Tag Archives: objectiveC

iOS notifications from developer's view

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Notifications in iOS devices such as iPhone and iPad are a way to tell the user about some important thing has happened. From a users perspective it is just a message reminding thing.
For a developer, one must note the difference between the type of notifications. Well, to be at its simplest form, there re two kinds of notifications. One is local notification and one is push notification (think this as server is telling the iOS device to show the notification).
Well, why should I bother about these two as a developer ?! That might be the question if you are doing the notification programming in iOS for the first time. The answer is, iOS gives very certain instructions as to what and how to do the notification implementation.
Here is the official link to the Apple documentation.

There are only three types of UX for either of the notification (local or push). They are
1. Displaying an alert message
2. Badge the application icon
3. Play a sound

The settings to control these notification types are located in the global settings menu of iOS. Remember it, the settings of all the applications, which use notifications are at one place in all iOS devices and that is the “settings” menu.
Well, another subtle but important option is “notification center”. Its the place, where all the notifications from all the applications reside. The settings, whether to keep the “notification” in “notification center” or not is also inside the global “settings” menu. Being a developer, the good thing about Apple and for that matter the iOS is, one does not code for adding settings item for notifications. It is done automatically for you by the OS (Operating System). All this magic happens, when you as a developer, makes a “certificate” for the application in Apple developer’s portal for the application saying “this application used notification”. Simple and elegant.

The major difference from developer’s point, between local notification and push notification is local notification is scheduled. That means, we can not show a notification if certain things happen in the application. Once application goes to background, we lost power as a developer to do anything at all with that application. So local notifications can only be scheduled for a normal application (for music streaming applications we do get a little more control). If at all we have to notify the user on certain data change, we have to fall back to push notifications. This one is pushed by Apple Push Notification server. Though, there are third party services which can push data, but all of the data push to an users device route through Apple Push Notification server.
The last thing to note is Push notifications are created on the server and pushed to the device, at max, upon tapping the notification, the underlying application can be brought to foreground and thats all one can do as a developer.

Tips for phonegap developers :
1. There are two different official plugins (one for local and one push notification), but then these plugins are not always up to date or might not support your version of the phonegap(cordova), do some reading before you settle down with the plugins.
2. The third party service providers (for push notification) might have their own plugins (a lot of do have), its better to use their plugins if you are developing upon their infrastructure.

Tip for push notification :
Make sure you are creating proper certificate with “push notification service” enabled at “Apple developer portal” and then using a profile on XCode which uses that certificate.

Some push notification servers are
1. http://www.pushwoosh.com
2. http://www.xtify.com
3. https://pushwizard.com

Would like to know if anything I am missing here, I am putting things here as I am doing hands-on with this iOS “notifications” for the first time.

Sparrow V1.2 is released

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This is one of the most stable releases of Sparrow framework, as it is said from its creators. This is very exciting news as there are some very subtle but significant changes happened. One of the features, which I like most is, the position of the pivot point of a texture. Previously one need to put it inside a container, now its just a property setting.
The complete list of updates could be found in its officials blog here.

Posted from WordPress for Android through my “HTC Wildfire”.

Lua : My experience with it.

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Well, on my journey with mobile development, I picked up Lua for sometime. I am quite impressed with its simplicity and power. If you do not know, Corona SDK provides Lua scripting language to build applications for mobile devices. The popular Angrybirds game utilises the power of Lua.
Basically its a simple language with very minimum number of key words and language syntaxes. Anyone familiar with javascript or actionscript can start jumping into it and be productive from day one. There are variants of the installer for Mac and Windows. Some what I feel Windows installer is the best and has got its own IDE, which is on top of popular SciTE IDE.
There is a complete 2D game engine / framework for Lua named Love. With that one can instantly start creating Lua games. As Lua is simple, so as Love is. But then one gets a whole lot of goodies out of a framework. I would say a must try for any game developer.
There is a nice framework for iPhone, which uses Lua and its called WAX. This also fits Lua’s philosophy as to keep the framework simple and easy. The best part is, once you start coding in WAX, you do not have to think about memory management, which is very important and sometimes most time consuming act, while developing application with ObjectiveC.
Now that I have seen Lua’s power and simplicity, I will try that out more and more and post updates about my experiments. Here are some Lua related links for you to get used to
1. Users, tutorials and more
2. Love : 2D game engine
3. WAX : iOS development framework
4. 2D Engine A 2D game engine (I Have not tried yet)
5. Luxinia 3D game engine (I have not tried yet)
6. Lua Forge Projects, tutorials and more
7. Baja Engine A game engine (I have not tried yet)

With that I think I also have to pick up some engines and start playing with it. Overall, Lua feels just perfect as its simplicity and power. Its portable and lightweight. After all its Opensource and Free.

My second iphone game

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CatchThemAllV0.1.0

Just finished my second iphone game. While I have not tested it on device yet!!

My first iphone game was taking the accelerometer into game play and this game is all about multi-touch. While it is quite straight forward to play, but it holds the ability of being engaging and addictive.

The game play is to choose the color which is displayed maximum times on screen. There are only 5 colours, but then one has to count the number of times. There is a simple counter runs to show how much time one is spending in a particular question. If the counter reaches 1000, the question changes to the next question and the player looses one point. The interesting part of the same is, each of the colours is assigned a different touch input. That means, if the player has to choose a particular colour, he/she may have to touch with 3 fingers, similarly there are 2 finger touch, 4 finger touch etc are available.
The game play is going to be interesting if you are trying out in device, on the simulator, its a waste and boring thing.
Hope, I will test it soon with a real device and come up with my first experience with it.

