How can I hide a fragment using supportFragmentManager?

Question

Here's my attempt:

private inline fun FragmentManager.inTransaction(func: FragmentTransaction.() -> FragmentTransaction) {
        beginTransaction().func().addToBackStack(null).commit()
    }

private fun AppCompatActivity.addFragment(fragment: Fragment, frameId: Int){
        supportFragmentManager.inTransaction { add(frameId, fragment) }
    }

private fun AppCompatActivity.showFragment(fragment: Fragment) {
        supportFragmentManager.inTransaction{show(fragment)}
    }

private fun showFragmentView(fragment: Fragment){

        // Hide the current Fragment
        if (supportFragmentManager.fragments.isNotEmpty()) {
            val currentFragment = supportFragmentManager.fragments.last()
            if (currentFragment != null) {
                supportFragmentManager
                        .beginTransaction()
                        .hide(currentFragment)
                        .commit()
            }
        }

        // Add or Show
        if (!fragment.isAdded) {
            addFragment(fragment, sendFragFrame.id)
        } else {
            showFragment(fragment)
        }
    }

It properly adds the fragment to the frame, but when I attempt to hide it nothing happens, it's stays visible and the second fragment cannot be seen. Can someone explain why this is happening?

`val currentFragment = supportFragmentManager.fragments.last()` there is no guarantee that this is true. — EpicPandaForce, Aug 14 '19 at 23:45

score 1 · Answer 1 · answered Aug 15 '19 at 05:44

It is not good practice (and most likely won't work) to access fragments in this way.

  if (supportFragmentManager.fragments.isNotEmpty()) {
            val currentFragment = supportFragmentManager.fragments.last()
            if (currentFragment != null) {
                supportFragmentManager
                        .beginTransaction()
                        .hide(currentFragment)
                        .commit()

You should add fragments with a tag and get the fragment by tag when you want to remove it and then do your transaction.

See the comments on this for more: How do I get the currently displayed fragment?

score 0 · Answer 2 · answered Aug 15 '19 at 17:03

0

Well embarrassingly my problem was that I had inadvertently swap my layout in Fragment2 with the layout for Fragment1...so it WAS working, but because they shared a layout you couldn't see it visually. I'd delete this post if I could, but I'll leave it here as tribute to my shame as a developer.

answered Aug 15 '19 at 17:03

szaske

1,887
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Again, I would not use this method though. It could lead to problems your users will run into. – Richard Dapice Aug 19 '19 at 02:50

How can I hide a fragment using supportFragmentManager?

2 Answers2