"No calls to throwing functions occur within 'try' expression" [closed] - ios

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I try to handle exception but a warning occurs. "No calls to throwing functions occur within 'try' expression"
do{
var folderID = getFolder()?
}catch{
}

The warning clearly states that getFolder() does not throw. To get rid of the warning remove the do - catch block
let folderID = getFolder()
Note:
In Swift you cannot catch arbitrary exceptions like in Objective-C.
A do - catch block catches only Errors thrown by methods marked with the throws keyword.

Related

"'_' can only appear in a pattern or on the left side of an assignment"-Error when creating closure [closed]

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Closed 1 year ago.
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I'm creating a closure to call from a storyboard outside the framework I'm creating.
However, when trying to implement said closure through the guidance of this SO post, I'm getting the following errors:
1. '_' can only appear in a pattern or on the left side of an assignment
2. Consecutive statements on a line must be separated by ';'
3. Expected expression
Here is the current code inside my swift file:
//Here is where I'm getting the mentioned 3 errors
var sliderChangeforward: (UISlider) -> Void { _ in }
#IBAction func sliderDidChange(_ sender: UISlider){
...
sliderChangeforward(sender)
}
Any help is greatly appreciated.
You omitted the equals sign.
var sliderChangeforward: (UISlider) -> Void = { _ in }

Access violation at address 005D3653 in module 'Project1.exe [duplicate]

This question already has answers here:
Debugging Access Violation errors?
(4 answers)
Closed 5 years ago.
I face the following error when I try to debug. I am just newbie with Delphi, please guide how to correct this error.
First chance exception at $73B1A9F2. Exception class EAccessViolation with message 'Access violation at address 005D3653 in module 'Project1.exe'. Read of address 000003AC'. Process Project1.exe (34780)
When break this source code is shown:
if fsCreating in FFormState then
if Value then
Include(FFormState, fsVisible) else
Exclude(FFormState, fsVisible)
You are calling a method on an invalid reference. For instance something like
Obj.DoSomething;
where Obj is not valid. Because the attempted read address is 000003AC, close to zero, almost certainly the reference is nil.
Track back up your call stack until you find the call with the nil reference.

Does Apple encourage you to throw only single error type in Swift 2.0?

Please correct me if I'm wrong, but from what I understand with Swift 2.0 Apple really encourage you against having many catch statements to handle different error types. Instead in most cases your do-catch block would have only one catch statement that catches everything.
I'm not saying that this is a good or bad idea. But I just don't see any other option. You can't be 100% sure about error type that you may or may not receive after a function call. This is because there is no way to specify a list of possible errors in a function definition after "throws" statement. So you would need to dig into the call stack of the function to find this out. And this could be a very deep stack... Will anyone actually do this every time just to get the idea what to catch?
To demonstrate what I mean:
func funcA() throws {
throw SomeError
}
func funcB() throws {
if something {
throw OtherError
}
try funcA()
}
func funcX() throws {
try funcB()
}
Now I if I want to call funcX - I don't really know that it can throw SomeError or OtherError by looking at funcX definition. In order to find this out I will need to go and review the entire call stack tree from funcX. While it doesn't look too complex in the extremely short example above. But in a real world source code this may become an issue.

Ios Add objects in a NSMutableArray [closed]

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how can I add an object in an array by clicking a button
I use this methode :
- (void)insertNewObject:(id)sender
{
[orderListe addObject:[[DataOrder alloc]initWithName:#"Michael" price:18 taille:#"junior" supplement:#"boeuf"]];
}
When I do that my application crash and say :
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[DataOrder initWithName:]: unrecognized selector sent to instance 0x8aa4fa0'
What can i do to simply add an object to an array ?
Thank you
The error your getting has to do with the DataOrder object. During it's initialization it ran into an error. You're sending it some value it isn't expecting.
Perhaps try and separate the line where you alloc the Data Order object and try to add it to the array?
DataOrder *do = [[DataOrder alloc] initWithName....];
[orderListe addObject: do];
this will let you see where you messed up?
Of course that you can add an object to an array. The exception is thrown because the method initWithName:price: ... is not implemented in the DataOrder class.

Parse Quickstart error [closed]

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I'm new to Objective-C and to programming to be honest. Working on a bit of a project and have had the following returned when I try and use the Parse quickstart. Any suggestions?
2013-08-21 21:47:41.388 ParseStarterProject[3284:c07] * Terminating
app due to uncaught exception 'NSInvalidArgumentException', reason:
'cannot setReadAccess for unsaved user'
* First throw call stack: (0x21f4012 0x1d27e7e 0x21f3deb 0x35057 0x3555d 0xaa33 0x32a5 0x2f76 0x3332 0xac5c 0x2e00 0xf761c7 0xf76232
0xec53d5 0xec5cc1 0x2636 0xe92157 0xe92747 0xe9394b 0xea4cb5 0xea5beb
0xe97698 0x214fdf9 0x214fad0 0x2169bf5 0x2169962 0x219abb6 0x2199f44
0x2199e1b 0xe9317a 0xe94ffc 0x2495 0x2395) libc++abi.dylib: terminate
called throwing an exception (lldb)
The Parse SDK is throwing an exception. From the error message, it looks like the problem is that you're sending -setReadAccess for an unsaved user. That makes sense -- it'd probably be difficult to read from an user object that hasn't yet been saved.

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