How to create an array of templates - ionic2

I need to create a timeline. For this I need cards repeating.
I already created and manage to show the template of the card I want.
But now I need to make this repeat... I do not have a BD right now, so first I'm creating the frontend of the application, so for now I only need to create a simple array that will repeat my template x times.
This is my HTML:
<ion-list>
<enviouTemplate [cardEnviou]="enviouCard" *ngIf="buttonClicked1"></enviouTemplate>
<recebeuTemplate [cardRecebeu]="recebeuCard" *ngIf="buttonClicked2"></recebeuTemplate>
</ion-list>
The father TS don't have any code right now, this is working purely by using the children TS directly to HTML.
How can I make the cards repeat?
The ngIf is there because there'll be two kind of cards, so don't mind that.
Thanks a lot!

I manage to make it work, right now its like this:
HTML:
<ion-list *ngFor="let card of cards">
<enviouTemplate [cardEnviou]="card" *ngIf="buttonClicked1"></enviouTemplate>
<recebeuTemplate [cardRecebeu]="card" *ngIf="buttonClicked2"></recebeuTemplate>
</ion-list>
Parent TS(only for test):
cards : any = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
But my question now is about something that I read, that its not a good practice to use ngFor inside ion-list.
So how should I build the html?
One thing to point, I need to use the ngIf, because I have two timelines that will show up only when a button is selected, and I see that the application don't accept ngFor and ngIf in the same element...

Related

Column-Packed RowColumn Class for Motif Library (C)?

I recently asked this question: Horizontally-Drawn RowColumn Class for Motif Library (C)?
In my previous question, I was having trouble getting the xmRowColumnWidgetClass to draw horizontally (row-by-row) instead of vertically (column-by-column). After playing around with it, figured out how to switch to horizontal drawing with the following snippet:
XmNorientation, XmHORIZONTAL,
So the code that creates the xmRowColumnWidgetClass instance now looks like this:
rowColumn = XtVaCreateManagedWidget("rowcolumn",
xmRowColumnWidgetClass,
parentWidget,
XmNnumColumns, 3,
XmNorientation, XmHORIZONTAL,
XmNpacking, XmPACK_COLUMN,
XmNspacing, 6,
NULL);
However, my new problem is that for some reason the XmNnumColumns field is now referring to the number of rows, rather than the actual number of columns. Before adding the XmNorientation, XmHORIZONTAL part, the xmRowColumnWidgetClass instance was drawing the objects from left-to-right but it stayed to 3 columns like it was supposed to. Now, it is staying to 3 rows, occasionally creating a horizontal scrollbar which I do not want. I only want vertical scrolling.
So I need the children of the xmRowColumnWidgetClass instance to be drawn horizontally from top to bottom, but I need it to only put a maximum of 3 per row and thus keep it confined within a certain width.
I tried playing around with the XmNnumColumns field, but things that worked with more children did not work for less children, and vice versa. Sometimes it made it 4 or 5 columns rather than 3, and sometimes it made it 2 columns with the 3rd column completely empty. I encountered many issues like this even when experimenting with things like using XmNpacking, XmPACK_TIGHT rather than XmNpacking, XmPACK_COLUMN and other stuff.
If someone is able to find the official documentation of the xmRowColumnWidgetClass and link it, that would be be greatly appreciated.
To anybody familiar with this library:
How do I create a xmRowColumnWidgetClass instance that draws horizontally (row-by-row) while keeping it to a certain number of columns?
It should be able to handle any number of children and add as many rows as it needs to in order to keep it as exactly 3 columns.
Another group of examples of this library:
https://github.com/spartrekus/Motif-C-Examples
https://github.com/spartrekus/Motif-C-Examples/blob/master/rowcol.c
XmRowColumn was designed to implement the top menubar and all the other menu classes... You are searching for a grid like widget, and so you have to use XmForm read the related question for that.
In short: try the WtTable widget
Longer explanation follows:
The behaviour of XmRowColumn regarding "columns" becoming "rows" when you choose a horizontal configuration is very unfortunate. The alternative of using XmForm instead of XmRowColumn for this purpose is feasible, but however it requires manually setting the children constraints, and even then, it's quite possible that you won't be able to achieve the automatic sizing implemented in XmRowColumn.
By searching today, I found the WtTable widget and it works fine for my purposes. It's "almost" as automatic as XmRowColumn and it doesn't require to set any constraints manually. I tried it in my Motif code, and works fine.
Note however that I said "almost" as automatic. The "almost" is because you need to specify the number of columns and rows, and you need to specify the column and row for each child widget. However, all of this can be automated: you can create a convenience function that internally manages counters for columns and rows, so that you pass a widget to such function and it puts it in the cell it belongs automatically: you can even make that function create a new row in the WtTable when it's needed.

