android: how do I check if dialogfragment is showing

I launch my dialog fragment using

FragmentTransaction ft =
getFragmentManager().beginTransaction();
MyDialogFragment dialog = new MyDialogFragment()
dialog.show(ft, "dialog");

then to get a handle on it I do 

Fragment prev = getFragmentManager().findFragmentByTag("dialog");

but once I get prev, how do I check if it is showing?

Back Story

My problem is that my looping code keeps launching the dialog again and again. But if the dialog is already showing, I don't want it to launch again. This back story is just for context. The answer I seek is not: "move it out of the loop."

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最佳答案

simply check if it's null

if(prev == null)
//There is no active fragment with tag "dialog"
else
//There is an active fragment with tag "dialog" and "prev" variable holds a reference to it.

Alternatively, you could check the activity the fragment prev is currently associated with, however, make sure you ask that after you make sure it's not null or you'll get a NullPointerException. Like this:

if(prev == null)
//There is no active fragment with tag "dialog"
else
if(prev.getActivity() != this) //additional check
//There is a fragment with tag "dialog", but it is not active (shown) which means it was found on device's back stack.
else
//There is an active fragment with tag "dialog"
小开

I added this to be inside my custom dialog fragment, so I don't have to worry about any logic on the outside. Override the show() and onDismiss() methods, with a boolean shown field:

  private static boolean shown = false;


@Override
public void show(FragmentManager manager, String tag) {
if (shown) return;


super.show(manager, tag);
shown = true;
}


@Override
public void onDismiss(DialogInterface dialog) {
shown = false;
super.onDismiss(dialog);
}

If you want to check whether it is shown or not, you can create a getter for the shown boolean.

小开 
 if (dialogFragment != null
&& dialogFragment.getDialog() != null
&& dialogFragment.getDialog().isShowing()
&& !dialogFragment.isRemoving()) {
//dialog is showing so do something
} else {
//dialog is not showing
}

UPDATE: team can you also try the below call, i think it will work logically:

dialogFragment.isResumed

that should mean its in the foreground displaying if im not mistaken.

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Kotlin style:

private fun showDialog(dialogFragment: DialogFragment, tag: String) {
supportFragmentManager.findFragmentByTag(tag).let { fragment ->
fragment ?: let {
supportFragmentManager.beginTransaction().let { transition ->
dialogFragment.show(transition, tag)
}
}
}
}
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100% Uptime

class ProgressDialogFragment : DialogFragment() {


companion object {
private val TAG = this::class.simpleName
}


lateinit var dialogFragmentManager: FragmentManager
 

fun showDialog() {
dialogFragmentManager.apply {
if (findFragmentByTag(TAG) == null) show(this, TAG) else return
}
}


}


lateinit var progressDialog: ProgressDialogFragment

Init: 💉

class MainActivity : AppCompatActivity() {


override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
   

initProgressDialog(supportFragmentManager)
}


fun initProgressDialog(fragmentManager: FragmentManager){
progressDialog = ProgressDialogFragment().apply {
dialogFragmentManager = fragmentManager
}
}

Use { progressDialog.showDialog() } everywhere 😎


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