtonTitles:[NSString stringWithUTF8String:firstLabel],[NSString stringWithUTF8String:secondLabel], nil];


    [alert show];
} //End of _AddNotification


//SMS Method for Unity to use
void _SMSGO(const char* Mbody){

        MFMessageComposeViewController *controller = [[MFMessageComposeViewController alloc] init];
        if([MFMessageComposeViewController canSendText]){

            NSString *s = [NSString stringWithFormat:@"%s", Mbody];
            controller.body = s;

            //Suppose to Brings up the SMS view not sure why it isnt working or how to make this work
            //If this can work its major progress

            [delegateObject presentViewController:controller animated:YES];
        }
    }
}

Answer 1

So these:

-(void) alertView: (UIAlertView*)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    NSString *inStr = [NSString stringWithFormat:@"%d", (int)buttonIndex];
    const char *cString = [inStr cStringUsingEncoding:NSASCIIStringEncoding];
    UnitySendMessage("Popup", "UserFeedBack", cString);
    NSLog(@"%li", (long)buttonIndex);
}

-(void)SMS:(id)sender{

    MFMessageComposeViewController *controller = [[MFMessageComposeViewController alloc] init];
    [controller setMessageComposeDelegate:self];

    if([MFMessageComposeViewController canSendText]){

        [controller setRecipients:[NSArray arrayWithObjects:nil]];
        [controller setBody:[NSString stringWithFormat:@"Text"]];

        //WHYYY do you not work
        //[self presentViewController:controller animated:YES];

        Delegate *appDelegate = UIApplication.sharedApplication.delegate;
        [appDelegate.window.rootViewController presentViewController:controller animated:YES completion:nil]
    }    
}

Code blocks are actually not being accessed at all through your bridge. So nothing in this will be touched at all.

The - (id) init is the initializer of the class. So in order to access anything in that file from anything else, you have to init it first. An easier way to think of this is:

extern.c is a separate file.

static Delegate *delObj;

extern "C"
{
    void _callMain (const char *hello) {
        /**
         * delObj is a static so it "Will be once it is" so it will be
         * in memory (mallocated) the moment you tell it to be something.
         */
        if (!delObj) {

In this case, we want that static object to be an instance of Delegate (not a particularly good name to set your class to, it will lead to much confusion). We "start" or initialize this class by calling init and we tell it this is an object we need, chuck it on the heap read this.

        delObj = [[Delegate alloc] init];
    }

    // Now we can call the function in the next file
    [delObj helloWorld];
}

Delegate.m - Think of this as a different file. You can access this file from extern.c because (in reality) it's just included in the same file. But this of this as a separate entity entirely. You have to access this "file" from extern.c

@implementation Delegate

// This is the function we call with [[Delegate alloc] init];
-(id) init {
    // It simply returns itself - saying hey this is the object memory chunk in the heap you want to talk to.
    return self;
}

// This is the function we call with [delObj helloWorld];
- (void) helloWorld {
    NSLog("Hello World"); // This will show up in your console.
}

So the above code has two functions, one that says "this is the memory object your looking for" - one that says "I'm a function, lets execute something".

Now with all that laid out, you're not calling:

-(void) alertView: (UIAlertView*)alertView clickedButtonAtIndex:(NSInteger)buttonIndex

OR

-(void)SMS:(id)sender{

Via your extern "C". The reason why _AddNotification works is because you have code in there calling UIAlertView AFTER making sure your delegateObject is in memory. In you _SMSGO function, you're not putting your object into memory. So when you call delegateObject in [delegateObject presentViewController:controller animated:YES]; it says "Oh I know what delegateObject is but it's equal to nothing. In fact it does not have memory to execute anything!" Thats why you probably don't get any errors or exceptions. The code knows there is a static object, but it hasn't been set to anything yet.

SOLUTION:

First, void methods don't need :(id)sender thats more of a IBAction thing unless you actually want to send something - so change -(void)SMS:(id)sender{ to - (void) SMS { (with the pretty spacing, too. It's mo' better for eyes).

Second, swap everything in SMS with:

- (void) SMS {

    MFMessageComposeViewController *controller = [[MFMessageComposeViewController alloc] init];
    [controller setMessageComposeDelegate:self];

    if([MFMessageComposeViewController canSendText]){

        [controller setRecipients:[NSArray arrayWithObjects:nil]];
        [controller setBody:[NSString stringWithFormat:@"Text"]];

        // We now know why we work!
        [self presentViewController:controller animated:YES];
    }    
}

But WAIT! And do not copy and paste. Be sure to understand each line of code you write.

This line allocates an object into memory, in this instance, the MFMessageComposeViewController object. Then initializes it.

MFMessageComposeViewController *controller = [[MFMessageComposeViewController alloc] init];

This line sets the delegate of the object we just made (controller). But why can it do this? Because we have MFMessageComposeViewControllerDelegate set in the iOSBridge.h file. This tells everything in your .mm file "hey if we happen to have a MFMessage object somewhere, it may access delegate properties if you want." [controller setMessageComposeDelegate:self];

if ( [MFMessageComposeViewController canSendText] ) is human readable.

Same with [controller setRecipients:[NSArray arrayWithObjects:nil]]; and [controller setBody:[NSString stringWithFormat:@"Text"]];

But now [self presentViewController:controller animated:YES]; is were we need to dive in.

So in Unity, they said "hey, we don't need to deal with every single possible native function being called" - so they created access to the extern capability for you. This allows you to talk to Objective-C from the UnityScript side of things. Objective-C is just a superset of C, so thats common ground. Everything in here should ONLY call functions in Delegate. The example of this is above in the fake extern.c code block. The only thing that is doing is creating delegateObject and calling a function. Now for the next step. Swap everything in _SMSGO with:

void _SMSGO (const char *mBody) { // I prefer char *name vs char* name but it doesn't matter

    [delegateObject SMS]; // add mBody as a parameter when you're ready. Handle the stringWithUTF8String on the Objective-C side of things. Yes, this is not the Obj-C side, this is the C side.

}

"But wait... you just delegateObject needs to be a thing" - Yes it does. Create another method in your extern "C" section called _init and run this one time from Unity in the Awake or Start function of your class. This will set your static object one time and never mess with it again. Simply make it:

void _init() {
    if ( !delegateObject ) {
        delegateObject = [[Delegate alloc] init];
    }
}

!delegateObject is the same thing as delegateObject == nil but cleaner code. Both say "We don't know what dat is" - Ok now we have our delegateObject, we are free to make our next calls with delegateObject as much as we'd like.

Now when you call [delegateObject SMS] it goes to - (void) SMS. And when you call self presentViewController it knows that self is referring to an iOS Native Object. If you call presentViewController in extern "C" it says "... um, hmm. I haven't got the foggiest notion what that means" - for this reason, we have use everything in your extern "C" section as a crossover to your Delegate object. That is the whole purpose of the extern thing, just to call things in your Obj-C stuff.

Hope this helps.