About me writing a custom cell

Why customize cell： The system provides cell It's not enough for complex styles , therefore ： Customize Cell Just like a custom view , Create one that meets our needs Cell And use this Cell.

• Unregistered

-(id)dequeueReusableCellWithIdentifier:(NSString *)identifier;

If there is no reuse cell, The program may return nil, So it's done cell After that, we must judge the air , If not, recreate . This method can be used without registration .

 // Try to get reusable cells . But not necessarily . No return nil
    UITableViewCell *cell = [_tableView dequeueReusableCellWithIdentifier:@"mycell"];
        
    if(cell == nil) {
    
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"mycell"];
    }

• register

(id)dequeueReusableCellWithIdentifier:(NSString *)identifier forIndexPath:(NSIndexPath *)indexPath;

Get the reused cell, If there is no reuse cell, Will automatically use the provided class Class to create a new cell And back to , There is no need to judge the space later . Before that, you must register cell.

[self.tableView registerClass:[MyTableViewCell class] forCellReuseIdentifier:@"mycell"];

MyTableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"mycell" forIndexPath:indexPath];

• difference

The difference in code is , The registered method needs to be reused in advance Cell Class registration , Instead of getting Cell Manually judge dequeue Is the result of nil, This is because dequeueReusableCellWithIdentifier:identifier forIndexPath: This process is handled internally , Make the last return must be available Cell.

Code customization cell：

Establish inheritance UITableViewCell Of MyTableViewCell file , Add the attributes we need for this class

// MyTableViewCell.h file 
@interface MyTableViewCell : UITableViewCell
@property UILabel *label;
@property UIButton *button;
@end

rewrite - (instancetype) initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier Method
& - (void) layoutSubviews Method

#import "MyTableViewCell.h"

@implementation MyTableViewCell

- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
    
    
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if ([self.reuseIdentifier isEqualToString:@"mycell"]) {
    
        _label = [[UILabel alloc] init];
        [self.contentView addSubview:_label];
        
        _button = [UIButton buttonWithType:UIButtonTypeCustom];
        [self.contentView addSubview:_btn];
        
    }
    return self;
}

// Layout 
- (void)layoutSubviews {
    
    _label.frame = CGRectMake(20, 20, 100, 50);
    _button.frame = CGRectMake(20, 80, 50, 50);
}


@end

.h Add an agreement to the document

@interface ViewController : UIViewController <UITableViewDelegate,UITableViewDataSource>

@property(nonatomic, strong) UITableView *tableView;

#import "ViewController.h"
#import "MyTableViewCell.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.view.backgroundColor = [UIColor whiteColor];
    self.tableView = [[UITableView alloc] initWithFrame:self.view.frame style:UITableViewStyleGrouped];
    [self.view addSubview:self.tableView];
    
    // Set proxy object 
    self.tableView.delegate = self;
    self.tableView.dataSource = self;
    
    [self.tableView registerClass:[MyTableViewCell class] forCellReuseIdentifier:@"mycell"];
  
 
}

// Group number 
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    
   return 2;
}
 
 // Number of rows in the group 
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    
    return 4;
}

// Cell height 
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    return 80;
}

// Set cell 
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    
    MyTableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"mycell" forIndexPath:indexPath];

    if(indexPath.section == 0) {
    
        cell.label.text = @"Leo";
        [cell.btn setImage:[UIImage imageNamed:@"1.jpg"] forState:UIControlStateNormal];
    } else {
    
        cell.label.text = @"Vincent";
        [cell.btn setImage:[UIImage imageNamed:@"2.jpg"] forState:UIControlStateNormal];
    }

    return cell;    
}

@end