I'm designing an iPhone application and writing a paper on it. I was wondering how I can see how much virtual/real memory my application will take in the iPhone. I am currently running it in the simulator.
No, this cannot be done accurately. You can get consistently good values for most of the APIs you use using the Allocations instrument, but there are differences in execution environments which make exact figures impossible.
Yes, you want to Profile you app. In Xcode, hold down the "Run" button and select Profile. A window should pop up asking you to select an Instrument to profile your app with. For memory usage, you can analyze your apps using either Allocations or Leaks. I would do some googling for instructions on how to use these two instruments.
I've tested my app thoroughly on the simulator, but I don't have an iphone/ipad/ipod touch on which to test the app. Are there likely to be bugs that dont expose themselves until I test it on the device?
if i had a macbook, id take my code along with me and meet up with a friend or a stranger to test the app, but im working with a mac mini :(
Thanks for the input.
The one major concern is performance. Devices, especially older ones, have orders of magnitude worse performance than Mac mini, both in terms of CPU and memory. It is possible that your app is crazy slow on a device, yet runs fine in simulator.
Other areas to think about:
network connectivity, performance in poor/no network conditions (good way to test in simulator: yank out ethernet/turn off airport... but some reachability code works differently in device and simulator I think, and you cannot simulate mobile-only [no wifi] situation)
As Rengers said, you should get your friends' device IDs and then create a provisioning profile so they can run the test version of your app which you can e.g just zip up and email to them.
You will really want to pick up a device, an iPod Touch isn't that expensive, and you can even get iPhone 3GSs for less than $100 now at some retailers (contract required). The reason for this is that there have been many cases of the simulator doing one thing while a device does another, in addition to the resource differences (both in terms of available cpu time and memory)
Yes, there are bugs that will only show on the device. It depends on the complexity of your app. For a fairly simple application, chances a bug will show up on the device only will be a little lower.
However, I strongly recommend to test on the device. Bugs aside, you can't get a good measure of performance on the simulator. A real devices has much tighter ram and cpu constraints.
If you have a developers account, afaik you can distribute apps to testers. Perhaps someone else with an 'iDevice' is willing to test for you?
I've had lots of problems getting a simple UIImagePicker working (see my other posts), and I've been getting memory warning notifications after taking a picture and before I even get a chance to dismiss the UIImagePicker
Now, however... I've loaded up my app in Xcode today and all is working fine. Can't get the memory warning at all, under the same build settings etc.
My question is.. is this normal? Perhaps it was cleared by an iPhone restart, or XCode restart. Or should I be worried that I've still got a hidden memory warning, only now it's hiding from me?
Thanks!
yes, very normal. memory is used by lots of background tasks on the phone, so it really depends what your email client is doing, whether you're installing apps in the background, and lots more.
It also depends a lot on the device you're testing on too. For example, if you're testing on an iPhone 2G, you'll have a significantly lower amount of memory to play with than if you were testing on a 3GS for example.
Depending on what kind of requirements your app has, and what choices you're making in terms of what to target (3.0 only? 3G upwards, etc) its best to always test on the least capable device so that you can get an accurate idea of how the app will perform on that device.
I know there are emulators, but is this good enough? If someone is serious about iPhone development, do they absolutely need an iPhone?
Just my personal opinion: if you're serious it means that you're committed to quality of your product. If you're committed to quality there is no way to deliver a product without actually launching it on the target platform :)
As noted in other posts you'll have tough time testing the multi-touch screen and other aspects of the hardware on your emulator.
Don't forget that most types of iPhone apps also work on the iPod Touch, which is a one time cost and no monthly fees. Even network apps work if the iPod Touch is connected to WiFi.
During development of my first iPhone app, I wrote code that worked fine on the iPhone Simulator, but which did not work on the device. So I would say "Yes, you definitely need to test on an actual device."
The simulator is not an emulator. It is not running the actual iPhone OS; it is running a set of Mac OS X libraries that are very similar, but not identical, to iPhone OS. The simulator is great for debugging and saving time during the code-and-test cycle, so you will use it a lot more than the device, but a device is indispensible.
You really do need to touch-and-feel your app on a real device. A UI that works great while pointing and clicking with a mouse might be terrible when used with thumbs and fingers. If there is any text entry, you need to feel how painful it is to type using the onscreen keyboard, to determine whether it makes sense to provide alternative data-entry methods.
There are also significant performance differences between the simulator and actual devices. You need to test with the oldest (slowest) device you want to support to verify it is not too slow, doesn't run out of memory, etc.
As others have suggested, an iPod Touch is also sufficient, so the cost of a device isn't huge. Also, try to find beta testers with a variety of different models.
Necessary: How the app handles in your hands is critical to something like the iPhone. you cannot tell how it will feel to use when plastered straight in front of you in the emulator on a big screen.
If you cannot hold it you won't be getting the true user experience.
If you need to learn Obj-C, go with the emulator for a while until you learn the ropes and save the expense for later. But yes, eventually you will need an iPhone for final testing. How long you can wait will depend on the features that your app uses, If all you are doing is button presses, you can wait a long time. If you are dragging, using location services, etc., you'll need a device earlier in the development cycle.
