Android: View Visibility set to View.VISIBLE but View is not Visible

Issue

In my app (general construction described below), I have a timer, which the user can start by clicking an in-app button.
When the timer starts, a notification is shown. In the notification, there's a "STOP" button, which when clicked is supposed to open the app (if closed or killed) and then show a custom dialog.
The custom dialog is built of a bunch of views and a blur-background view.
There are two ways to open that dialog:

1. Clicking an in-app button triggers the method that opens this dialog.
2. Clicking the "STOP" button in the notification also triggers the same method (By calling a BroadcastReceiver that lives in the same fragment as the dialog, and in the BroadcastReceiver I call the method that opens the dialog - it all happens after the app opens (if it was closed or killed)).

The first method works - clicking the button opens the dialog when it's supposed to.
The second, however, opens the app but not the dialog (To clarify - opening the dialog means changing its views visibility to View.VISIBLE).

To check what goes wrong, I used a Toast message that shows the visibility of the dialog every time the method that opens the dialog gets called. The Toast message shows "VISIBLE", so that means the Views visibility is set to View.VISIBLE indeed - but the dialog is not shown, nor the blur-background.

General Construction: The app has multiple Fragments, stored inside a view pager, inside the MainActivity and the dialog lives in the main fragment.

Might Be Relevant: when clicking the notifications button, the app opens, but the notification panel stays fully opened. The Toast message shows behind the notification panel.
Also might be worth mentioning, that when I click the notification button while I didn't yet leave the app, the dialog pops up. Only after I leave the app and then come back (manually or by clicking the notification button) the dialog doesn't pop up.

dialog's XML: (stored inside of fragment_main.xml)

<com.google.android.material.circularreveal.CircularRevealFrameLayout
        android:id="@+id/dialog_container"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="invisible"
        app:layout_behavior="com.google.android.material.transformation.FabTransformationSheetBehavior">

    <com.google.android.material.card.MaterialCardView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:cardPreventCornerOverlap="true">

        <RelativeLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:padding="15.0dip">

            //Here is the content of the dialog, textviews and custom buttons

        </RelativeLayout>

    </com.google.android.material.card.MaterialCardView>

</com.google.android.material.circularreveal.CircularRevealFrameLayout>

dialog opening method:

private void openDialog() {
    //while "dialog" refers to the "dialog_container" in the dialog xml
    dialog.setVisibility(View.VISIBLE);
    fadeBlurIn(); //fades the blur-background view in
    dialog.setClickable(true);
}

calling the method in the BroadcastReceiver: (stored inside MainFragment.java)

private final BroadcastReceiver endTimerReceiver = new BroadcastReceiver() {
    @RequiresApi(api = Build.VERSION_CODES.M)
    @Override
    public void onReceive(Context context, Intent intent) {

            .
            .
            .

            boolean openDialog = {gets a boolean extra, works fine};
            if (openDialog){
                openDialog();
            }
        }

    }
};

this BroadcastReceiver is attached to this fragment and works fine.

Why doesn't the dialog show?
And how can I fix it?

Solution

Problem Solved

What was the issue all about?

The problem was when re-opening the app after closing or leaving it, the main-fragment was re-created, and with it a new blur-background and a new custom dialog.
The BroadcastReceiver was stored in the old main-fragment, and so it referred to the old views (the old blur and dialog views)
The old views' visibility has changed, but the new ones didn't, so the visibility state change wasn't visible to the user.

But that's not all. Later on, I discovered that in addition to all that, even if I refer to the right view and try to display it, it's not displaying, and I found another problem - I try to change its visibility state too early.

Solution

Solving it was quite simple.
All I had to do was make the blur-background and the custom dialog static, so they'll not re-create every time a main-fragment is created. Then Their visibility state changes were visible to the user.

And the solution for the second half of the problem was even easier - all I had to do is put the command calling the method to show the dialog inside a Runnable, running in delay by a Handler. 10 ms of delay has done the job.

Although this thread's issue is solved by now, this issue still isn't.

Note to self

A good habit is to think ahead, knowing what objects I should set static, so that stuff like this won't happen frequently

Answered By - Nitzan Daloomy