I have developed an app for the Android and it's working well, finally, and thanks to all the help from StackOverflow!!
Now I am being asked to make it work on the iPhone. I looked at iPhone a while ago but not recently.
What does everyone think? Should I take the time to learn Objective C and iPhone and port the app or forget it?
Are there any books that cross-reference functions so that you can look up how to do something in iPhone that you already have on Android?
From my experience in school, if you have already been able to create a working smartphone app in at least one mobile OS such as android, it wont take long before you can understand objective C and cocoa framework stuff. The only problem with that is you may probably need an apple developer license to use XCode.
So, I would say go for it since you also get paid, and also here is a link to iphone development guide for android developers : http://integratingstuff.com/2011/02/27/starting-iphone-development-as-an-android-developer/
Probably, it's better to get a partner who develop to iOS than doing it yourself.
Focus on a platform and let your products run to all users.
Unless you are using a framework that supports both iOS and Android (something like the Corona SDK) you won't have much actual code that will transfer over. Ideas, algorithms, logic, graphics, designs, etc will all transfer over just fine. Those are the hardest parts (IMO) of software dev.
Objective C (the language iOS apps are written in) is not that hard of a language to learn if you already know C-based languages (like Java). There are a few concepts that are different, but for the most part, it's not that bad. The biggest challenge for developing on iOS is buying a Mac. You can program for Android on Windows or Linux boxes, but iOS apps can only be developed on an Apple. Unless there is something that has happened in the Hacintosh arena that allows for iOS development on other platforms, you're stuck buying new hardware. BUT if you already have a Mac, download XCode and go to town!
Like Haphazard said, if there is enough money in it to make it worth your time, do it.
If you are getting paid, go for it! (Also, it could be a great learning experience.)
When I had to make the same decision, I considered the following criteria:
how much money is in the app on the other platform ?
how many times will this happen in the future, or is this going to be the only app? (how big is the benefit of learning the other platform for the future)
how much insider know-how is in the app that one is willing to reveal to another programmer porting this app (in my case I do mostly device handling apps, which is not really all that common)
what is the opportunity cost of spending time on porting an app instead of developing another profitable on the initial platform
If you have any possibility, you may look into similar apps and see how they are doing on the two platforms...
Good luck, whatever you are going to do...
I just learned about this and have not tested it yet, but one thing that you could do depending on the app you have you could take a look at PhoneGap. It looks pretty promising, though it may not work for your case with your initial application already made. But in the future this could help.
Unfortunately you will either have to re-write the app from scratch for iOS, or hand over the job to an experienced iOS developer. You can fairly easily port over the logic and computations in your app from Java to Objective C, but the user interface is the area where you cannot really re-use anything (except maybe icons), and the user interface tends to be a large portion of most apps.
As an Android developer who has ported several of my apps to iOS, I can say that this transition is a hard one. Firstly, you need to buy an iPhone and a Mac (if you don't already have these), since you cannot develop apps for iOS without the Apple hardware. Secondly, you need to learn how to use XCode and Objective C or Swift. And thirdly, since XCode ONLY allows creating the user interface graphically (as opposed to Android which lets you hand-edit the XML), there are many hidden things which can cause you to come unstuck. (UPDATE: Using the new SwiftUI approach to user interface design really helps with this last point, and in my opinion makes the transition from Android to iOS easier).
Finally the Apple and XCode environments seem rather alien to someone who is used to Windows and Android Studio. There are things like the Home and End keys having completely different behaviors to Windows which is frustrating. Also you have to use a combination of key shortcuts and mouse movements to hook up user interface elements to your code. Also, there are big annoyances such as the pop-up keyboard on iOS not pushing the content out of the way automatically like it does with Android. This is probably because Android is an OS designed for multiple screen sizes, whereas iOS is design for a limited number of screen configurations, but it makes iOS feel inferior and harder to work with from a developers point of view. (UPDATE: Using a ScrollView in SwiftUI solves the keyboard obscuring problem).
Related
Titanium claims it can do the same app on average 70% faster than native XCode.
What's been everyone else's experience in terms of difference in speed of development （between native XCode and PhoneGap or titanium) ?
Let's say an app like Kik Messenger or Badoo ....
Typically, a good XCode developer can do it in 4-5 weeks, assuming graphics and backend are in place.
What would it take for an experienced Titanium (HTML5) person to achieve this? (roughly)
Time to market depends on quality of specifications, process and people, much more than the underlying technology or framework.
