Design by .xib or by .m

Friends, I have an application, ten pages, but full of buttons(with background images), big size background images, box image for set of controls, etc. I have designed all those in XIB files. It is working fine, but in fe开发者_高级运维w minutes, my application shows "Received memory warning level=1". Some developers suggesting me to do designs using .m files, instead of doing it in XIB file. They are telling that it will reduce memory usage of graphics.

Is it true? Will designing by .m file reduce memory usage? Please advice, Thank you.

Did you check if you have memory leaks in your app? XIB files use just constant amount of memory. Also, creating the same interface in the code consumes almost the same amount of memory.

In any case, XIB consumes only a definite amount of memory once you load it. So, if you receive memory warning not immediately after loading the XIB, but a few second afterwards, the real reason causing the memory warning is definitely elsewhere.

Are you doing retain and release correctly? Run static analyzer from the Xcode, remove all warnings reported, and then use Instruments to see if you have memory leaks.

Designing a UI in Nib-file, or doing the same manually in code makes no difference on memory consumptions. The end result is the same amount of life objects in memory, a Nib-file is only serialized objects, no other magic.

Nib-files and Interface Builder only allows you to design UI faster with drag and drop, instead of trial-and-error in code. All the bonuses that Nib-files comes with has a small price; you must bother yourself to at least read the documentation on how to use them! Otherwise you will get into trouble. You can bet that any person advising against Nib-files flat out, have no idea what they are or how they work, and would not be bothered to learn either.

Go to http://developer.apple.com and search for "nib", you want to at least read "Core Competencies - Nib file", and "Memory Management of Nib Objects". Then decide if Nib-file is good or not for your task at hand.

Yea, it is true that you should do it in code. However, if you are receiving a memory warning, it really does not matter. You will have to remove the contents of on page before creating the contents of the other, otherwise it is the same as just using the .xib file. Infact, I once made an application with lots of windows, and I got the same memory warning message.

It is actually very easy to figure out why (I was surprised when I heard). Basically, every single thing in the .xib file is an object. When you have a lot of objects, you run out of memory. What you need to do is run code similar to te following when you change pages.

- (void) changeToPageOne {
    [theSecondElement release];
    //Then you make the new interface element
    UIImageView *theElement = [[UIImageView alloc] initWithFrame:(CGRect)];
    //You will need the coordinates from the .xib file for the CGRect there
    [theElement setImage:(UIImage*)];
    [theView addSubview:theElement];
}

You do the same thing for the next page. The problem here is that you will need to be able to keep track of the UIImageView, but it is basically just a local variable here. You may want to add it to an array, and just remove the objects in the array when you change pages. I hope this helps!