UnityDynamicScrollRect

An optimized approach to lists with dozens of elements.

How to use

you can find a pratical example inside this repository in DynamicScrollScene scene

1 - Create a class to store all the information that each element of the list will need.

public class ExampleData
{
      public int postId;
      public int id;
      public string name;
      public string email;
      public string body;
}

2 - Create a class that extends DynamicScrollObject<ExampleData> and implement its abstract members (make sure to call base.updateScrollObject(item, index);) and set the object width and height in currentWidth and currentHeight.

public class ExampleDynamicObject : DynamicScrollObject<ExampleData>
{
  public override float currentHeight { get; set; }
  public override float currentWidth { get; set; }

  private Text idText;
  private Text nameEmailText;
  private Text bodyText;

  public void Awake()
  {
    currentHeight = GetComponent<RectTransform>().rect.height;
    currentWidth = GetComponent<RectTransform>().rect.width;

    idText = transform.Find("PostId").GetComponent<Text>();
    nameEmailText = transform.Find("NameEmail").GetComponent<Text>();
    bodyText = transform.Find("Body").GetComponent<Text>();         
  }

  public override void updateScrollObject(ExampleData item, int index)
  {
    base.updateScrollObject(item, index);

    idText.text = item.id.ToString();
    nameEmailText.text = string.Format("{0} ({1})", item.name, item.email);
    bodyText.text = item.body;
  }
}

3 - Create a class to initiate the DynamicList (use DynamicScrollRect instead of ScrollRect)

public class ExampleScroll : MonoBehaviour
{
  public DynamicScrollRect verticalScroll;
  public GameObject referenceObject;

  private DynamicScroll<ExampleData, ExampleDynamicObject> mVerticalDynamicScroll = new DynamicScroll<ExampleData, ExampleDynamicObject>();

  public IEnumerator Start()
  {
    WWW www = new WWW(@"https://jsonplaceholder.typicode.com/comments");
    yield return www;
    var data = JsonHelper.getJsonArray<ExampleData>(www.text);

    mVerticalDynamicScroll.spacing = 5f;
    mVerticalDynamicScroll.Initiate(verticalScroll, data, 0, referenceObject);
  }      
}

DynamicScroll<T, T1> public overview

Properties

name	type	description
spacing	float	Value that represent the spacing between elements of the list
centralizeOnStop	bool	If the list should centralize the closest element to the center of the viewport after stop moving
objectPool	readonly Pooling < T1 >	The elements of the list
OnDragEvent	Action < Vector2 >	Event that triggers whenever the user scrolls the list, the parameter represent the velocity of the drag
OnBeginDragEvent	UnityEvent < PointerEventData >	Event that triggers in the first frame of dragging
OnEndDragEvent	UnityEvent < PointerEventData >	Event that triggers in the last frame of dragging

Methods

dynamicScroll.Initiate

• Description: Initiate the scroll rect with objReference objects applying infoList data.

• Parameters:

name	type	description
scrollRect	ScrollRect	a reference to the scroll rect
infoList	T[]	the list with the data information
startIndex	int	the item of index startindex will be the first element of the list
objReference	GameObject	a reference of the object that will be inside the list
createMoreIfNeeded	bool	if the list needs more itens, it will create more if createMoreIfNeeded == true
forceAmount	int?	if setted, it will force forceAmount objects to be created at start

dynamicScroll.ChangeList

• Description: Change the current list of the scroll rect.

• Parameters :

name	type	description
infoList	T[]	the list with the data information
startIndex	int	the item of index startindex will be the first element of the list. If -1, the current index will be setted.
resetContentPosition	bool	reset list position

dynamicScroll.RefreshPosition

• Description: Repaint the whole scroll rect. This is useful if any item inside the scroll rect changes the size (currentWidth and currentHeight).

dynamicScroll.ToggleScroll

• Description: Enable or Disable the ability to scroll the list.

• Parameters :

name	type	description
active	bool	enable or Disable the ability to scroll the list

dynamicScroll.CanMove

• Description: Returns true if all directions send thro parameter are available.

• Parameters :

name	type	description
directions	ScrollDirection	Enum flag with all the directions you want to know if are available

dynamicScroll.MoveToIndex

• Description: Tweens the content to centralize the object of index specified in the parameters.

• Parameters :

name	type	description
i	int	Index of the element to be centralized
totalTime	float?	Total time to the animation happen (if you choose to input this value, the next one will be ignored)
timePerElement	float?	This value will be multiplied by the difference between the current centralized element and the target element to get the totalTime

dynamicScroll.GetCentralizedObject

• Description: Returns the closest element to the center of the viewport.

dynamicScroll.GetLowest

• Description: Returns the most left (if horizontal scroll) or most bottom (if vertical scroll) T1 object.

dynamicScroll.GetHighest

• Description: Returns the most right (if horizontal scroll) or most upper (if vertical scroll) T1 object.