Coding a real application with Appcelerator Titanium is not that easy, and runtime performances are SLOWER than native code because it's using a javascript engine as a bridge. Especially with a big TableView, it's much more slower, and the feeling is just not the same. But once you have purged the memory leaks, the feeling is nevertheless incredibly better than with HTML5.
You should be interested in Titanium or PhoneGap(now known as Cordova) if you plan to distribute your application on other devices or if you really don't like Objective C.
If not, keep it with the Native Xcode.
I would add that Cordova will not make any UI, but let you access camera, accelerometer or GPS with javascript inside HTML5 code. You would probably use Sencha Touch or jqueryMobile with Cordova.
In my experience, if the app is not a simple template app then you would be better advised to create a native app for each platform.
As Rob says, trying to overcome the lowest-common denominator situation and overcoming limitations in cross-platform "solutions" usually means it takes longer to code than doing it natively in the first place.
You might even hit a problem which causes you to abandon ship and start from scratch as native apps. So if you decide to go a PhoneGap or Titanium route then make sure you research fully before starting and that you won't have future requirements not covered by them.
If you are an iOS developer and you are developing it only for iOS device, then it is better to code using XCode. If you are more into Javascript and developing for both android and iOS then you should use Titanium or Phonegap. Between Titanium and Phonegap, I found it easier to code using Titanium(and yes fast as well). But I am not sure how much worth is using Titanium. http://usingimho.wordpress.com/2011/06/14/why-you-should-stay-away-from-appcelerators-titanium/
I'm actually performing a fairly intensive survey of all the major cross-platform mobile development kits right now. I started by making a sample application from scratch in IOS that uses a few simple device features, and then reimplemented that as an Adroid app. Both of those took about a day to complete (the android took maybe half a day longer). Since I've never written an android app before, I think that's a good baseline in terms of comparing development time between the various other frameworks I'm testing out.
I'll update this comment in a few weeks with a blog post when I'm done, but for the moment I've been finding that these cross-platform kits are vastly more difficult to use and take a lot more time, even for the simplest applications. and despite this, there's still quite a bit of custom per-device code that has to be written for UI and fundamental idiosyncratic differences between how device services function, so you don't really get the value of a true "single code base" that you may have been expecting.
I think the main value in these may turn out not to be anything related to development time or code reuse, but instead only as a way for non-app-developers to create simple prototypes that can later be handed over to the "real" mobile developers to be built out into true native apps afterwards... Not really all that useful in my opinion, but maybe my thoughts will change as I delve into this further.
Appcelerator is not HTML5, it is a native app built in a higher level language of JavaScript. It abstracts the complexity of common elements away and provides huge value, ping me offline to know more. I run our California business.
I am a C Sharp.NET & Silverlight developer and now thinking to swicth to SmartDevice development specially for iPhone & Andriod based phones. I have looked over web and found some cross platform development frameworks like
http://developer.openplug.com
http://www.phonegap.com/
http://android.xamarin.com/Welcome
but not sure about which to choose. Naturally I would like to keep my learning curve less but also would like to choose platform which provides more power, so I am looking for your suggestions and 'Getting Started' tips and also which device you think will be in demand in future iPhone or Android ? .
Thanks,
Maverick
I wouldn't recommend any of those. The problem is, that those "cross-platform" development frameworks, still aren't cross-compilable. This means you still need to develop an application for each platform, but you can reuse heavy calculations if you are using models af MVC.
Another thing is that those frameworks still aren't 100% native supported, so you'll loose some features from the native frameworks when developing applications.
I've read a lot of articles and to be honest, these cross-platforms seems to be dying out, cause both Android and iOS are moving very fast in each their direction and the cross-platforms cant keep up. But it's still up to you.
In would recommend you to choose one of those platform and learn it from scratch. With your C Sharp background, maybe iOS and Objective-C would be the most natural choice.
Enjoy
Edit: Regarding you last question:
I dont think it matters which one you choose, both will be domination for a long time. You should pick the one you can identify yourself with.
since you are C# dev, go for MonoTouch. I heard good things about it.
Miguel de Icaza is behind Xamrin. He wrote the most prolific .NET platform for UNIX, mono. I believe both he and his team have the capacity to bring you the most coverage for common features on Droid and iOS. My friend has a startup and is releasing an app shortly for iOS on Xamrin. It is a video streaming app.
HTML 5 will get you the most cross platform for the investment. Of course, like everyone else has said, if you need lots of native integration or if you want to use the latest APIs upon availability, you have to go native.
