when I want use swift file in objective c project and I declare an object from swift class, I get "Use of undeclared identifier" error.
the way that I pass:
coping swift file in project and type #objc before declare swift class
create header file in project manually
set "Defines module" in target to Yes
set objective-C bridging header in target to $(SRCROOT)/$(PRODUCT_MODULE_NAME)-Bridging-Header.h
declare #import "productModuleName-Bridging-Header.h" in objective-c file
use name_of_swift_class *s = [[name_of_swift_class alloc] init];
when I want use swift file in step 6 I get "Use of undeclared identifier" error. why?!!! do I have the mistake?
when I test this steps in new project I don't get error but in project that I want it return error.
thank you for your help
The problem is at Step 5 You should not be importing "productModuleName-Bridging-Header.h" instead you should be importing "productModuleName-Swift.h"
P.S- After making this change clean your project, clear your derived data and build it. It will work. Hope it helps :)
I'm working on creating my own framework, I added objective c files and its working fine after that I needed to add some swift file after adding swift file xcode is not giving me option of auto Creating Bridging then I followed Mix and Match approach. I followed everything which I thing I understand.
I want to access swift file into Objective c but I'm getting error of forward declaration so Here is sample code I attached, kindly guide me where I'm doing wrong.
TestObjectCFile.h
#import <Foundation/Foundation.h>
#class TestSwiftFile;
#interface TestObjCFile : NSObject
#end
TestObjectCFile.m
#import "TestObjCFile.h"
#import <TestFrameworkTry/TestFrameworkTry-Swift.h>
#import "TestFrameworkTry.h"
#implementation TestObjCFile
- (void)TestMethodForImportingSwiftFile
{
TestSwiftFile * testSwiftFile = [[TestSwiftFile alloc] init];
// TestSwiftFile * testSwiftFile = [self returnSwiftClassInstance];
NSLog(#"%#",testSwiftFile);
}
#end
TestSwiftFile.swift
import Foundation
And the error occur on TestObjectCFile.m following line.
TestSwiftFile * testSwiftFile = [[TestSwiftFile alloc] init];
as show attached picture.
Finally I got solution. I did following changes. Here below is to do list in your Framework.
Swift classes usage in Objective C classes
Use Open Keyword before class name in Swift
Use #objc Keyword before Open Keyword of Swift class
Import all header of objective c classes in Umbrella file
YourProject.h those are consuming Swift Classes.
Use #import <YourProjectName/YourProjectName-Swift.h> in Objective
c
I followed Apple's Mix and Match approach.
Note: sometimes the <YourProjectName/YourProjectName-Swift.h> file can not be imported into headers, but only into .m files. FYI, this file is created automatically by the compiler. If you search your project for it, you won't be able to find it, but if you ⌘ click on it (as a file imported in your code) in a file that is in your target, Xcode will (should) open it and show you all the Objective-C class interfaces for your Swift classes. To see the name for the Swift -> Objective-C module header, go to your target's Build Settings and search for $(SWIFT_MODULE_NAME)-Swift.h or simply -Swift.
I have written a library in Swift and I wasn't able to import it to my current project, written in Objective-C.
Are there any ways to import it?
#import "SCLAlertView.swift" - 'SCLAlertView.swift' file not found
You need to import ProductName-Swift.h. Note that it's the product name - the other answers make the mistake of using the class name.
This single file is an autogenerated header that defines Objective-C interfaces for all Swift classes in your project that are either annotated with #objc or inherit from NSObject.
Considerations:
If your product name contains spaces, replace them with underscores (e.g. My Project becomes My_Project-Swift.h)
If your target is a framework, you need to import <ProductName/ProductName-Swift.h>
Make sure your Swift file is member of the target
Here's what to do:
Create a new Project in Objective-C
Create a new .swift file
A popup window will appear and ask "Would You like to configure an Objective-C bridging Header".
Choose Yes.
Click on your Xcode Project file
Click on Build Settings
Find the Search bar and search for Defines Module.
Change value to Yes.
Search Product Module Name.
Change the value to the name of your project.
In App delegate, add the following : #import "YourProjectName-Swift.h"
Note: Whenever you want to use your Swift file you must be import following line :
#import "YourProjectName-Swift.h"
Instructions from the Apple website:
To import Swift code into Objective-C from the same framework
Under Build Settings, in Packaging, make sure the Defines Module
setting for that framework target is set to Yes. Import the Swift code
from that framework target into any Objective-C .m file within that
framework target using this syntax and substituting the appropriate
names:
#import "ProductName-Swift.h"
Revision:
You can only import "ProductName-Swift.h" in .m files.
The Swift files in your target will be visible in Objective-C .m files
containing this import statement.
To avoid cyclical references, don’t import Swift into an Objective-C
header file. Instead, you can forward declare a Swift class to use it
in an Objective-C header. Note that you cannot subclass a Swift class
in Objective-C.
