Loop Scroll Rect Documentation

Cells used in the loop scroll rect must meet two requirements:

1. Layout Properties: Cells need preferred width and height for layout calculation. The easiest way is to attach a Layout Element component and set the preferred width and height.
2. Index Callback: Each cell must have a script attached that implements a method with the signature void ScrollCellIndex (int idx) to receive its index updates.

You can install the package using OpenUPM or via the Unity Package Manager using a Git URL.

Using OpenUPM:

openupm add me.qiankanglai.loopscrollrect

Using Unity Package Manager: Add package from git URL: https://github.com/qiankanglai/LoopScrollRect.git

To implement a basic loop scroll rect, you should follow these steps:

1. Provide Cells: Implement the LoopScrollPrefabSource interface to provide different cells. This is highly recommended for using a cache pool.
2. Provide Data: Implement the LoopScrollDataSource interface to provide data for a specified cell.
3. Handle Variable Sizes (Optional): If your cells have different sizes, implement LoopScrollSizeHelper to provide precise cell sizes.

For the simplest implementation reference, see InitOnStart.cs in the repository.

The following methods are available for controlling scroll position and testing refill logic:

Scroll Control

• ScrollToCell: Scrolls to a specified item and offset with a given speed.
• ScrollToCellWithinTime: Scrolls to a specified item and offset over a specific duration.

Refill Testing

• GetFirstItem: Returns the index and offset of the first visible item.
• Refill (Test mode): Clears and refills items from the start using a specified first item and offset.
• GetLastItem: Returns the index and offset of the last visible item.
• RefillFromEnd (Test mode): Clears and refills items from the end using a specified last item and offset.

Use these methods to manage the content of the scroll rect:

• Clear: Clears existing items and sets the total count to zero.
• Refresh: Updates data for existing cells without affecting the layout (optimized for performance).
• Refill: Clears and refills items from the start; triggers a full layout recalculation.
• RefillFromEnd: Clears and refills items from the end; triggers a full layout recalculation.

The following settings are available in the Inspector:

• Total Count: The total number of cells. Use a negative number to represent infinity.
• Reverse Direction: Enable this for scrolling from down-to-top (vertical) or right-to-left (horizontal). You must adjust the Content's pivot and anchor accordingly.