Swift – Could not cast value of type ‘UINavigationController’

swiftxcode

I am implementing a search interface for my application, so basically I will pass the search keyword from one ViewController to another ViewController.

I have done this type of parameter passing several times but something seems strange this time. The destination ViewController is embedded in a Navigation Controller.

Now the code looks something like this.

override func prepareForSegue(segue: UIStoryboardSegue?, sender: AnyObject!) {
    if (segue?.identifier == "home_to_search") {

       var searchKeyword = txtSearchBarHome.text
       var svc = segue?.destinationViewController as! SearchViewController;
       svc.toPassSearchKeyword = searchKeyword;

       //let nav = segue?.destinationViewController as! UINavigationController
       //let svc = nav.topViewController as! SearchViewController
       //svc.toPassSearchKeyword = searchKeyword;
    }
}

I have already explored these questions
DestinationViewController Segue and UINavigationController swift, How do I segue values when my ViewController is embedded in an UINavigationController? with no luck.

What makes me wonder is that I already have ViewControllers embedded in Navigation Controllers that I can pass parameters by segueing. However, in this case it throws a Could not cast value of type 'UINavigationController' error. If I try the commented code above it does not throw an error there, but at the AppDelegate class.

Best Answer

Answering my own question. In this case we need to access the child view by doing something like this:

let nav = segue?.destinationViewController as! UINavigationController
let svc = nav.topViewController as! SearchViewController
svc.toPassSearchKeyword = searchKeyword;

Related Solutions

Ios – DestinationViewController Segue and UINavigationController swift

You only need to access the navigation controller's topViewController, which will be the AddEventViewController. Here is the code:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "fromEventTableToAddEvent" {

        let nav = segue.destinationViewController as! UINavigationController
        let addEventViewController = nav.topViewController as! AddEventViewController

        addEventViewController.newTagArray = newTagArray

    }
}

R – CMake: how do you copy private frameworks into the application bundle under OS X

Here's what I'm doing:

1) In my framework CMakeLists.txt file, I have the following:

IF (APPLE)
       SET_TARGET_PROPERTIES( MyFramework PROPERTIES FRAMEWORK true)
       SET_TARGET_PROPERTIES( MyFramework PROPERTIES
           XCODE_ATTRIBUTE_INSTALL_PATH @executable_path/../Frameworks/  )
ENDIF (APPLE)

The second "set_target_properties" line configures the framework to always be looked for in the application bundle in the Frameworks sub-folder.

2) In my top-level CMakeLists.txt file, I add setup a unified binary output directory:

SET (CMAKE_LIBRARY_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/Bin)
SET (CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/Bin )
SET (CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/Bin )

3) Then, in my applications' CMakeLists.txt file, I have the following:

IF (APPLE)
       ADD_CUSTOM_COMMAND(
               TARGET MyApp
               POST_BUILD
               COMMAND ${PYTHON_EXECUTABLE}
               ARGS ${CMAKE_HOME_DIRECTORY}/CopyFramework.py
               --binary ${PROJECT_BINARY_DIR}/Bin
               --framework MyFramework.framework
               --app MyApp.app

    )
ENDIF (APPLE)

This calls out to my python script, which does the work of assembling the src and dest paths, and actually copying the Framework.

The final trick is that since this is a Mac only thing, I can rely on an Xcode environment variable within the Python script:

           config= os.environ["CONFIGURATION"]

This allows me to assemble the complete path to the actual binary locations of the framework and the app.

The one thing I wish was that there was a CMake variable that would expand to the current Config within the context of the ADD_CUSTOM_COMMAND... It'd be nice to not have to resort to using the Xcode environment variable.

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