Calling to a variable of swift view controller file in Objective-C

I have a project that is a cross of Swift and Objective-C using a bridging-header.

In my main ViewController.swift file, outside of the class declaration, I have this code:

var mainView = ViewController()

In other views that I segue to, I can use this to call a function to run back on the main ViewController by using mainView.runFunction()

How can I call this function in an Objective-C .m implementation file?

Thanks!

asked Dec 31 '18 at 13:07

RanLearns

2,25433554

add a comment |

I have a project that is a cross of Swift and Objective-C using a bridging-header.

In my main ViewController.swift file, outside of the class declaration, I have this code:

var mainView = ViewController()

In other views that I segue to, I can use this to call a function to run back on the main ViewController by using mainView.runFunction()

How can I call this function in an Objective-C .m implementation file?

Thanks!

asked Dec 31 '18 at 13:07

RanLearns

2,25433554

add a comment |

I have a project that is a cross of Swift and Objective-C using a bridging-header.

In my main ViewController.swift file, outside of the class declaration, I have this code:

var mainView = ViewController()

In other views that I segue to, I can use this to call a function to run back on the main ViewController by using mainView.runFunction()

How can I call this function in an Objective-C .m implementation file?

Thanks!

asked Dec 31 '18 at 13:07

RanLearns

2,25433554

I have a project that is a cross of Swift and Objective-C using a bridging-header.

In my main ViewController.swift file, outside of the class declaration, I have this code:

var mainView = ViewController()

In other views that I segue to, I can use this to call a function to run back on the main ViewController by using mainView.runFunction()

How can I call this function in an Objective-C .m implementation file?

Thanks!

ios objective-c swift uiviewcontroller

asked Dec 31 '18 at 13:07

RanLearns

2,25433554

asked Dec 31 '18 at 13:07

RanLearns

2,25433554

asked Dec 31 '18 at 13:07

RanLearns

2,25433554

asked Dec 31 '18 at 13:07

RanLearns

2,25433554

asked Dec 31 '18 at 13:07

RanLearns

2,25433554

add a comment |

3 Answers
3

active

oldest

votes

First of all for using swift in objective-c you need to import TargetName-Swift.h. Note that it's the target name.

For more information look at this.

You can achieve what you want in this way:

ViewController *mainView = [[UIViewController alloc] init];

[mainView runFunction];

Also you should declare your runFunction with @objc to use it in objective-c like below:

@objc func runFunction {

    // what you want to do ...

}

edited Jan 5 at 7:35

answered Dec 31 '18 at 14:02

Arash Etemad

685418

Thanks for answering. Even though I have a ViewController.swift file and added @objc to its class definition, your code pops up the error "Unknown receiver ViewController" - if I add the #import "project-Swift.h" then the view controller is recognized in the first line of your code, but the second line shows error "No visible @interface for 'UIViewController' declares the selector 'runFunction'"

– RanLearns
Jan 1 at 4:30

@RanLearns answer updated. that was a slip of the tongue!

– Arash Etemad
Jan 1 at 8:22

add a comment |

Follow this apple article and done : Load Swift in Objective-C.
Or I already did is a "trick" using "@objc" key, look at this little explanation: What is @objc attribute, one easy way is just create a helper function that will be visible to your Objective-c class and done like:

@objc func retrieveMainView() -> UIViewController { return MyViewController() }

And you call this from your objective-c class, maybe you need to anotate your swift class with @objc, look at this two reference and you will get the idea and figure out for sure .

answered Dec 31 '18 at 13:40

Felipe Florencio

1848

add a comment |

In your Objective file i.e. .m file add below import statement:

import "<ProjectName>-Swift.h"

For example your project name is MyProject, so import statement would look like:

import "MyProject-Swift.h"

And call your function like: [mainView runFunction];

I hope this will help. You can also refer one of my answer:
How can I import Swift code to Objective-C?

answered Dec 31 '18 at 14:04

Dheeraj D

2,47221226

Thanks for answering. I believe my import statement is correct (no errors upon running) but the [mainView runFunction]; is erroring as Use of undeclared identifier 'mainView'

– RanLearns
Jan 1 at 4:38

Is your issue resolved? @RanLearns

– Dheeraj D
Jan 3 at 5:48

Yes, thank you. I marked another answer as correct. I had to instantiate a ViewController before I could call a function on it.

– RanLearns
Jan 4 at 13:20

add a comment |

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3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

First of all for using swift in objective-c you need to import TargetName-Swift.h. Note that it's the target name.

For more information look at this.

You can achieve what you want in this way:

ViewController *mainView = [[UIViewController alloc] init];

[mainView runFunction];

Also you should declare your runFunction with @objc to use it in objective-c like below:

@objc func runFunction {

    // what you want to do ...