If you're using Cocoapods and trying to use a Swift pod in an ObjC project you can simply do the following:
#import <FrameworkName>;
Go to build settings in your project file and search for "Objective-C Generated Interface Header Name. The value of that property is the name that you should include.
If your "Product Module Name" property (the one that the above property depends on by default) varies depending on whether you compile for test/debug/release/etc (like it does in my case), then make this property independent of that variation by setting a custom name.
Importing Swift file inside Objective-c can cause this error, if it doesn't import properly.
NOTE: You don't have to import Swift files externally, you just have to import one file which takes care of swift files.
When you Created/Copied Swift file inside Objective-C project. It would've created a bridging header automatically.
Check Objective-C Generated Interface Header Name at Targets -> Build Settings.
Based on above, I will import KJExpandable-Swift.h as it is.
Your's will be TargetName-Swift.h, Where TargetName differs based on your project name or another target your might have added and running on it.
As below my target is KJExpandable, so it's KJExpandable-Swift.h
First Step:-
Select Project Target -> Build Setting -> Search('Define') -> Define Module
update value No to Yes
"Defines Module": YES.
"Always Embed Swift Standard Libraries" : YES.
"Install Objective-C Compatibility Header" : YES.
Second Step:-
Add Swift file Class in Objective C ".h" File as below
#import <UIKit/UIKit.h>
#class TestViewController(Swift File);
#interface TestViewController(Objective C File) : UIViewController
#end
Import 'ProjectName(Your Project Name)-Swift.h' in Objective C ".m" file
//TestViewController.m
#import "TestViewController.h"
/*import ProjectName-Swift.h file to access Swift file here*/
#import "ProjectName-Swift.h"
If you have a project created in Swift 4 and then added Objective-C files, do it like this:
#objcMembers
public class MyModel: NSObject {
var someFlag = false
func doSomething() {
print("doing something")
}
}
Reference: https://useyourloaf.com/blog/objc-warnings-upgrading-to-swift-4/
There's one caveat if you're importing Swift code into your Objective-C files within the same framework. You have to do it with specifying the framework name and angle brackets:
#import <MyFramework/MyFramework-Swift.h>
MyFramework here is the "Product Module Name" build setting (PRODUCT_NAME = MyFramework).
Simply adding #import "MyFramework-Swift.h" won't work. If you check the built products directory (before such an #import is added, so you've had at least one successful build with some Swift code in the target), then you should still see the file MyFramework-Swift.h in the Headers directory.
Be careful with dashes and underscores, they can be mixed up and your Project Name and Target name won't be the same as SWIFT_MODULE_NAME.
Checkout the pre-release notes about Swift and Objective C in the same project
https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/BuildingCocoaApps/MixandMatch.html#//apple_ref/doc/uid/TP40014216-CH10-XID_75
You should be importing
#import "SCLAlertView-Swift.h"
Search for "Objective-C Generated Interface Header Name" in the Build Settings of the target you're trying to build (let's say it's MyApp-Swift.h), and import the value of this setting (#import "MyApp-Swift.h") in the source file where you're trying to access your Swift APIs.
The default value for this field is $(SWIFT_MODULE_NAME)-Swift.h. You can see it if you double-click in the value field of the "Objective-C Generated Interface Header Name" setting.
Also, if you have dashes in your module name (let's say it's My-App), then in the $(SWIFT_MODULE_NAME) all dashes will be replaced with underscores. So then you'll have to add #import "My_App-Swift.h".
If you want to use Swift file into Objective-C class, so from Xcode 8 onwards you can follow below steps:
If you have created the project in Objective-C:
Create new Swift file
Xcode will automatically prompt for Bridge-Header file
Generate it
Import "ProjectName-Swift.h" in your Objective-C controller (import in implementation not in interface) (if your project has space in between name so use underscore "Project_Name-Swift.h")
You will be able to access your Objective-C class in Swift.
Compile it and if it will generate linker error like: compiled with newer version of Swift language (3.0) than previous files (2.0) for architecture x86_64 or armv 7
Make one more change in your
Xcode -> Project -> Target -> Build Settings -> Use Legacy Swift Language Version -> Yes
Build and Run.
#import <TargetName-Swift.h>
you will see when you enter from keyboard #import < and after automaticly Xcode will advice to you.
only some tips about syntax, about Xcode everything has been said
you cannot import 'pure" functions, only classes, even if marked "public", so:
public func f1(){
print("f1");
}
will NOT be called in ANY way.
If You write classes., add inheritance from NSObject, other will NOT be usable.
if it inherits from NSObject, as below:
class Utils : NSObject{
static func aaa()->String{
return "AAA"
}
#objc static func bbb()->String{
return "BBB"
}
#objc private static func ccc()->String{
return "CCC"
}
}
in OBJC:
aaa() NOT called: "No known class method for selector 'aaa'"
bbb() ok
ccc() NOT called: "No known class method for selector 'aaa'"
Find the .PCH file inside the project. and then add #import "YourProjectName-Swift.h" This will import the class headers. So that you don't have to import into specific file.