C++ Undo Command / Reverse to previous state

I have a grid of randomly generated numbers of size gameSize (user input) which is contained within a vector of vectors. The user can enter two co-ordinates (x, y) so that it changes a number within the grid to a predefined value, which is "0".
So for example the user enters, X:0 Y:0 and:
{9, 7, 9}
{9, 6, 8}
{5, 1, 4}
becomes:
{0, 7, 9} <-- Changes position 0,0 to 0 (the predefined value)
{9, 6, 8}
{5, 1, 4}
I'm trying to figure out how to add an "undo" feature in which the user is prompted if they want to undo their selection or not, and if Yes then reverse the selection so that position 0,0 changes back to the original value (which is the value 9 in this example). How can I implement this? I understand I need to somehow record a previous grid state but have no clue how.
If you only want to be able to "undo" the last change, then you could simply make a copy, a backup of sorts, of the state before doing the change. Then if the user wants to "undo" the change then copy from the backup into the actual data.
For more levels of undo you could have a stack of copies.
If the data is large, then instead of copying the data for every change just store a copy of the actual change instead. Then when the user wants to "undo" you do the opposite of the change.
Example: If the user want to modify coordinates X,Y by Z, then store X, Y and Z. Then when doing undo you modify X,Y with -Z.
In object oriented languages you often find that people will use the command pattern to implement undo systems. Some people might say it's overkill but it is really quite flexible and doesn't take much boiler plate to get started.
The general idea is that you create an interface, with the methods execute() and undo(). You then you can create a whole slew of other classes that implement that interface and that know how do specific actions (e.g., in your example change position) and how to undo them. You then just need to keep track of commands that you have executed by putting them on a stack, and when you need to undo just pop them from the stack and call undo().
Here is a good resource for learning about the command pattern and design patterns in general.

