Problem with creating secondary constructor kotlin

Question

Can someone explain me why I cannot create empty secondary construcor in my class? I wanna TEST it but I need to create a instance of class to use the methods from, but my class need a parametr to create it. I thought to create a scecondary constructor but when I'm trying it makes a error "There's a cycle in the delegation calls chain". Excatly I wanna use it on this @TEST below but when I'm trying to create instance of Adapter class I must put there also (FragmentManager) inside. Any ideas?

class Adapter(sFM: FragmentManager) : FragmentPagerAdapter(sFM, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) {

    constructor() : this()

    private val pFragmentList = ArrayList<Fragment>()
    private val pFragmentTitle = ArrayList<String>()

    override fun getCount(): Int = pFragmentList.size

    override fun getItem(position: Int): Fragment = pFragmentList[position]

    override fun getPageTitle(position: Int): CharSequence = pFragmentTitle[position]

    fun addFragment(fm: Fragment, title: String) {
        pFragmentList.add(fm)
        pFragmentTitle.add(title)
    }
}

@Test
fun `create instance of class Adapter`() {
        var adapter = Adapter().addFragment()
}

Jakoss · Accepted Answer · 2021-09-13 14:10:39Z

3

There is no FragmentPagerAdapter with empty constructor. Basically, what your code is trying to compile, is to do constructor that calls itself. If you want to use base class constructor you need to use super instead of this. But still, you won't find such constructor in base class. You always have to pass some FragmentManager

answered Sep 13, 2021 at 14:10

Jakoss

5,3342 gold badges30 silver badges41 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Szymon Over a year ago

So right now how can I call to Adapter class from my @Test function ? I wanna test function "addFragment" for example. How can I do it ?

Jakoss Over a year ago

If you really want to do UnitTests of adapter - just mock FragmentManager, for example with the mockk library. The proper way would be to do it as instrumented tests (on emulator) or using robolectric library

Collectives™ on Stack Overflow

Problem with creating secondary constructor kotlin

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related