# UITableView & UICollectionView (iOS)

> UITableView, UICollectionView, data sources, delegates, cell reuse, custom cells

- 25 interview questions
- Mid-Level
- [Interview Questions: iOS](https://sharpskill.dev/en/technologies/ios/interview-questions.md)

## 1. What is the main purpose of the dequeueReusableCell method in UITableView?

**Answer**

The dequeueReusableCell method retrieves a reusable cell from the recycling pool. This optimizes memory by reusing off-screen cells rather than creating new instances constantly. This is critical for maintaining smooth performance during scrolling.

## 2. Which UITableViewDataSource method returns the number of rows in a given section?

**Answer**

The tableView(_:numberOfRowsInSection:) method from UITableViewDataSource returns the row count for each section. It's called by UITableView to calculate total height and manage cell recycling. This method is mandatory to implement.

## 3. What is the main advantage of using UICollectionViewFlowLayout over a custom layout?

**Answer**

UICollectionViewFlowLayout provides a prebuilt optimized grid layout that automatically handles spacing, alignment, and cell wrapping. It avoids implementing complex layout logic and is highly configurable through properties like minimumLineSpacing, itemSize, and sectionInset.

## 22 more questions available

- How to combine numberOfSections and numberOfRowsInSection methods for a multi-section structure?
- Which protocol provides methods for handling selection events in a UICollectionView?

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