来自 viewpager2 和我的父片段的 SharedViewModel

问题描述

所以，我有一个片段，我们称之为片段 A，我需要它作为我的 sharedviewmodel 的主要宿主.

So, I have one fragment, lets call it Fragment A, in which I need it to be the main host of my sharedviewmodel.

所以我是这样的

class FragmentA:Fragment() {

 private val model: SharedViewModel by viewModels()

}

现在，在 Fragment A 中，我设置了 viewpager2 适配器

Now, inside Fragment A, I set viewpager2 Adapter

private fun setupViewPagerWithTabLayout(
        productList: MutableList<Producto>,
        drinkList: MutableList<Producto>
    ) {
        val fragmentList = listOf(
            FragmentProducts.newInstance(productList),
            FragmentProducts.newInstance(drinkList))

        viewPager2.adapter = MyViewPageAdapter(requireActivity(),fragmentList)
        val tabLayoutMediator = TabLayoutMediator(tabLayout, viewPager2,
            TabLayoutMediator.TabConfigurationStrategy { tab, position ->

                when (position) {
                    0 -> {
                        tab.text = "Option1"
                    }
                    1 -> {
                        tab.text = "Option2"
                    }
                }

            })
        tabLayoutMediator.attach()
    }

在这里我实例化了我的 FragmentProduct，它位于视图页面的 Fragment A 中，但我的适配器需要一个 FragmentActivity

Here I instantiate my FragmentProduct which is inside Fragment A in a viewpager, but my adapter needs a FragmentActivity

class MyViewPageAdapter(fragmentActivity: FragmentActivity,private val fragmentList: List<FragmentProducts>) :
    FragmentStateAdapter(fragmentActivity) {

    override fun getItemCount(): Int {
        return fragmentList.size
    }

    override fun createFragment(position: Int): Fragment {
        return fragmentList[position]
    }
}

所以，从 FragmentA 中包含的 FragmentProducts，我需要与这个视图模型共享数据，但是当我这样做是为了将数据从这个 FragmentA 共享到 FragmentA

So, from FragmentProducts that is contained inside FragmentA, I need to share data with this viewmodel, but when I do this to share data from this fragment to FragmentA

class FragmentProducts:Fragment(){

    private val model: SharedViewModel by viewModels ({requireParentFragment()})

}

我收到以下错误

java.lang.IllegalStateException: Fragment FragmentProducts{6953da8}(3a2f5cbb-113d-4ed2-8f85-56e04fcea356) f0} 不是子片段，它直接附在com.example.MainActivity@dcc2679

java.lang.IllegalStateException: Fragment FragmentProducts{6953da8} (3a2f5cbb-113d-4ed2-8f85-56e04fcea356) f0} is not a child Fragment, it is directly attached to com.example.MainActivity@dcc2679

所以，这告诉我 FragmentProducts 引用了我的 MainActivity，这就是逻辑，因为适配器的实例在 FragmentActivity 需要 requireActivity()

so , this is telling me that FragmentProducts references to my MainActivity, and thats logic because the instance of the adapter takes requireActivity() for FragmentActivity at

viewPager2.adapter = MyViewPageAdapter(requireActivity(),fragmentList)

所以，我需要传递我的 FragmentA 而不是 requireActivity() 作为该 viewpager 片段的主机，但是在我的 ViewPagerAdapter 中，我不能传递 FragmentStatePagerAdapter 或其他东西来传递我的 FragmentA 作为该 viewpager 的上下文

So, I need to pass instead of requireActivity() my FragmentA as the host of this viewpager fragment but at my ViewPagerAdapter, I cant pass FragmentStatePagerAdapter or something else to pass my FragmentA as the context for that viewpager

由于我使用 viewpager2，有没有办法让 FragmentA 托管 FragmentProducts viewpager，这样我就可以像这样在我的 FragmentProducts 中获取它

Since Im using viewpager2, is there a way to let FragmentA host FragmentProducts viewpager so I can get it in my FragmentProducts like this

private val model: SharedViewModel by viewModels ({requireParentFragment()})

谢谢

推荐答案

你正在使用 FragmentStateAdapter(fragmentActivity).不要那样做.将您的父 Fragment 传递给 MyViewPageAdapter 并将 that 传递给 FragmentStateAdapter.

You're using FragmentStateAdapter(fragmentActivity). Don't do that. Pass your parent Fragment to MyViewPageAdapter and pass that to FragmentStateAdapter.

class MyViewPageAdapter(
    parentFragment: Fragment,
    private val fragmentList: List<FragmentProducts>
) : FragmentStateAdapter(parentFragment) {

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