CODEWITHSUNDEEP
androidandroid-fragmentsnullpointerexceptionandroid-viewpagerandroid-tablayout
Foobar
Foobar

Reputation: 8467

Null Pointer Exception When Setting ViewPager for TabLayout

I have a fragment that will contain two other fragments that can be accessed through a TabLayout

I have the following Kotlin code: 

class TutorialFragment : Fragment() {

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

        val tutorialview = inflater.inflate(R.layout.fragment_tutorial, container, false )

        tutorialview.tutorialViewPager.adapter = TutorialFragmentPagerAdapter(context!!, fragmentManager!!)

        //Null Pointer Exception on this line 
        tabBar.setupWithViewPager(tutorialview.tutorialViewPager)


        return tutorialview
    }

    companion object {
        fun newInstance() = TutorialFragment()
    }
}

My code crashes with the exception:

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.design.widget.TabLayout.setupWithViewPager(android.support.v4.view.ViewPager)' on a null object reference
        at com.vedantroy.animefacekeyboard.home.tutorial.TutorialFragment.onCreateView(TutorialFragment.kt:23)

Update 1 -

As per the suggestion of Tuby,

I changed my code to: 

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

    Log.d("KEYBOARD-APP","Inside tutorial fragment onCreate()...")
    val tutorialView = inflater.inflate(R.layout.fragment_tutorial, container, false )
    tutorialView.tutorialViewPager.adapter = TutorialFragmentPagerAdapter(fragmentManager!!)
    tutorialView.tabBar.setupWithViewPager(tutorialView.tutorialViewPager)

    return tutorialView
}

However, although the fragment itself is now showing, the tabs are not.

Upvotes: 1

Views: 1430

Answers (2)

Mubarak Tahir
Mubarak Tahir

Reputation: 207

For some reasons, android studio is not auto importing the library at the top, I suggest you do that manually.

add this as a top level declaration in TutorialFragment

import com.google.android.material.tabs.TabLayout

Upvotes: 0

Tuby
Tuby

Reputation: 3253

Error clearly says the TabLayout is null

Try changing

tabBar.setupWithViewPager(tutorialview.tutorialViewPager)

to

tutorialview.tabBar.setupWithViewPager(tutorialview.tutorialViewPager)

Upvotes: 2

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