QLPreviewControllerDataSource (moe.platform.ios API)

```
public interface QLPreviewControllerDataSource
```
The QLPreviewControllerDataSource protocol declares the methods that the Preview Controller uses to access the contents of its data source object.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`long`	`numberOfPreviewItemsInPreviewController(QLPreviewController controller)`	Returns the number of items that the preview controller should preview.
`QLPreviewItem`	`previewControllerPreviewItemAtIndex(QLPreviewController controller, long index)`	Returns the item that the preview controller should preview.

- Method Detail
  - numberOfPreviewItemsInPreviewController
```
long numberOfPreviewItemsInPreviewController(QLPreviewController controller)
```
    Returns the number of items that the preview controller should preview.
    
    Parameters:
    
    controller - The Preview Controller.
    
    Returns:
    
    The number of items.
  - previewControllerPreviewItemAtIndex
```
QLPreviewItem previewControllerPreviewItemAtIndex(QLPreviewController controller,
                                                  long index)
```
    Returns the item that the preview controller should preview.
    
    Parameters:
    
    controller - The Preview Controller.
    
    index - The index of the item to preview.
    
    Returns:
    
    An item conforming to the QLPreviewItem protocol.