Foundation source ordering confusion

I have a row setup like so:
<div class="row">
<div class="small-12 small-push-12 large-6 columns">
<!-- Content -->
</div>
<div class="small-12 small-pull-12 large-6 columns">
<!-- Content -->
</div>
</div>
Basically, I want the second column to be pulled before the first column when the screen is small, but keep it at proper order for large screens.
What am I doing wrong here? The document reflows like it always does.
Also, I do realize I can just reverse the order in the HTML itself and it'll work, but just curious if it's possible to make it work this way.
Your question prompted me to look at Foundation’s SCSS source code to see how the grid was implemented since like you I was having trouble getting my columns to shift as I wanted. In the time spent finding an answer I’ve now forgotten what I’d needed to find out originally but having gained insight as to how the grid works I know it will now be much easier to use and I’ll feel more confident that my work is correct. I’ll try to provide some of that insight here.
The simple answer to your question is, No, you can’t make Foundation swap a block of columns in the way you’ve done it. [I’ll call them columns as opposed to grid columns that refer to Foundation’s (usually 12) base columns.] Assuming it might have worked I’d say that the code you wrote would be correct. The actual reason it fails to work is because *there are no 12 column push or pull classes defined in Foundation for small, medium, large or any media size range." Thus, when the media screen size is "small" (in your case) the push and pull classes are silently ignored by CSS and you end up with two columns on two rows in the original order.
The general rule is that you can’t push or pull columns from one row to another; you can only move them along the same row. After seeing that I reread your question which began, "I have a row setup like so…" But that’s not true since the intention is to produce two rows. That one can create multiple rows with one column(s) definition is, I think, just a side effect of how CSS floats work.
Here’s what happens (excuse me for anthropomorphizing the CSS attributes…it's just easier to talk about them as "doing something to something" and often seems to be the best way to clearly understand what's happening):
For every column you specify, it’s width is determined using the current grid column width (plus some "gutter" for spacing) multiplied by the specified number of grid columns from the class name used (large-6, small-2, etc.). Since they have been given the float attribute they are then lined up one against the next starting at the beginning of the row. If there is not enough room on one row to display all the columns the line of columns is split and continues on the "line" below, and so on; those that don't fit are moved to the next row (and so on). Without other classes specified each column will be displayed in this initial position. This is how multiple rows can be formed from one column(s) definition.
When you add push and pull classes the CSS right and left attributes are added to those described above. The offset determined by the specified push or pull class is used to calculate the relative shift which is used to reorder columns if necessary. But the left and right CSS attributes know nothing about where these column-blocks have come from or that there is any row but the one they work on. So each column is moved along the line where it was initially placed and if the amount of shift moves the column outside of the row boundary it will be placed (or partially placed) to the left or right of the row (and possibly out of sight). That’s the reason that your proposed process won't work in general though in your case, as mentioned above, you used a class that wasn't defined (small-push-12) and got a different effect. If you play around a bit with the lower numbered push and pull classes (1 through 11) you can see more clearly how the columns are pushed part way off a row. (the way it is currently done by Foundation, at least) and why I now think (since at first I thought it might be possible myself) that being able to create multiple rows in the base case is a beneficial "side effect" of how CSS happens to work.
For anyone wanting to improve their CSS understanding or who uses Foundation, I highly recommend taking some time to work through one or more of the features that Zurb has implemented in the framework. I find that the SCSS definitions are well designed and cleanly coded (though perhaps not to everyone’s liking since, IMHO, CSS coding opinions seem to be as inflammatory as Mac/Windows opinions and often evoke the same fervor when expressed).
Found the solution in a separate thread! Start with the order you want in the source for mobile, then use the push/pull classes to bend it around for the LARGER sizes. In other words, approach it from the opposite end.
Change order for Foundation small-12 column

Setting the size of a GTKEventBox

I've got a GtkHBox with 2 items. Inside that, on the left, I have a GtkHBox with 4 items. The first two are GtkEventBox's, followed by a GtkHScale and finally a GtkLabel.
The two GtkEventBox's each contain a GtkVBox with two items, an image and a label (using the GtkEventBox so that I can catch click events on the image). Unfortunately, I can't seem to figure out how to set the width for them. Currently, it looks like this:
But I want the Select and Pan sections to be much narrower. Any suggestions?
Make sure to pack the event boxes into your GtkHBox with the expand and fill parameters set to false.

