The list view in Nativescript shows only the element separators.

I have a Nativescript-Angular code sharing project. I use two ListView of in a lazy loaded module. The lazy loaded module is structured so that when I navigate to this module from AppModule, I have a component that has a TabView element as the root element, as shown below.


Now every Router-page output shows a side-by-side component in TabView. These components have ListView as the root element, as shown below


Now, the problem I'm facing is when these two list views are displayed side by side. Sometimes the list views show nothing and sometimes only the second tab displays data while the first tab only shows the item separators, as shown below: –

Case 1 tab-1
enter the description of the image here

Case 1 tab 2
enter the description of the image here

Case 2 tab-1
Case 2-image-1

Case 2 tab 2
Case 2-image-2

Articles always have more than one item, but the problem persists.

I've tried using the function listview.refresh () but still not successful with that. I've also used ChangedDetectionStratergy.OnPush and called marquéForRefresh function when the data is received. I tried to use ObservableArray provided by Nativescript but I was a little confused using this and also I thought it was not available for the code share project.

I've been frustrated since yesterday and it looks like a Nativescript bug. Can you help to overcome it so that both tabs always display the data (knowing that arrays always have more than one element)?

General Topology – Scattered Separators in Nearly Zero Dimension Spray Sets

This is the continuation of my previous question (s) Separators scattered in the space of Erds @TarasBanakh answered. He showed that delimited dividers in Erdös spaces had a cardinality $ mathfrak c = | mathbb R | $and therefore are not scattered.

Now let's suppose $ X $ is almost zero-dimensional (AZD), which means $ X $ has a base of neighborhoods that are themselves intersections of clopen sets, and suppose that there is a point $ p $ such as $ X cup {p } $ is connected (and separable metrizable).

Question. Does each disperse separator of $ X cup {p } $ contain the point $ p $?

A set is scattered if each of its subsets has an isolated point (in the subspace topology).

My first thoughts

Suppose that there is a scattered $ S subseteq X cup {p } $ such as $ (X cup {p }) setminus S $ is not connected and $ p notin S $. Since $ S $ is scattered, there is a compactification (metizable) $ Y $ of $ X cup {p } $ who also has a countable separator $ p $.

We know that each AZD space fits into the entire Erdös space $ mathfrak E _c $. According to Lavrentiev's theorem, the homeomorphism of $ X $ in $ Y $ extends to a homeomorphism between a $ G_ delta $-together $ X subseteq mathfrak E_ c $ and one $ G_ delta $-all set of $ Y $. then $ X $ cup {p } is a complete connected set also with a missing dispersed separator $ p $ (and $ X $ is AZD).

According to some theorems about AZD spaces, we can see $ X $ as:

  • a dense ($ G_ delta $) subset of $ mathfrak E_c $;
  • dense ($ G_ delta $) subset of the end points of Lelek's range (and in fact $ X $ cup {p } should be in this fan);
  • a closed subset of the complete AZD space $ mathfrak E_c ^ omega $.

It is not clear for now how to reach a contradiction by using one of these facts.

General Topology – Scattered Separators in Erdös Space

Let $ X $ be the set of all the points $ ell ^ 2 $ with all the rational coordinates. $ X $ is known to be totally disconnected but $ X $ is not zero-dimensional. For example, the empty game does not separate the point $ langle 0,0,0, … rangle in X $ from the closed set $ {x in X: | x | geq 1 } $ because $ { | x |: x in A } $ is unlimited for each clopen game $ A subseteq X $.

L & # 39; together $ S: = {x in X: | x | = 1/2 } $ separate $ langle 0,0,0, … rangle $ and $ {x in X: | x | geq 1 } $. C & # 39; is, $ X setminus S $ is the union of two disjoint open sets, one containing $ langle 0,0,0, … rangle $and the other container $ {x in X: | x | geq 1 } $. Note that $ S $ There are no isolated points; $ overline {S setminus {s }} = S $ for each $ s in S $.

My questions are:

(1) Is there a closed dispersed separator between $ langle 0,0,0, … rangle $ and $ {x in X: | x | geq 1 } $? A set is scattered if each non-empty subset has an isolated point.

(2) Is there a point $ x in X $ and a closed set $ A subseteq X setminus {x } $ which can not be separated by a closed scattered ensemble?

(3) Repeat (2) for the full space $ Y $ made up of all the points of $ ell ^ 2 $ who only have irrational coordinates.

algorithms – Find all separators in a tree

Let a tree of N colored vertices in one of the colors 1 … N.

Let's call a separator edge if, when this edge is removed from the tree, all the vertices of each color remain connected.

The goal is to find all the separators in a tree in time O (N) and in memory O (N).

My first approach was to use FCB to find the LCA for all the vertices of each color, and then the separator was an edge that was not between an ACV and some vertices if the same color was used for any color , but I can. do not propose ideas to go further.