#ifndef __IPHONE_3_0
#warning "This project uses features only available in iPhone SDK 3.0 and later."
#endif
#ifdef __OBJC__
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#import "YourProjectName-Swift.h"
#endif
I have done this before, normally without trouble, setting the bridging header, etc.
This time, I tried to import a Obj-C framwork (github.com/jensmeder/FSKModem/) into my swift project. When typing code I can "see" all the Obj-C methods.
But when I compile the code, I get errors like "Use of undeclared identifier 'delete'" or "Use of undeclared identifier 'new'". Example of code in a .m file that is giving the error:
_audioFormat = new AudioStreamBasicDescription();
I'm familiar with Swift and don't know about Obj-C but I guess "delete" or "new" should exist, right? Do they belong to some framework that I should add?
I can compile the original code in Obj-C without trouble, but I need to incorporate it in my project that is written in Swift.
Many thanks for any help
Some more information...
The following functions are inside the .m file. Do you know why the "new" and "delete" keywords are unrecognized? This works fine when compiled as a normal "Obj-C" project. The error appears in Swift project only (after bridging headers of course):
-(void)dealloc
{
[self disconnect:NULL];
if (_audioFormat)
{
delete _audioFormat;
}
}
-(void) setupAudioFormat
{
_audioFormat = new AudioStreamBasicDescription();
//...
}
Should I add some #include that I might be missing, besides Foundation?
new and delete are C++ keywords; you can use them in C++ files (usually .cpp or .cc) and in Objective-C++ files (always .mm). You cannot use them in Swift (.swift) or in Objective-C (.m) files.
It is perfectly valid to use an Objective-C class from an Objective-C++ file from Swift; you can use Objective-C to wrap C++ classes for Swift usage. However it is not valid to use C++ from plain Objective-C.
Quite probably you just need to rename your Objective-C file to .mm.
new and delete are keywords from C++ not from Swift or Objective-C.
Swift
let audioFormat = AudioStreamBasicDescription()
Objective-C
AudioStreamBasicDescription* audioFormat = [[AudioStreamBasicDescription alloc] init];
In Swift, you simply need to call the object initializer when creating an object.
_audioFormat = AudioStreamBasicDescription()
The new keyword is an Objective-C combo of alloc and init.
I'm trying to write a swift class that uses the Dropbox Sync API, but can't get swift to see the framework. The objective C in my project can use the Dropbox framework successfully. I have a bridging header that seems to be properly set up in the project settings and references <Dropbox/Dropbox.h>. But in my swift file it is as if I have done nothing.
This objective C code in my project works and is what I am trying to replicate in Swift:
#import <Dropbox/Dropbox.h>
...
if ([DBAccountManager sharedManager].linkedAccount == nil) {
[[DBAccountManager sharedManager] linkFromController:self];
[[DBAccountManager sharedManager] addObserver:self block:^(DBAccount *account) {
DBFilesystem *fileSystem = [[DBFilesystem alloc] initWithAccount:account];
[DBFilesystem setSharedFilesystem:fileSystem];
}];
As I said, I have <Dropbox/Dropbox.h> in the bridging header that Xcode automatically created for me. However this swift code fails to compile with the error 'Use of unresolved identifier 'DBAccountManager''
import UIKit
class PiecesListTableViewController : UITableViewController {
override func loadView() {
super.loadView()
// This fails with unresolved identifier 'DBAccountManager'
let accountManager = DBAccountManager.sharedManager
// As does this
let accountManagerNew = DBAccountManager(appKey:"", secret:"")
}
}
Any thoughts on how to get my swift code to be able to see the Dropbox framework?
I didn't manage to solve this. Instead I worked around it by abstracting all use of the Dropbox framework into objective C classes and using those in my swift code.
Actually I found the way to do it:
Create a dummy .m file so that XCode will ask you to create a bridging header, then delete the .m
Under project Build settings, add DropboxSDK.framework under Link Binary with Libraries
Open the bridging-header file and write in it #import <DropboxSDK/DropboxSDK.h>
XCode won't compile your code, and SourceKit Service will likely crash every time you'll open up a Swift file.
That's because of two errors in the Dropbox SDK (at least for a Swift environment):
Open the DropboxSDK.framework you linked before in Finder, then navigate to Headers folder
Open the file DBQuota.h and add #import <Foundation/Foundation.h> before #interface
Open the file DBSession+iOS.h and add #import <UIKit/UIKit.h> before #interface
Now you can use Dropbox SDK classes in your Swift files.
This will save you from creating an Objective-C wrapper on each class.