Using Cocoapods libraries in Flutter iOS platform specific code

I'm trying to use a Cocoapods library (for an external SDK) but I haven't found any documentation to do it. I've already integrated it in the Android part by just adding a line to the Gradle file.

Simply, I would like to create (or maybe find) a podfile where I could add my dependency and use it in AppDelegate.swift file.

What I tried so far is run pod init in ios/ folder and then add my pod (pod 'Charts' for example) and run pod install but it says:

[!] CocoaPods did not set the base configuration of your project because your project already has a custom config set. In order for CocoaPods integration to work at all, please either set the base configurations of the target Runner to Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig or include the Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig in your build configuration (Flutter/Release.xcconfig).

And then when I try to build on Xcode, it gives me this error:

error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.

I think I'm doing it the right way and I've found nothing to help me on Flutter.io documentation.

Thanks in advance for your help!

After you run pod init and pod install in the ios/ folder, add

#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"

to ios/Flutter/Debug.xcconfig

and add

#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.profile.xcconfig"

to ios/Flutter/Release.xcconfig