Splitting a list based on another list values in Mathematica

In Mathematica I have a list of point coordinates
size = 50;
points = Table[{RandomInteger[{0, size}], RandomInteger[{0, size}]}, {i, 1, n}];
and a list of cluster indices these points belong to
clusterIndices = {1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1};
what is the easiest way to split the points into two separate lists based on the clusterIndices values?
EDIT:
The solution I came up with:
pointIndices =
Map[#[[2]] &,
GatherBy[MapIndexed[{#1, #2[[1]]} &, clusterIndices], First],
{2}];
pointsByCluster = Map[Part[points, #] &, pointIndices];
It there a better way to do this?
As #High Performance Mark and #Nicholas Wilson said, I'd start with combining the two lists together via Transpose or Thread. In this case,
In[1]:= Transpose[{clusterIndices, points}]==Thread[{clusterIndices, points}]
Out[1]:= True
At one point, I looked at which was faster, and I think Thread is marginally faster. But, it only really matters when you are using very long lists.
#High Performance Mark makes a good point in suggesting Select. But, it would only allow you to pull a single cluster out at a time. The code for selecting cluster 1 is as follows:
Select[Transpose[{clusterIndices, points}], #[[1]]==1& ][[All, All, 2]]
Since you seem to want to generate all clusters, I'd suggest doing the following:
GatherBy[Transpose[{clusterIndices, points}], #[[1]]& ][[All, All, 2]]
which has the advantage of being a one liner and the only tricky part was in selecting the correct Part of the resulting list. The trick in determining how many All terms are necessary is to note that
Transpose[{clusterIndices, points}][[All,2]]
is required to get the points back out of the transposed list. But, the "clustered" list has one additional level, hence the second All.
It should be noted that the second parameter in GatherBy is a function that accepts one parameter, and it can be interchanged with any function you wish to use. As such, it is very useful. However, if you'd like to transform your data as your gathering it, I'd look at Reap and Sow.
Edit: Reap and Sow are somewhat under used, and fairly powerful. They're somewhat confusing to use, but I suspect GatherBy is implemented using them internally. For instance,
Reap[ Sow[#[[2]], #[[1]] ]& /# Transpose[{clusterIndices, points}], _, #2& ]
does the same thing as my previous code without the hassle of stripping off the indices from the points. Essentially, Sow tags each point with its index, then Reap gathers all of the tags (_ for the 2nd parameter) and outputs only the points. Personally, I use this instead of GatherBy, and I've encoded it into a function which I load, as follows:
SelectEquivalents[x_List,f_:Identity, g_:Identity, h_:(#2&)]:=
Reap[Sow[g[#],{f[#]}]&/#x, _, h][[2]];
Note: this code is a modified form of what was in the help files in 5.x. But, the 6.0 and 7.0 help files removed a lot of the useful examples, and this was one of them.
Here's a succinct way to do this using the new SplitBy function in version 7.0 that should be pretty fast:
SplitBy[Transpose[{points, clusterIndices}], Last][[All, All, 1]]
If you aren't using 7.0, you can implement this as:
Split[Transpose[{points, clusterIndices}], Last[#]==Last[#2]& ][[All, All, 1]]
Update
Sorry, I didn't see that you only wanted two groups, which I think of as clustering, not splitting. Here's some code for that:
FindClusters[Thread[Rule[clusterIndices, points]]]
How about this?
points[[
Flatten[Position[clusterIndices, #]]
]] & /#
Union[clusterIndices]
I don't know about 'better', but the more usual way in functional languages would not be to add indices to label each element (your MapIndexed) but instead to just run along each list:
Map[#1[[2]] &,
Sort[GatherBy[
Thread[ {#1, #2} &[clusterIndices, points]],
#1[[1]] &], #1[[1]][[1]] < #2[[1]][[1]] &], {2}]
Most people brought up in Lisp/ML/etc will write the Thread function out instantly is the way to implement the zip ideas from those languages.
I added in the Sort because it looks like your implementation will run into trouble if clusterIndices = {2[...,2],1,...}. On the other hand, I would still need to add in a line to fix the problem that if clusterIndices has a 3 but no 2, the output indices will be wrong. It is not clear from your fragment how you are intending to retrieve things though.
I reckon you will find list processing much easier if you refresh yourself with a hobby project like building a simple CAS in a language like Haskell where the syntax is so much more suited to functional list processing than Mathematica.
If I think of something simpler I will add to the post.
Map[#[[1]] &, GatherBy[Thread[{points, clusterIndices}], #[[2]] &], {2}]
My first step would be to execute
Transpose[{clusterIndices, points}]
and my next step would depend on what you want to do with that; Select comes to mind.