}

edited Jan 5 at 7:35

answered Dec 31 '18 at 14:02

Arash Etemad

685418

Thanks for answering. Even though I have a ViewController.swift file and added @objc to its class definition, your code pops up the error "Unknown receiver ViewController" - if I add the #import "project-Swift.h" then the view controller is recognized in the first line of your code, but the second line shows error "No visible @interface for 'UIViewController' declares the selector 'runFunction'"

– RanLearns
Jan 1 at 4:30

@RanLearns answer updated. that was a slip of the tongue!

– Arash Etemad
Jan 1 at 8:22

add a comment |

First of all for using swift in objective-c you need to import TargetName-Swift.h. Note that it's the target name.

For more information look at this.

You can achieve what you want in this way:

ViewController *mainView = [[UIViewController alloc] init];

[mainView runFunction];

Also you should declare your runFunction with @objc to use it in objective-c like below:

@objc func runFunction {

    // what you want to do ...

}

edited Jan 5 at 7:35

answered Dec 31 '18 at 14:02

Arash Etemad

685418

Thanks for answering. Even though I have a ViewController.swift file and added @objc to its class definition, your code pops up the error "Unknown receiver ViewController" - if I add the #import "project-Swift.h" then the view controller is recognized in the first line of your code, but the second line shows error "No visible @interface for 'UIViewController' declares the selector 'runFunction'"

– RanLearns
Jan 1 at 4:30

@RanLearns answer updated. that was a slip of the tongue!

– Arash Etemad
Jan 1 at 8:22

add a comment |

First of all for using swift in objective-c you need to import TargetName-Swift.h. Note that it's the target name.

For more information look at this.

You can achieve what you want in this way:

ViewController *mainView = [[UIViewController alloc] init];

[mainView runFunction];

Also you should declare your runFunction with @objc to use it in objective-c like below:

@objc func runFunction {

    // what you want to do ...

}

edited Jan 5 at 7:35

answered Dec 31 '18 at 14:02

Arash Etemad

685418

First of all for using swift in objective-c you need to import TargetName-Swift.h. Note that it's the target name.

For more information look at this.

You can achieve what you want in this way:

ViewController *mainView = [[UIViewController alloc] init];

[mainView runFunction];

Also you should declare your runFunction with @objc to use it in objective-c like below:

@objc func runFunction {

    // what you want to do ...

}

edited Jan 5 at 7:35

answered Dec 31 '18 at 14:02

Arash Etemad

685418

edited Jan 5 at 7:35

answered Dec 31 '18 at 14:02

Arash Etemad

685418

answered Dec 31 '18 at 14:02

Arash Etemad

685418

answered Dec 31 '18 at 14:02

Arash Etemad

685418

Thanks for answering. Even though I have a ViewController.swift file and added @objc to its class definition, your code pops up the error "Unknown receiver ViewController" - if I add the #import "project-Swift.h" then the view controller is recognized in the first line of your code, but the second line shows error "No visible @interface for 'UIViewController' declares the selector 'runFunction'"

– RanLearns
Jan 1 at 4:30

@RanLearns answer updated. that was a slip of the tongue!

– Arash Etemad
Jan 1 at 8:22

add a comment |

Thanks for answering. Even though I have a ViewController.swift file and added @objc to its class definition, your code pops up the error "Unknown receiver ViewController" - if I add the #import "project-Swift.h" then the view controller is recognized in the first line of your code, but the second line shows error "No visible @interface for 'UIViewController' declares the selector 'runFunction'"

– RanLearns
Jan 1 at 4:30

@RanLearns answer updated. that was a slip of the tongue!

– Arash Etemad
Jan 1 at 8:22

Thanks for answering. Even though I have a ViewController.swift file and added @objc to its class definition, your code pops up the error "Unknown receiver ViewController" - if I add the #import "project-Swift.h" then the view controller is recognized in the first line of your code, but the second line shows error "No visible @interface for 'UIViewController' declares the selector 'runFunction'"

– RanLearns
Jan 1 at 4:30

@RanLearns answer updated. that was a slip of the tongue!