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I want to build a mobile/tablet application whose core feature will be taking pictures with the camera , viewing pictures and receiving notifications. Also I want to target iphone, ipad and android platforms.
Titanium appcelerator piqued my interest because of its cross platform appeal. However I am concerned because I've read mixed reviews on SO and other sites. The things that worry me are:
Subpar android support
Camera support not fully capable (e.g ios 4.1 HDR capability)
Camera support buggy
The nightmare scenario for me would be to invest time in titanium only to discover later on that its a major PITA and drop it and go "native"
Please share your thoughts and experiences.
I chose Titanium for a serious application, although one that does not use the camera. I think there are a variety of things that could play into your decision...
If your app intends to do "fancy" stuff with the camera, or some real heavy image processing and so on, you're likely better off going native. If on the other hand, you just want to have it take pictures, and then those will be used as-is, or sent to a server, or what not, then Titanium should work just fine. Titanium does have some processing and image manipulation things, but as others have said, if you really want to take advantage of the device's hardware, you probably want to go full native.
It should also be noted, and Appcelerator says this as well, that with a Titanium app, you won't just write a single app that works as-is on all devices. You will need to taylor the UI to each device (or class of device, i.e. iPhone, Android), because they have different UI's, and different standard UI flows and so on.
But, one of the potential advantages to Titanium is if you don't know Objective-C and/or Java, and you do know JavaScript (and in my case, I'm actually using Coffeescript :). Or, if you would enjoy your work much more writing JS than ObjC/Java. This was one of the main reasons for me. I have done some ObjC dev in the past, and don't even mind it, but this project I'm doing is on a very very aggressive schedule, and it was just going to be far more effective for me to use Titanium. I was able to get set up and build an app extremely quickly, and I am not spending any time having to become more deeply familiar with the programming language I'm using, memory management bits (you can't fully ignore this with Titanium, but essentially they're doing it for you). Based on the folks I've talked to, and how much time they spend with memory management, Interface Builder issues (this is mostly the ease of forgetting to setup connections or hook various things up, IB is actually a pretty great tool), and so on, I'm quite glad I'm using Titanium.
While I expect to do an Android version at some point, it's not a priority. But, I'm glad to know that a large chunk of my app code will be re-usable, tested, etc. and that I'll wind up mostly just building/revamping the UI for Android, not rewriting networking code, data management, and so on. Android support will be much better (supposedly) in Titanium 1.5, but you may want to wait for that release to evaluate Android if that's a priority.
Finally, Titanium does have a "module" system, that allows you to wrap native code, exposing it as a JavaScript interface in Titanium. We are about to leverage this to integrate a third party library, and at least for what we need, it looks very easy to use, and has given me a little more confidence that if some particular native feature we need access to comes up, that we'd have a decent chance of integrating that while still using Titanium, but I think it would depend on what the particular native functionality was.
Good luck and enjoy building a mobile app, it's pretty fun!
We have been using Titanium in one of our projects for around 2 months, and frankly speaking our experience with Titanium is too bad.
As per my opinion, below are some major drawbacks of Titanium:
1) First thing is you will not get debugging support at all (We can understand how debugging require in any of the project and in any of the technologies).
2) Titanium is NOT fully supporting all the features of Android/iPhone; beyond some level it will not give you support.
3) Comparing with Android/iPhone SDK, developers will get very less amount of help from the internet and API library (Titanium provides the API library help file).
These are the general issues that end developers face while dealing with Titanium and I suppose sometimes it will be tedious and frustrating work for them.
If the functionality of your application is somewhat like displaying data from the web (like many news, media type apps) then Titanium is the suitable option; otherwise not.
The Android support is not near as good as it is for the iPhone. If you were to just say iPhone I would say you would have luck using Titanium. However, I think trying to build one code base in Appcelerator and also use in your Android environment may not be the best experience.
That said, IMO doing Android / Java code is much easier than doing Objective C / iPhone work.
So worst case I would consider using Titanium for your iPhone version & do Android in Java.
You can give it a shot doing them both in Titanium, but worst case code the Java version.
I just hate objective C and the 'native' Apple development environment so much.
I would recommend against using a cross-platform toolkit when interacting with device hardware is one of the key requirements of your application. I haven't worked with Titanium before, but I find it hard to believe that they will give you the same level of hardware access that you get with native frameworks.