Code is hosted at Github and the direct location is here.

Happy Gaming :)

Making random numbers in ObjectiveC, the quick and dirty way.

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This is another part of my iphone development experience, where I really feel the pain over and again. So putting up my quick way to do get a random number. There are a lot of methods regarding the random number generation in objectiveC and there are even third party attempts to get the best random number possible.
The three most obvious functions are rand(),random() and arc4random(). While a lot can be heard around of not getting a random number by the first two functions, the last options is better. At least I get decent random numbers with it.
Now to get a random number between 2 points, the code would be

//random number between 0 and 5 not 5, till 4
int i=arc4random()%5;
//random number between 10 and 15 not 15, till 14
int j=10 + arc4random()%5;

Hope that makes my next random number creation search leads me to look at this post.
Happy coding :)

Dealing with Touch Events, the Sparrow way.

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This is specifically caught me, when I am coming from other object oriented technology. May be because of those environments are all single touch based. And I never have worked in multi-touch based application.
While working in Sparrow-framework, there is a nice event called “SP_EVENT_TYPE_TOUCH” . This is basically used if we want to use the touch based interaction in our game. Once we add an handler to it, the general expectation is it will just fire up once per touch/tap. But actually it will fire up 2 times as we have 2 different events, “touchesBegan” and “touchesEnded” for each touch interaction in the main cocoa/objectiveC framework. And the good news is Sparrow-framework does a nice job of encapsulating the internals of all those two events and gives us one event to deal with, that is “SP_EVENT_TYPE_TOUCH”.
Well, but the catch is getting confused with the event handler code. Lets dive in here.

[self addEventListener:@selector(onUserTouch:) 
	atObject:self forType:SP_EVENT_TYPE_TOUCH];

Now the handler code will look as below

- (void)onUserTouch:(SPTouchEvent*)event
{
        NSLog(@"onUserTouch");
}

When run, this code will generate log messages two times for a single touch! Thats for the reason we discussed earlier. Well, the fix is on the handler. We have to deal the events inside if-else where we will check, whether its single or multi touch as below.

- (void)onUserTouch:(SPTouchEvent*)event
{
        NSLog(@"onUserTouch");
        NSArray *touches = [[event touchesWithTarget:self 
                       andPhase:SPTouchPhaseBegan] allObjects];
	if (touches.count==1) {
		NSLog(@"1 fingure touch ");
               //Do the custom code here for single touch events
	}else if (touches.count==2) {
		NSLog(@"2 fingure touch ");
	}
}

For only single touch the syntax is even smaller

- (void)onUserTouch:(SPTouchEvent*)event
 {
     SPTouch *touch = [[event touchesWithTarget:self 
                 andPhase:SPTouchPhaseBegan] anyObject];
     if (touch)
     {
         SPPoint *touchPosition = [touch locationInSpace:self];
         NSLog(@"Touched position (%f, %f)", 
              touchPosition.x, touchPosition.y);
     }
 }

The only difference being, while handling single touches we can directly use “anyObject” as the last parameter and that will give us a single event and for multi-touch environments we have to use “allObjects” as the last parameter. But all this will happen inside the event handler, which will by default fire up twice.
One has to get the “touch” or “touches” inside the event handler and then process the code according to it. Directly the handler will fire up twice and that must not confuse as to, whats happening around!

Happy coding :)

Category and Inheritance on ObjectiveC

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While Category is a nice way to add functionality to the base class, people like me who come from other object oriented technology such as Flash, will find a little difficult to understand as to how this thing relates to the inheritance chain. The same question came up to my mind and I did a quick research on the topic.

The final thing is Category does the same thing as it tells about itself. It adds functionality to the base class. If you remember this, then there would be no confusion at all.

Well, for that to understand, lets take an example. Suppose there is a Class A and Class B is a subclass of Class A. In the application Class B is used in a lot of places. Now, there is a need to add some more functionality to Class A, so a new category is written as “A+newRole”. Once this category is written, the new functionality is added to the base class and in this case, Class A. That means, all those classes which are child classes of Class A such as Class B, automatically gets the functionality. Thats freaking cool. One can straight away go ahead and call the new methods added in the Category from the child classes. The only thing necessary here is to import the Category file to the appropriate place.

Tested my first iphone game on device

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MathIsFun2
I feel so happy to get my opensource game tested on some real devices. The game got tested with iphone3GS, iphone4 and ipodtouch2G. Thanks to all my friends to help me with this. You all rock. And with that I come to a point where may be this game is pushed to Appstore. The tests were good and made some changes as per the retina display of new iPhone4.
Overall it is nice experience to see my game on device.
Cheers to life.

My first iphone game goes opensource

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I have recently finished an iphone game. This is written in Sparrow framework. I have decided to make it opensource and so put it up on github at this link. The game is very simple and is licensed under Unlicense. So there is no restriction as to how to use the code. You can use it to make money or what so ever as this licensing does not force you to do anything you do not need to do.
About the game, its a simple game of Mathematics for small kids. There are options for addition, subtraction, multiplication and division. Choose your type to play and go ahead playing it. There is no score, no time limit. The responses are immediate. So one will know whether correct or incorrect answer.
While I am developing on it too. Will love to see what others can do with it. This can be seen as code example for the Sparrow framework as well.