Are you trying to convince yourself or your boss? ;-)
I'd say you need one. Emulation of such a new device can only go wrong. Plus don't forget the tactile aspects.
The iPod touch is a reasonable substitute provided you are not using:
GPS, BlueTouch or Camera - the iPod touch doesn't have these
Cellular network - although the iPod touch has WiFi, the latency of a cellular network is way way higher than that of a wifi network. If you are doing anything like designing a custom protocol for your application, you will want to check real-world performance - and if you do this too late in the development cycle, you will be in for an unpleasant surprise.
Whether you develop on the iPod touch or on the iPhone, you absolutely must have a device. This is not optional! The simulator is good, but it is not perfect, and there is no substitute for having a device which correctly indicates performance, screen resolution, brightness, form factor and all the other factors that you will need to consider in your application.
If you buy an iPod touch, you will probably end up getting an iPhone too. I'd just go straight for the iPhone. That way you can use it as your main phone, and get a real feel for how the platform behaves and what an application needs to do to make it great.
Kind-of "yes".
Just download iPhone SDK (it's easy and free) and check out the emulator that is in there. You'll see whether that suits your needs or not. The emulator is not indicative of real hardware performance, there's no touch input, some quirks might be different, some things can not work, etc.
The iPhone Simulator makes it easy to test your applications using the power and convenience of your desktop or laptop computer. Although, your development computer may not simulate complicated touch events, such as multifinger touches, the Simulator lets you perform pinches. To perform a pinch, hold Option while tapping on the Simulator screen.
I'd say it depends on the kind of application you are developing. For a successful iPhone app, one which is properly integrated on the system, you are going to need to be able to test your tactile interface. That's hardly accomplished with the Emulator.
So, my answer is Yes, you do need an iPhone to develop iPhone apps. Fortunately, if you cannot afford one, an iPod Touch (200 bucks) is a very competent replacement. The underlying hardware is pretty much the same.
Necessary. If you plan to develop a successful product it needs to be one the end users (not just the developers) find easy to use.
The best way to do that would be to load your app on an iPhone then take it to various people and ask them to use it while you watch them to see if they experience any issues.
Users can get mighty creative in trying to do things a developer never intended - just ask any support tech.
Unless you're app is going to sell for less then $500 total it's a relatively small investment to build a quality app.
If you are serious about development, an iPhone (or iPod touch) is a must. However, the official SDK comes with a very complete "iPhone simulator". This will allow you getting a feel for Objective C and the entire development workflow. The SDK requires Leopard.
You don't need a Mac for this. You can use OSX86 on your PC, either installed on and booted from disk or through VmWare.
It works. In fact, you can even synch the iPhone through Leopard running in vmWare.
Now, testing on a real iPhone is a necessity because of performance, memory usage etc. Also you need it for the entire authentification procedure, getting the keys etc. (if you want to sell your stuff on the Appstore), testing this really requires an iPhone.
If you buy an iPod touch, you will
probably end up getting an iPhone too.
I'd just go straight for the iPhone.
That way you can use it as your main
phone, and get a real feel for how the
platform behaves and what an
application needs to do to make it
great.
I absolutely agree with this.
If you are seriously developing an iPhone application - for fun or for profit - you will have to run it on a real iPhone to test out compatibility and usability at some point. Since you going to have to get one at some point, you may as well get one now. Don't go for half measures. An iPod Touch may be [significantly] cheaper to start with, but will be money wasted when you go and get your iPhone. (Of course, if you are planning an app that runs on the iPhone as well as the iPod Touch, then you MUST test it on both. You cannot assume that if it is good on one it must be good on the other).
Also, by having an iPhone from day one, you can familiarize yourself with its user interface, its norms and the common metaphors the apps use. That will heavily feed into your own application design process, and make sure that your app looks, feels, and works like a first class iPhone citizen.
From experience developing on other mobile platforms, once you get to a certain point, it really is best to have a physical device to test on. If this is something that you would also be using yourself, if it much easier to get some real world type of testing by using the application out and about.
I also think it helps one to understand the platform better by having the device or devices you are targeting with your app,
if you are going to develop native apps for the iphone, I would say get an iphone or ipod touch to target. emulators are good, but eventually you will need to target the real thing. if you are developing web specific content there are lots of things you can do without it (there are some great dev videos free from apples dev site which will only cost you a sign up) but eventually I would think you would still want to test with the real deal
Get a cheap used iPod touch, develop, get money, buy an iPhone 5.
I'm a nokia dev now, I'm thinking of going to iPhone, Actually I have the Mac to work, just the device itself ;)
I've tried iPhoney and compared to my iPhone (Mark 1) it's not the same, it's close - but not close enough to rely on if the interface is of importance to you.
You absolutely need the real device. The performance difference between the simulator and the actual iPhone/iPod Touch hardware is huge. Code that will run nice and fast in the simulator can easily turn out to be too slow to be usable on the real thing. Also the API provided by the simulator is not 100% identical to the real thing, so code that works fine in the sim, may not work on the device. The only way to know for sure is to test often on the actual device.
As others have mentioned, the iPod touch works well as a development device. So if you don't need any of the features of the iPhone, it's a good, cheaper, alternative.