In particular, iOS 4.0 added a mess of new capabilities regarding the camera, including live video frame processing through AVFoundation, and I find it hard to believe that a third-party framework will keep up as these platforms advance. To be honest, it's pretty easy to write an application that interacts with the camera on the iPhone nowadays (count the number of them on the App Store as an indicator of this). I wrote a live camera frame processing application in about six hours the other day.
I can't speak for Android, but I imagine dealing with cameras is fairly trivial using the native APIs there as well.
You're also going to find performance testing and debugging your application to be far easier using the native tools than those supplied through a third party. In particular, Apple's Instruments is an extremely powerful, yet easy to work with, application for tracking down CPU and memory issues within your application.
There's also the community aspect. You'll find far, far more people working on Android and Cocoa Touch than on Titanium (just look at the numbers of questions in the various tags on Stack Overflow to see that). This means many more tutorials and a whole lot more sample code that you can use.
The time you'll spend getting your iPhone and Android build environments set up, and submitting to both stores, will be the same no matter if you go with a native environment or with Titanium.
In the end, even with learning both platforms, I think you'll come out ahead by avoiding a cross-platform solution. Trust me, I've tried to do cross-platform development before for other projects and ended up with lowest-common-denominator products that took much longer to write.
I've developed an Appcelerator-based camera application and was very pleased with it. I think some of the negative reviews come from the fact that it's a bit hard to get set up (more due to Apple's crazy developer registration process).
Once I got started, it was easy to do things like overlays on top of the camera screen. I was really expecting difficulty with that part, but it worked well.
I have spoken with the Appcelerator team in the past, and they are a great group to work with. I've seen them be responsive to other user issues, and I'd trust that if I ran across a real bug, they would address it quickly.
A little late, but my two cents...
I honestly believe you can very quickly prototype an application with Titanium Appcelerator and focus on the critical feature sets to determine if it is the appropriate tool for you.
All developers have there opinions and experience(s) which influence there comments; developers have different ways of learning and different levels of productivity... In the end, it comes down to how are you most productive with the tools available to you.
Since you are stating from the start that you want to deliver a solution an multiple platforms, I think it would be a poor decision on your part to not even spend a week or two investigating cross-platform frameworks and then making the decision based on your personal experience.
There is Titanium Appcelerator and there is also PhoneGap, where PhoneGap might help you is that there is the ability to extend/enhance the underlying framework through writing plugins (I wrote one for iphone ) and there is an android one on my blog also... this can fill missing gaps for you when you move across platforms.
Also since the UI in a phone gap solution is HTML5 Webkit based, it can give you a consistent look and feel across you devices if you like. Frameworks like jQTouch and JQuery Mobile are being used for UX with PhoneGap Application
I reviewed negative feedback for Titanium Appcelerator but I tottaly agree with Aaron Saunders that if you use PhongeGap Development is support HTML5 which can getting easy to make apps for iPhone, iPad and Android mobile.
Has anyone highlighted the cost off titanium.
I was contacted by them today and if you are more than a one man band you have to sign up for a partnership program else you are held liable for breech of contract if you release the app.
The partnership program is £5000 which is far to much for us as a start up company when it's our first application, we are currently looking for a different option now.
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I'd like to start developing for iPhone or Android in my spare time, as a chance to learn something new but also hoping make some extra income.
I'm not sure which is the best development for me to start developing on. I own an iPhone, but I don't have a Mac (which I would need to use the SDK), plus with the iPhone I believe there's an annual charge to develop for it.
As far as I understand Android, the SDK is free and can be used on Windows.
Professionally I develop using .net and C#, which sounds more similar to the Java based Android enviroment.
Another negative I perceive against iPhone is it has a much more crowded App Store, I would think apps get better exposure on Android?
Both can be good/bad for various reasons.
iPhone - good
Great SDK & get to use Xcode which rocks
Well documented online (many tutorials)
Large deployed base of devices
Well established app store
Get to learn Objective (I find it a fun language)
Most people tend to upgrade their iPhone OS so you can get away with only developing for the latest and greatest
iPhone - bad
Crowded app store, very hard to break through (the "gold mine" is a myth)
App Store apps need to be approved by Apple, with some often rejected for dubious reasons
Have to buy a Mac (not necessarily a bad thing)
Have to learn Objective C (can be a hassle)
Have to pay $99/year to publish apps
Can only multitask on iPhone 4.0+. Hardware restrictions will mean many devices will not be able to use this however
Android - good
No restrictions on apps that you can develop/publish
Wide deployment of devices and growing - set to overtake iPhone soon
Can multitask on Android
Get to code in Java which is widely known
Some of the SDK tools integration with Eclipse is nice (although still needs a bit more work)
Only have to pay $25 to publish apps (one off fee)
Can develop on any platform (Mac/Windows/Linux)
Great Android devices coming out this year - platform could really take off.
