Custom Cell and UITableViewController Suggestion: A MVC Implementation
As a developer working with UIKit, you’ve likely encountered the need to create custom table view cells that require additional setup or rendering. One common scenario involves adding a UIView to a cell when a user swipes on it. In this article, we’ll explore how to implement a Model-View-Controller (MVC) architecture for your custom cell, addressing the challenge of adjusting the cell’s height based on the presence of the additional view.
Understanding MVC Architecture
In an MVC application, you separate concerns into three interconnected components:
- Model: Represents the data and business logic of your application.
- View: Handles user interface and visual presentation.
- Controller: Acts as an intermediary between the model and view, handling user input and updating the model accordingly.
By using MVC principles in your custom cell implementation, you’ll create a more maintainable, scalable, and testable codebase.
Custom Cell Implementation
Let’s assume you have a CustomCell class with a UIView property called optionsView. You’ve already implemented a swipe gesture recognizer on the cell to add or remove the optionsView.
// CustomCell.h
#import <UIKit/UIKit.h>
@interface CustomCell : UITableViewCell
@property (nonatomic, strong) UIView *optionsView;
@end
// CustomCell.m
#import "CustomCell.h"
@implementation CustomCell
- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
// Initialize cell components and add swipe gesture recognizer here
}
return self;
}
@end
Table View Data Source
To adjust the cell height based on the presence of optionsView, you need to modify the tableView:cellForRowAtIndexPath: method in your table view data source.
// tableViewDataSource.m
#import "TableViewDataSource.h"
#import "CustomCell.h"
@interface TableViewDataSource : NSObject <UITableViewDataSource>
@property (nonatomic, strong) NSArray<id> *data;
@end
@implementation TableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return self.data.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
CustomCell *cell = [tableView dequeueReusableCellWithIdentifier:@"CustomCell"];
if (!cell) {
cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"CustomCell"];
}
// Set up cell components here
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
CustomCell *cell = [self tableView:tableView cellForRowAtIndexPath:indexPath];
return cell.optionsView.frame.size.height + cell.frame.size.height; // Return adjusted height
}
@end
In the heightForRowAtIndexPath: method, we retrieve the optionsView frame and add its height to the cell’s frame size to calculate the new row height.
// tableViewDataSource.h
#import <UIKit/UIKit.h>
@interface TableViewDataSource : NSObject <UITableViewDataSource>
@property (nonatomic, strong) NSArray<id> *data;
@end
// CustomCell.m
#import "CustomCell.h"
@implementation CustomCell
- (void)setOptionsView:(UIView *)optionsView {
self.optionsView = optionsView;
// Update cell height here
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return [super tableView:tableView heightForRowAtIndexPath:indexPath] + self.optionsView.frame.size.height;
}
@end
In the CustomCell implementation, we added a new method called setOptionsView: to update the cell’s height based on the presence of optionsView.
// CustomCell.h
#import <UIKit/UIKit.h>
@interface CustomCell : UITableViewCell
@property (nonatomic, strong) UIView *optionsView;
- (void)setOptionsView:(UIView *)optionsView;
@end
Now that we’ve implemented the MVC architecture for our custom cell, let’s explore how to use it effectively in a real-world scenario.
Example Use Case
Suppose you have an array of objects with different properties. Each object corresponds to a row in your table view:
// Data Model
@interface RowObject : NSObject
@property (nonatomic, strong) NSString *title;
@property (nonatomic, strong) NSArray<UIView *> *options;
@end
You can create an instance of RowObject and add it to your table view data source array:
// tableViewDataSource.m
#import "TableViewDataSource.h"
#import "CustomCell.h"
@interface TableViewDataSource : NSObject <UITableViewDataSource>
@property (nonatomic, strong) NSArray<id> *data;
@end
@implementation TableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return self.data.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
RowObject *row = self.data[indexPath.row];
CustomCell *cell = [tableView dequeueReusableCellWithIdentifier:@"CustomCell"];
if (!cell) {
cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"CustomCell"];
}
// Set up cell components with row data here
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
RowObject *row = self.data[indexPath.row];
CustomCell *cell = [self tableView:tableView cellForRowAtIndexPath:indexPath];
cell.setOptionsView(row.options);
// Return adjusted height
return cell.optionsView.frame.size.height + cell.frame.size.height;
}
@end
In the heightForRowAtIndexPath: method, we retrieve the corresponding row object from the data array and pass its options to the custom cell using the setOptionsView: method.
By using MVC principles in your custom cell implementation, you can create a more maintainable, scalable, and testable codebase that effectively handles complex user interactions. Remember to separate concerns between the model, view, and controller to achieve a clean and efficient architecture for your application.
Last modified on 2025-01-04