– Arash Etemad
Jan 1 at 8:22

add a comment |

@objc func retrieveMainView() -> UIViewController { return MyViewController() }

And you call this from your objective-c class, maybe you need to anotate your swift class with @objc, look at this two reference and you will get the idea and figure out for sure .

answered Dec 31 '18 at 13:40

Felipe Florencio

1848

add a comment |

@objc func retrieveMainView() -> UIViewController { return MyViewController() }

And you call this from your objective-c class, maybe you need to anotate your swift class with @objc, look at this two reference and you will get the idea and figure out for sure .

answered Dec 31 '18 at 13:40

Felipe Florencio

1848

add a comment |

@objc func retrieveMainView() -> UIViewController { return MyViewController() }

And you call this from your objective-c class, maybe you need to anotate your swift class with @objc, look at this two reference and you will get the idea and figure out for sure .

answered Dec 31 '18 at 13:40

Felipe Florencio

1848

@objc func retrieveMainView() -> UIViewController { return MyViewController() }

And you call this from your objective-c class, maybe you need to anotate your swift class with @objc, look at this two reference and you will get the idea and figure out for sure .

answered Dec 31 '18 at 13:40

Felipe Florencio

1848

answered Dec 31 '18 at 13:40

Felipe Florencio

1848

answered Dec 31 '18 at 13:40

Felipe Florencio

1848

answered Dec 31 '18 at 13:40

Felipe Florencio

1848

add a comment |

In your Objective file i.e. .m file add below import statement:

import "<ProjectName>-Swift.h"

For example your project name is MyProject, so import statement would look like:

import "MyProject-Swift.h"

And call your function like: [mainView runFunction];

I hope this will help. You can also refer one of my answer:
How can I import Swift code to Objective-C?

answered Dec 31 '18 at 14:04

Dheeraj D

2,47221226

Thanks for answering. I believe my import statement is correct (no errors upon running) but the [mainView runFunction]; is erroring as Use of undeclared identifier 'mainView'

– RanLearns
Jan 1 at 4:38

Is your issue resolved? @RanLearns

– Dheeraj D
Jan 3 at 5:48

Yes, thank you. I marked another answer as correct. I had to instantiate a ViewController before I could call a function on it.

– RanLearns
Jan 4 at 13:20

add a comment |

In your Objective file i.e. .m file add below import statement:

import "<ProjectName>-Swift.h"

For example your project name is MyProject, so import statement would look like:

import "MyProject-Swift.h"

And call your function like: [mainView runFunction];

I hope this will help. You can also refer one of my answer:
How can I import Swift code to Objective-C?

answered Dec 31 '18 at 14:04

Dheeraj D

2,47221226

Thanks for answering. I believe my import statement is correct (no errors upon running) but the [mainView runFunction]; is erroring as Use of undeclared identifier 'mainView'

– RanLearns
Jan 1 at 4:38

Is your issue resolved? @RanLearns

– Dheeraj D
Jan 3 at 5:48

Yes, thank you. I marked another answer as correct. I had to instantiate a ViewController before I could call a function on it.

– RanLearns
Jan 4 at 13:20

add a comment |

In your Objective file i.e. .m file add below import statement:

import "<ProjectName>-Swift.h"

For example your project name is MyProject, so import statement would look like:

import "MyProject-Swift.h"

And call your function like: [mainView runFunction];

I hope this will help. You can also refer one of my answer:
How can I import Swift code to Objective-C?

answered Dec 31 '18 at 14:04

Dheeraj D

2,47221226

In your Objective file i.e. .m file add below import statement:

import "<ProjectName>-Swift.h"

For example your project name is MyProject, so import statement would look like:

import "MyProject-Swift.h"

And call your function like: [mainView runFunction];

I hope this will help. You can also refer one of my answer:
How can I import Swift code to Objective-C?

answered Dec 31 '18 at 14:04

Dheeraj D

2,47221226

answered Dec 31 '18 at 14:04

Dheeraj D

2,47221226

answered Dec 31 '18 at 14:04

Dheeraj D

2,47221226

answered Dec 31 '18 at 14:04

Dheeraj D

2,47221226

Thanks for answering. I believe my import statement is correct (no errors upon running) but the [mainView runFunction]; is erroring as Use of undeclared identifier 'mainView'

– RanLearns
Jan 1 at 4:38

Is your issue resolved? @RanLearns

– Dheeraj D
Jan 3 at 5:48

Yes, thank you. I marked another answer as correct. I had to instantiate a ViewController before I could call a function on it.

– RanLearns
Jan 4 at 13:20

add a comment |

Thanks for answering. I believe my import statement is correct (no errors upon running) but the [mainView runFunction]; is erroring as Use of undeclared identifier 'mainView'

– RanLearns
Jan 1 at 4:38

Is your issue resolved? @RanLearns

– Dheeraj D
Jan 3 at 5:48

Yes, thank you. I marked another answer as correct. I had to instantiate a ViewController before I could call a function on it.

– RanLearns
Jan 4 at 13:20

Thanks for answering. I believe my import statement is correct (no errors upon running) but the [mainView runFunction]; is erroring as Use of undeclared identifier 'mainView'

– RanLearns
Jan 1 at 4:38

Is your issue resolved? @RanLearns

– Dheeraj D
Jan 3 at 5:48

Yes, thank you. I marked another answer as correct. I had to instantiate a ViewController before I could call a function on it.

– RanLearns
Jan 4 at 13:20

add a comment |

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