Nice XML way of laying out views. While not as flash-looking as the iPhone Interface Builder, it is very powerful.
Get to work in Eclipse (which some people think rocks)
Android - bad
Have to support wide variety of screen sizes and devices
Many people still using old versions of Android OS (1.5) so you'll probably have to support those if you want to reach that market
SDK is not as polished as iPhone SDK
Android Market is not as popular as iPhone App Store - hit apps will not make as much $$$
All in all, starting with whichever is fine in my opinion, especially as now Android is gaining ground. Given your background I'd say you should go for Android.
In my honest opinion - I see the recent changes in iPhone SDK a kick in the teeth. I'm an Adobe person and you would assume, an infinite number of developers begin building applications in CS5 would be great for you App Store? Apparently Apple do not agree.
However - if your looking for exposure, getting an App into the App Store will yield more results if you build a quality app. As the Android store hasn't got a footing yet (if they'll ever be one), all marketing is on your own head.
I recently defunct Apple as they force us developers to 'be them' and I don't agree with their ethos.
That said, having programmed for both, The Android is slightly tricker to get installed and took a very long time to sort itself out. Although the instructions are very good and the examples are well defined.
If you've got a mac, installing the iPhone SDK is a sinch and you ready to build apps. It does cost £50 for the developer connection and yes android is free. [Correction - this may cost a one of fee of $25]
If you are building an iPhone app thats heading for the wild, you will need the connection (this can take up to 3 weeks in my experience) so you can test it on your iPhone.
And you'll definitely need to purchase a Mac.
--
With Android, its java, and with the newest rendition, a very good API to work with. As an additional bonus its build upon Eclipse, so it'll take you seconds to understand whats going on.
--
As a final thought - being an Actionscript/JS developer, the transition to Java was a logical and simple step and (please don't shoot me if you don't agree) Objective C is a train wreck of two different language styles. I found it very very difficult.
but don't just take my word for it, definitely try them both, as I see Android emerging market just an ice berg right now, but Apples is established.
Two disadvantages of iPhone/iPad apps ecosystem are:
Apple test & accept apps before puts them into AppStore (this take time and acceptance depends on Apple current policy) -- Google seem not to care about that so much.
AppStore it's the only official place for iPhone apps -- on Android you can install apps from unsafe source (i.e. website or email attachment) -- so you can provide and charge for app in various ways.
You say you want to (a) learn something new and (b) make some extra income.
As far as (a) goes, your barriers to entry with Android are probably lower. You can develop on Windows, Linux, or Mac; the sdk is free, and there are no charges. Android development is usually done in Java, which is not that different to the c# you already know. So, I'd say get Reto Maier's book and give Android a try. At some point you'll need an Android phone, but you can get some way using the emulator. You won't have to buy a mac or pay for a developer licence.
Once you're familiar with developing for a mobile platform you'll have a better idea of what it takes to build apps that other people will want to use, and maybe even pay for. At that point you can evaluate the platforms from the point-of-view of (b) and decide which one to pursue. If you end-up buying a mac and paying for a development licence then at least you'll be making an informed decision. But get some experience first.
Like you, I'm a c# dev. I've done some Android development for my own amusement, and (for what its worth) my personal opinion is that its a superior platform in comparison to the iphone because it is more open (technologically and commercially). I believe Android will fairly soon either achieve partity with, or even overtake, the iphone.
Try Android, get some mobile experience, then decide.
MonoDroid for Android is in beta, which means you'll be able to write Android apps with C#. You can sign up for the beta here.
iPhones are getting more and more restrictive. Android is opening up. Android is also shipping more phones than iPhone. You decide.
take a look at this book , it's a good reference to decide the 3th way... HTML, javascript & CSS for iPhone and Android at same time, based on webkit, using jQTouch and
PhoneGap . You can see on the first chapter the pros and cons.
I would suggest getting your hands on the latest iPhone SDK and a Mac from a friend before taking the plunge unless the $600 minimum investment for a macmini(what I did in my case) doesn't bother you.
You could try installing GNUstep for Windows and messing with Objective-C without buying a Mac to check out the language but it's not the same without XCode and Interface Builder,SDK,etc.
The reason I say this is because I'm currently taking an iPhone class and just learning Objective-C is a lot larger learning curve than I thought it would be and eating up a lot more of my time than I cared for.
