# Sudden "overrides nothing" errors appear, no recent change to Kotlin build version **URL:** \ **Category:** Support\ **Created:** [December 5, 2017, 10:49pm UTC](https://discuss.kotlinlang.org/t/sudden-overrides-nothing-errors-appear-no-recent-change-to-kotlin-build-version/5690 "2017-12-05T22:49:25Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![harrypotter](https://avatars.discourse-cdn.com/v4/letter/h/ee7513/32.png) [@harrypotter](https://discuss.kotlinlang.org/u/harrypotter)\ **Post date:** [December 5, 2017, 10:49pm UTC](https://discuss.kotlinlang.org/t/sudden-overrides-nothing-errors-appear-no-recent-change-to-kotlin-build-version/5690/1 "2017-12-05T22:49:25Z")
Just today I am trying to build an app module in Android Studio, with Kotlin 1.1.51. This code to implement PagerAdapter has compiled for a long time, but suddenly it is getting confused with overriding function parameter and/or return types of Java interface. ``` internal inner class RegistrationPagerAdapter : PagerAdapter(), ViewPager.OnPageChangeListener { var expanded: Boolean = false set(value) { if (field == value) return field = value notifyDataSetChanged() this@LoginActivity.pageIndicator.notifyDataSetChanged() } val layouts = arrayOf(R.layout.fragment_login, R.layout.fragment_reg_1, R.layout.fragment_reg_2, R.layout.fragment_reg_3, R.layout.fragment_reg_4) override fun instantiateItem(container: ViewGroup, position: Int): ViewDataBinding? { val layout = layouts[position] return when (layout) { R.layout.fragment_login -> this@LoginActivity.setupLogin(container) R.layout.fragment_reg_1 -> this@LoginActivity.setupPage1(container) R.layout.fragment_reg_2 -> this@LoginActivity.setupPage2(container) R.layout.fragment_reg_3 -> this@LoginActivity.setupPage3(container) R.layout.fragment_reg_4 -> this@LoginActivity.setupPage4(container) else -> throw IllegalStateException("unknown item in RegistrationPagerAdapter") } } override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) { when (layouts[position]) { R.layout.fragment_login -> this@LoginActivity.loginBinding = null R.layout.fragment_reg_1 -> this@LoginActivity.reg1Binding = null R.layout.fragment_reg_2 -> this@LoginActivity.reg2Binding = null R.layout.fragment_reg_3 -> this@LoginActivity.reg3Binding = null R.layout.fragment_reg_4 -> this@LoginActivity.reg4Binding = null } container.removeView((`object` as ViewDataBinding).root) } override fun isViewFromObject(view: View?, `object`: Any): Boolean { if (`object` === this@LoginActivity.loginBinding) return view === this@LoginActivity.loginBinding?.root if (`object` === this@LoginActivity.reg1Binding) return view === this@LoginActivity.reg1Binding?.root if (`object` === this@LoginActivity.reg2Binding) return view === this@LoginActivity.reg2Binding?.root if (`object` === this@LoginActivity.reg3Binding) return view === this@LoginActivity.reg3Binding?.root if (`object` === this@LoginActivity.reg4Binding) return view === this@LoginActivity.reg4Binding?.root throw IllegalStateException("unknown item in RegistrationPagerAdapter") } override fun restoreState(state: Parcelable, loader: ClassLoader?) { this.expanded = Parcels.unwrap(state) super.restoreState(state, loader) } ... ``` And now, I suddenly have errors e: (1072, 20): Class ‘RegistrationPagerAdapter’ is not abstract and does not implement abstract base class member public abstract fun isViewFromObject(@NonNull p0: View, @NonNull p1: Any): Boolean defined in android.support.v4.view.PagerAdapter e: (1085, 76): Return type of ‘instantiateItem’ is not a subtype of the return type of the overridden member ‘@NonNull public open fun instantiateItem(@NonNull p0: ViewGroup, p1: Int): Any defined in android.support.v4.view.PagerAdapter’ e: (1108, 9): ‘isViewFromObject’ overrides nothing e: (1155, 9): ‘restoreState’ overrides nothing The IDE doesn’t show an error in the open source file. I really can’t imagine why these would suddenly start to appear. IDE has Kotlin plugin of same version as dependency in build.gradle ---
**Author:** ![alghraibeh](https://avatars.discourse-cdn.com/v4/letter/a/e9a140/32.png) [@alghraibeh](https://discuss.kotlinlang.org/u/alghraibeh)\ **Post date:** [December 6, 2017, 8:21am UTC](https://discuss.kotlinlang.org/t/sudden-overrides-nothing-errors-appear-no-recent-change-to-kotlin-build-version/5690/2 "2017-12-06T08:21:17Z")
Just remove nullable ‘?’ from you arguments on overrided function 1- override fun isViewFromObject(view: View?, `object`: Any): Boolean {} 2- override fun restoreState(state: Parcelable, loader: ClassLoader?) {} 3- override fun instantiateItem(container: ViewGroup, position: Int): ViewDataBinding? {} To 1- override fun isViewFromObject(view: View, `object`: Any): Boolean {} 2- override fun restoreState(state: Parcelable, loader: ClassLoader) {} 3- override fun instantiateItem(container: ViewGroup, position: Int): ViewDataBinding {} ---
**Author:** ![pdvrieze](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/pdvrieze/32/1882_2.png) [@pdvrieze](https://discuss.kotlinlang.org/u/pdvrieze)\ **Post date:** [December 6, 2017, 1:49pm UTC](https://discuss.kotlinlang.org/t/sudden-overrides-nothing-errors-appear-no-recent-change-to-kotlin-build-version/5690/3 "2017-12-06T13:49:58Z")
Did you perhaps update the android/support library version? Google has been adding annotations, also for Kotlin compatibility. This has probably interfered with your code. ---
**Author:** ![harrypotter](https://avatars.discourse-cdn.com/v4/letter/h/ee7513/32.png) [@harrypotter](https://discuss.kotlinlang.org/u/harrypotter)\ **Post date:** [December 6, 2017, 8:55pm UTC](https://discuss.kotlinlang.org/t/sudden-overrides-nothing-errors-appear-no-recent-change-to-kotlin-build-version/5690/4 "2017-12-06T20:55:52Z")
Thanks, I think that was it. Though strangely I have done full builds since changing library versions! I don’t understand why the editor thinks the code is fine. Bug in analyzers? ---
**Author:** ![Xerus](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/xerus/32/4499_2.png) [@Xerus](https://discuss.kotlinlang.org/u/Xerus)\ **Post date:** [December 6, 2017, 10:25pm UTC](https://discuss.kotlinlang.org/t/sudden-overrides-nothing-errors-appear-no-recent-change-to-kotlin-build-version/5690/5 "2017-12-06T22:25:25Z")
maybe you haven’t updated your analyzer version yet? For me the analyzer version was still set to Kotlin 1.1 and then i wondered why isInitialized for a lateinit variable wouldn’t work… Something similar may be happening to you