Can any one tell me what is the best to handle exception in iOS (Objective C)?
I have the following two approaches:
- Use try/catch block.
- Do proper data handing for all model class.
What do you suggest?
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rmaddy
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Rahul Juyal
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3This question is too vague really. Do you have any specific use cases or any specific issues? – rmaddy Feb 11 '16 at 16:31
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This is a general question, If we have some thing wrong from json, like in json we get NULL value inside array/ dictionary etc – Rahul Juyal Feb 11 '16 at 16:32
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Apple has dropped exception handling in Swift. Guess why ? ;-) – vadian Feb 11 '16 at 16:33
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3Code defensively. Make no assumptions. – rmaddy Feb 11 '16 at 16:33
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Three years never used a try catch block – Myron Slaw Feb 11 '16 at 16:34
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@rmaddy defensively means.. not getting your point – Rahul Juyal Feb 11 '16 at 16:37
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After parsing your JSON, don't assume the dictionaries/arrays contain specific types of values. Check for `NSNull` objects, for example. If you get any exceptions it is because your code is making bad assumptions. – rmaddy Feb 11 '16 at 16:39
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For typical "best practice" no most people do not use try/catch in Objective-C. – Ben Kane Feb 11 '16 at 16:50
2 Answers
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Exceptions in Objective are only meant to be used for programming errors where there is no recovery (the app will terminate immediately).
Exception are not designed to be used for program control flow in Objective-C. Check for all possible errors and handle them at that point.
Further, there is no cleanup on catches across stack frames so full recovery is generally not possible.
zaph
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"fun recovery"? Did you mean "full recovery"? I like the idea of "fun recovery" though. :) – rmaddy Feb 11 '16 at 17:05
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Oops, yes full, fixed, thanks! @rmaddy you should know by now that I am a bad speller, worst typer and combining that with auto-correct is a recipe for disaster. ;-) – zaph Feb 11 '16 at 17:06
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On iOS, you should fix whatever is causing the exception. NSError is for errors that are expected (e.g. Backend returns invalid or not data). Exceptions are usy programming errors and should be fixed. Avoid try/catch, except when it is explicitly stated you should use it (e.g. Subclassing NSOperation).
Joride
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