kotlin 'onCreate' overrides nothing

Question

I am using component development, in my common module BaseActivity.kt and BaseFragment.kt. The following problems occur when other modules inherit them

> D:\Android\OneDaily\module_main\src\main\java\com\boco\main\MainActivity.kt
> Error:(7, 24) Unresolved reference: base 
> Error:(9, 22) Unresolved reference: BaseActivity 
> Error:(21, 5) 'onCreate' overrides nothing
> Error:(17, 5) 'getLayoutRes' overrides nothing 
> Error:(22, 15) Unresolved reference: onCreate 
> Error:(27, 22) Unresolved reference: findViewById 
> Error:(42, 34) Unresolved reference: supportFragmentManager
> D:\Android\OneDaily\module_main\src\main\java\com\boco\main\TimelineFragment.kt
> Error:(7, 24) Unresolved reference: base 
> Error:(10, 5) 'getLayoutRes' overrides nothing 
> Error:(9, 26) Unresolved reference: BaseFragment
> Error:(14, 5) 'onCreateView' overrides nothing 
> Error:(15, 22) Unresolved reference: onCreateView

BaseActivity.kt:

abstract class BaseActivity : AppCompatActivity() {  
    init {  
        AppCompatDelegate.setCompatVectorFromResourcesEnabled(true)  
    }  
    abstract fun getLayoutRes(): Int  
    override fun onCreate(savedInstanceState: Bundle?) {  
        super.onCreate(savedInstanceState)  
        setContentView(getLayoutRes())  
    }  
}  

MainActivity.kt

class MainActivity : BaseActivity() {

    private lateinit var mBottomNav: BottomNavigationView

    private var mFragment1 = TimelineFragment() as Fragment
    private var mFragment2 = TimelineFragment() as Fragment
    private var mFragment3 = TimelineFragment() as Fragment

    override fun getLayoutRes(): Int {
        return R.layout.activity_main
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

    }
}

Solution 1

It seems some functions have changed in the last update, just remove the '?' from the Bundle

Like this:

override fun onCreate(savedInstanceState: Bundle) {
    super.onCreate(savedInstanceState)
}

Solution 2

It can happen also in a Fragment class: I found the same issue for the method onCreateView; to avoid that, just remove the ? from the LayoutInflater parameter,

Like this:

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View?

Solution 3

I have to add "?" when using appcompat-v7:27.1.1

implementation "com.android.support:appcompat-v7:27.1.1

and

override fun onCreate(savedInstanceState : Bundle?){
    super.onCreate(savedInstanceState)
}

Comments

[alex]

Would help to see your code.

[Kiran Benny Joseph]

please share your code snippet

[Haresh Chhelana]

I have try your given code with Android Studio 3.0 stable version and it's working fine. have you using same or other version of android studio ?

[RootKit]

I am also using Android studio 3.0 But my MainActivity.kt is a baseActivity.kt that inherits from module. BaseActivity.kt inside the common module, MainActivity.kt inside module_main.I do not know if you are trying to do so

[saiedmomen]

I'm seeing the same error after moving to support library version 27.0.0

[tynn]

Unresolved reference: BaseActivity – this might be related to a configuration issue with Gradle...

[RootKit]

oh, thank you, really is the problem of Gradle. My common module did not apply plugin: 'kotlin-android' apply plugin: 'kotlin-android-extensions'

[Aba]

Maybe this might help: stackoverflow.com/questions/47016853/…

[RootKit]

Which version can remove '?'

[Emmanuel Guther]

Also, if you are getting same error but in a fragment, remove '?' in fragmentManager: FragmentManager

[romaneso]

This answer should be selected as the top-answer. Helped me out!

[jbass]

Worked for me for 27.0.2 as well.

[onmyway133]

Yeah, otherwise you will get "Caused by: java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull, parameter savedInstanceState"

[zeeshan]

Worked for me on Android Studio 3.3, appcompat-v7:28.0.0, compileSdkVersion 28

[Hannah S.]

I'm using Android 3.5 and had the same problem the OP had but for onCreateDialog() not onCreate(). I was using the example from developer.android.com/guide/topics/ui/dialogs.html#kotlin which had no ? after Bundle, but adding it fixed it. Thanks so much for the suggestion!

[mr5]

Had this problem but the solution was to add ? in Bundle. I'm using AS: 4.0, Kotlin: 1.3.72, Gradle: 4.9

[dicarlomagnus]

this works as well for override fun onDismiss(dialog: DialogInterface?) removing the nullable parameter to override fun onDismiss(dialog: DialogInterface)

[Taslim Oseni]

Worked like a charm!