Unlike C# or Java you have to manually keep track of memory management which is really annoying and a hassle not to mention Cocoa Touch, which is sort of like .Net or Java classes for Objective-C; another big learning curve! Bottom line neglecting the fact that it is a mix of SmallTalk and C and looks horrible if you can get over that it is still hard and easy to crash your program.
Forget to hook up your outlooks correctly in Inteface Builder?
CRASH!
Forget to use an # for an NSSTring due to the loose type checking?
CRASH!
I'm just saying that you'd probably be more productive and actually get applications completed in your spare time going the Android more familiar Java language route vs the Apple route. Also, I'm not sure how big Android is on the whole MVC concept, but it's everywhere in the iPhone SDK since Cocoa uses the Model-View-Controller (MVC) design pattern throughout.
On the other hand, if you like a challenge or learning the Apple route is the way to go and if you are good you app will sell and you will make money. Like I said there is a ton to learn with the iPhone before you can even start thinking of selling the next killer app LOL.
p.s. Oh and unless you want to test something on actual hardware that doesn't work in the iPhone/iPad simulator or actually upload an app to the store you don't need to pay the $99 fee to develop.
If you're a C# developer, and you're looking to begin iOS development, then you owe it to yourself to read Josh Smith's iOS Programming for .NET Developers.
It's exactly what you're looking for.
Is there any MacOS virtual machine that can run on PC?
Is there any source to get it?
What is the best way to develop apps for iphone?
Yes all the developer tools are OSX only.
There are lots of iPhone development books out there go check out amazon and find one with some good reviews and that will get you started.
You might not, in the strictest terms, have to get a Mac to develop for iPhone; but it will be extremely helpful. Apple is relatively talented at squashing efforts directed towards Hackintoshes and virtual machines running OS X.
The shortest answer that will give you the least hassle is: Yes you need a Mac.
But, as far as I know there are a few possibilites, that try to reimplement some Cocoa Frameworks (however they might be Mac OS X only and not iPhone): GNUStep is an example.
But I don't think you get something aquivalent to Xcode (the IDE for iPhone development) this way.
And I think there are some OSX86 Virtual Machines (however these seem to be against Apple's EULA and thus seem to be clearly illegal so I won't point you anywhere to get them).
So to conclude - if you want to develop for iPhone: getting a Mac is the easiest way, even though not cheap.
Hope this helps.
The short answer is - yes.
One possibility for learning some of what you need to know before getting a Mac is GNUstep.
However, GNUstep is mainly useful for learning Objective C, especially since it provides many of the classes that the Cocoa toolkit for iPhone does. This can be run on Windows.
It doesn't, however, support some of the key 2.0 language features that are used 'all the time' in any sample code.
What it will allow you to do is design a UI using their UI designer GORM, and use a near-identical message-based system for implementing a UI, and you could theoretically write Objective C classes in GNUstep and then use them on iPhone.
However, to compile an app for iPhone you basically need to have a Mac, because then you can get the key for signing an app, etc. Since you need to get a Mac at some point, there's really little point in going the much harder route of using GNUstep first and learning a more limited implementation, unless you really need to get started before funds are available.
Despite the new SDK terms that can other programming languages, if you're really wanting to start without a Mac, I'd probably be tempted to look at something like Unity, or perhaps even Appcelerator Titanium, and figuring out all the non-platform-specific logic first on whatever platform (Unity has a free version that can be run on Windows, for example).
I'm not that big a fan of xcode, but is is far and a way the best IDE for Objective C development simply because there's almost nothing else out there.
There are, as always, other options. If you do a web app type project, you can implement the website and test a lot of it in a browser. Furthermore, since Android and iPhone browsers are both WebKit based, you can use the free Android SDK to see what pages look like on a comparable mobile device. And since you can use C and C++ classes as well as Objective C (N.B. not for the GUI, since that needs the Objective C extensions for messaging between objects), another option for making a start without a Mac would be to use Eclipse, QT Creator or some other C/C++ IDE to implement non-GUI classes, so long as you make sure you don't use platform-specific libraries.
But the end of the long answer is still that whatever you do, to compile a proper iPhone app you'll be using xcode and associated tools to finally build it and sign it, and so you need a Mac in the end. If you want to create something targetting the iPhone and won't have access to a Mac, then perhaps you're best off looking at creating an iPhone-adapted website using iui or a similar toolkit to give the site a suitable look and feel.