How to check changing collection?

shopify change collection from automatic to manual
how to remove a product from a collection shopify
mongodb change streams nodejs
mongodb collection last update time
pymongo detect changes
mongodb change stream performance
collections
shopify collection conditions

Depending on the number of items in the collection, I want to do certain actions.

For example

if i have 1 item in collection -> doFirstAction()
if i have 2 or more items in collection -> doSecondAction()
if i have 2 or more items in collection and deleted all instead one -> doSecondAction()

On this basis i need to check changing the list.

I found something similar: ObservableList. And it seems to solve my problem, but unfortunately I do not know how it can be used correctly.

In my class i need check this collection:

var viewModels: List<ConnectionViewModel> = emptyList()

UPDATE: With this answer i write smth like this:

var viewModels: ObservableList<ConnectionViewModel> = ObservableArrayList<ConnectionViewModel>()

And add listener on my collection:

fun setOnDataChange() {
    viewModels.addOnListChangedCallback(object :
        ObservableList.OnListChangedCallback<ObservableList<ConnectionViewModel>>() {
        override fun onChanged(sender: ObservableList<ConnectionViewModel>?) {}

        override fun onItemRangeRemoved(
            sender: ObservableList<ConnectionViewModel>?,
            positionStart: Int,
            itemCount: Int
        ) {
            showBiometricConfirmation = showConfirmation(itemCount)
        }

        override fun onItemRangeMoved(
            sender: ObservableList<ConnectionViewModel>?,
            fromPosition: Int,
            toPosition: Int,
            itemCount: Int
        ) {}

        override fun onItemRangeInserted(
            sender: ObservableList<ConnectionViewModel>?,
            positionStart: Int,
            itemCount: Int
        ) {
            showBiometricConfirmation = showConfirmation(itemCount)
        }

        override fun onItemRangeChanged(
            sender: ObservableList<ConnectionViewModel>?,
            positionStart: Int,
            itemCount: Int
        ) {}
    })
}

private fun showConfirmation(itemCount: Int): Boolean {
    return itemCount != 1
}

But i have some problem I need check the number in the collection. If number was 3 and after i delete 2, i also need to call doSecondAction(). but if collection number was 1, need to call doFirstAction()

First you should enable dataBinding in gradle, inside android{}

android {
    ......
    dataBinding {
        enabled = true
    }
}

Then, in your code create empty list:

   val list: ObservableList<String> = ObservableArrayList<String>()

You can set listener like this:

list.addOnListChangedCallback(object:ObservableList.OnListChangedCallback<ObservableList<String>>(){
            override fun onChanged(sender: ObservableList<String>?) {
                Log.d("Misha", "changed")
            }

            override fun onItemRangeRemoved(sender: ObservableList<String>?, positionStart: Int, itemCount: Int) {
                ...
            }

            override fun onItemRangeMoved(sender: ObservableList<String>?, fromPosition: Int, toPosition: Int, itemCount: Int) {
                ...
            }

            override fun onItemRangeInserted(sender: ObservableList<String>?, positionStart: Int, itemCount: Int) {
                ...
            }

            override fun onItemRangeChanged(sender: ObservableList<String>?, positionStart: Int, itemCount: Int) {
                ...
            }    
 })

You can add(remove) values like this, or with other methods:

 list.addAll(0, listOf("Misha", "Akopov"))

How to check if a collection has changed?, MongoDB 3.6 has a brand new feature called change stream that allows you to listen changes happening on your collections in real time. The� Changing properties of underlying objects does not in any way suggest the collection has changed. One way to achieve this behavior is to create a custom collection which will interrogate the object once added and register for the INotifyPropertyChanged.PropertyChanged event; it would then need to de-register appropriately when an item is removed.

One way is to use ViewModel + Observer pattern.

  1. ViewModel. We put the list that will be observed here
// SETTER
val _myList = MutableLiveData<MutableList<Item>>()

// GETTER
val myList: LiveData<MutableList<Item>> = _myList

init {

   _myList.value.add(item1)
   ... add remaining items

}

  1. Activity. We modify / set the list and observe the list changes.
mViewModel.myList.observe(this, Observer{

   // it == myList
   if (it.size == 1) doFirstAction()
   else if (it.size >= 2) doSecondAction()
   else if (it.size >= 2 && deleted all instead one) do second action

})

// MODIFY LIST
mViewModel._myList.value.remove(item2)
mViewModel._myList.value.add(item4)

There will be a lot of null check warning. And later on you might wanna make _myList private and do this

Edit collections - Android - Currents Help, Check the box, then tap Delete. See who's following your collection. On an Android phone or tablet, open the Currents app "" . At the bottom,� The agency may check the post office for a forwarding address. Also, major credit bureaus with their own collection agencies receive change-of-address information for each month from the U.S. Postal Service.

Resolve my problem with next solution:

Create next var:

private var quickConfirmMode: Boolean = false

And use it in my custom setter:

var viewModels: List<ConnectionViewModel> = emptyList()
    set(value) {
        quickConfirmMode = value.size == 1 && (field.size == 1 || field.isEmpty())
        field = value
    }

Solution: Where field is backing property, which save my value. More information about getters and setters you can read here. So in my custom setter i check my new and old value, then I set the value for quickConfirmMode.

Creating and modifying automated collections � Shopify Help Center, Enter a condition value. Tap the check mark to add the condition. Change the publish date� We can check our newly created collection by file option as shown below: In this way, we can create a collection. Now, the next question is how to ADD/EDIT/Remove in the collection. So, let’s understand this now. Add Collection. Just drag-drop textboxes, labels, and a button to add the data to the collection as shown below.

Manual collections � Shopify Help Center, You can't change an automatic collection to a manual collection. Instead, create a Check the products that you want to include in the collection. List of products� On the Site Collection Administrators page, click the arrow next to the site collection name, and then select Change Site Collection if the site collection you want is not already selected. If the site collection to which you want to add an administrator is listed, select the URL of the site collection, and then click OK .

How Collection Agencies Find You, The agency may check the post office for a forwarding address. Also, major credit bureaus with their own collection agencies receive change-of-address� To find out what you have in collections, you will need to check your latest credit reports from each of the 3 credit bureaus. Collection agencies are not required to report their account information to all three of the national credit reporting agencies. In fact, some collection agencies may choose not to report their accounts at all.

Control and change order of the collections list page (/Collections , To keep your theme up to date, check out this helpful document. below to specify which collections are included, and how to change their order on the page. Part of a debt collector’s job is to locate you. They’re trained to use various tactics to find people, those who are hiding and even those who aren’t. Unless you’re moving around a lot, changing your phone number often, and not giving your number to anyone, you probably won’t dodge debt collectors for very long.

Comments
  • in my case i need change var viewModels: List<ConnectionViewModel> = emptyList() on var viewModels: ObservableList<ConnectionViewModel> = ObservableArrayList<ConnectionViewModel>() ? And after this whole my logic with size of collection i need to insert in onChanged?
  • Yes, you will have listener on that list
  • sorry but i don't understan how i can see that my collection was changed? For example as it is possible to write down a condition that a pier the size of the collection was three and became one for example?
  • Please read this one, parametr descriptions developer.android.com/reference/android/databinding/…
  • This is about update content in collection. But I need to react to changes in the number of items in the collection itself