Drag and drop divs using AngularJS - javascript

I'm creating a simple task manager where tasks are regrouped by steps. Therefore, many steps can have many tasks. Currently, I have my angularJS model mapped properly. What I want to do right now is to be able to reorder the divs representing the steps.
For example, if I have three steps named 1,3,2 I want to be able to drag the step 2 and move it above step 3 therefore putting them in the order 1,2,3. To do so, I would have to modify my angularJs model accordingly.
What I have currently, is that the ui is responding, I can see the step changing positions, but my the array containing all the steps stays in the same order... Is there a way to reorder this array or at least a way to get the new position of the step ?
http://plnkr.co/edit/bjsgQz?p=preview

You may want to consider using ui-sortable; I've used it on one of my own projects for allowing drag-and-drop reordering, and it's worked rather well. I should point out that it does have a dependency on JQuery/JQueryUI (for the sortable widget), but it was worth it for us.

Related

d3 - nested selections/sub-item update issue

I'm getting used to d3, but seem to be having trouble with more advanced structures. I'm fairly sure there's some subtlety or concept I am not fully appreciating. I want to be able to mirror a changing hierarchical data structure with a changing hierarchical element structure.
My data structure is 3 groups, each with 3 items. Each group and item has a unique key, extracted using a key function in the data() call.
I build the structure, and I can remove a top-level item; .exit().remove() works just fine on that selection. BUT, modifying or removing any sub-item is simply not reflected in the generated element structure.
Full (non-)working jsFiddle here!: http://jsfiddle.net/eu95R/2/, and the all-important enticingly beautiful screenshot:
The problem is that your definition of groups is using svg.enter() and the subselection is made on groups. That is, you're not seeing a change because groups in this case is empty (no enter selection for the SVGs) and therefore there's no subselection.
To fix, simply do the subselection based on e.g. svg (there are a number of ways to fix this -- not saying that this is necessarily the best one). As you are appending the elements to a g within the SVG, the selector would be svg.selectAll("g").selectAll("text.item")....
Complete demo here.

Place the same dojo datagrid in multiple places

Is it possible to place the same dojo data grid twice (or even more) on the same page? I have a Tab container and I need to show the grid inside at least two of the tabs. Is it as easy as modifying grid.placeAt("gridDiv");?
Much as you can only put one DOM node in one place at the same time, you can only put one widget in one place at the same time. If you need multiple grids that are the same, you’ll need to create multiple instances of the grid.

Sorting a list without a counter

This is currently just conseptual, but it bothers my brain.
If I have a list of items - in my mind it's a HTML/JS implementation, but that's just because I'm a visual thinker ;)
I want to use drag and drop to sort this list, with the aim of storing the new order when I'm done. Is there a way to do this without numbering the items, and then updating the number of the dropped item + every single item that follows it? Isn't that very inefficient?
As far as performance goes, changing the numbering of the elements is nothing next to actually rendering the transition (while you're dragging an element), so no, it's not inefficient.
You can use a doubly linked list in order to minmize the amount of operations needed to change the order of the collection.
I would recommend using a JavaScript framework to do the job.
KnockoutJS should fit your needs (from the website):
Knockout is a JavaScript library that helps you to create rich, responsive display and editor user interfaces with a clean underlying data model. Any time you have sections of UI that update dynamically (e.g., changing depending on the user’s actions or when an external data source changes), KO can help you implement it more simply and maintainably.
If you left gaps in the numbers, you could probably do it efficiently -- for instance, let the first element be 10, the second be 20, the third 30, etc. Then when you drag something in front of the second one and after the first, call it 15 (or something).
Rather than incrementing numbers every time, you'd only have to do it if you ran out of space. At the end, you could just order the objects by lowest number.
Not including any code here, because this is a conceptual question.
You have to have a number for every element in the list anyway, since they have to have a Total Ordering among themselves to be represented as a list.
If you don't expect the number of elements in the list to be large, a Bubble Sort should work very well for you.

How to render many ExtJS trees using a single data store

First of all, I am novice in ExtJS
I am working on Ext 4 Tree since few days.
The requirement is such that I want to display 3-4 representation of same tree at the same time. I want to do this using single data store.
Tree 1 will show all nodes without checkboxes
Tree 2 will show all nodes with checkboxes
Tree 3 will show only parent nodes (folders) and no leaf nodes (files)
I tried to do these using same data store but expanding/collapsing of one tree results into inconsistently expanding/collapsing of other. Also for checkbox, I have to denibe "checkbox: true/false" in data store which I have no idea how to control in Ext.
Please help me. It will be much help if there already an example around.
The main issue here is - you have just one copy of the store and all your trees are subscribed to this store events, so when something is fired by the store all trees react to that. And btw, same applies if you want for example to show couple different grids using same store.
If you need to have different behavior for each control you need to either constantly subscribe/unsubscribe from store events in each tree (depend on which one is focused right now) or more simple solution - to clone store and have individual copy for each tree.

Can anyone recommend a well performing interface to allow the user to organize a large number of items in HTML?

Currently for "group" management you can click the name of the group in a list of available groups and it will take you to a page with two side by side multi-select list boxes. Between the two list boxes are Add and Remove buttons. You select all the "users" from the left list and click 'Add' and they will appear in the right list, and vice versa. This works fairly well for a small amount of data.
The problem lies when you start having thousands of users. Not only is it difficult and time consuming to search through (despite having a 'filter' at the top that will narrow results based on a string), but you will eventually reach a point where your computer's power and the number of list items apex and the whole browser starts to lag horrendously.
Is there a better interface idea for managing this? Or are there any well known tricks to make it perform better and/or be easier to use when there are many 'items' in the lists?
Implement an Ajax function that hooks on keydown and checks the characters the user has typed into the search/filter box so far (server-side). When the search results drop below 50, push those to the browser for display.
Alternatively, you can use a jQuery UI Autocomplete plugin, and set the minimum number of characters to 3 to trigger the search. This will limit the number of list items that are pushed to the browser.
I would get away from using the native list box in your browser and implement a solution in HTML/CSS using lists or tables (depending on your needs). Then you can use JavaScript and AJAX to pull only the subset of data you need. Watch the user's actions and pull the next 50 records before they actually get to them. That will give the illusion of all of the records being loaded at runtime.
The iPhone does this kind of thing to preserve memory for it's TableViews. I would take that idea and apply it to your case.
I'd say you hit the nail on the head with the word 'filter'. I'm not the hugest fan of parallel multi-selects like what you are describing, but that is almost beside the point, whatever UX element you use, you are going to run into a problem given thousands of items. Thus, filtering. Filtering with a search string is a fine solution, but I suspect searching by name is not the fastest way to get to the users that the admin here wants. What else do you know about the users? How are they grouped.
For example, if these users were students at a highschool, we would know some meta-data about them: What grade are they in? How old are they? What stream of studies are they in? What is their GPA? ... providing filtering on these pieces of metadata is one way of limiting the number of students available at a time. If you have too many to start with, and it is causing performance problems, consider just limiting them, have a button to load more, and only show 100 at a time.
Update: the last point here is essentially what Jesse is proposing below.

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