今天要说的是一种代码优化的技巧，我们知道，编程一直讲求高聚合，低耦合。一般地，我们会将一个页面的UITableviewDelegate和UITableviewDataSource写在同一个controller里，如果你只有一个数据源，这样写是可以的。但假设下面这种情况，如图，一个页面有多个数据源，如果在同一个controller里写的话，一个controller同时要遵守UITableViewDelegate，UITableviewDataSource，UICollectionDelegate,UICollectionDataSource,然后将这些代理实现，那controller的压力是不是会变得很大呢？接下来就是减压的时刻了。

两个数据源.png

分离出数据.jpeg

controller中的代理实现.jpeg

XSMutiCatagoryTableviewDataSource.h

#import <UIKit/UIKit.h>

typedef void (^MutiCatagoryTableViewCellConfigureBlock)(id cell, id item);

@interface XSMutiCatagoryTableViewDataSource : NSObject <UITableViewDataSource>

@property (nonatomic, copy) NSArray *items;

- (id)initWithItems:(NSArray *)items cellIdentifier:(NSString *)cellIdentifier configureCellBlock:(MutiCatagoryTableViewCellConfigureBlock)configureCellBlock;

- (id)itemAtIndexPath:(NSIndexPath *)indexPath;

@end

XSMutiCatagoryTableviewDataSource.m

#import "XSMutiCatagoryTableViewDataSource.h"

@interface XSMutiCatagoryTableViewDataSource ()

@property (nonatomic, copy) NSString *cellIdentifier;
@property (nonatomic, copy) MutiCatagoryTableViewCellConfigureBlock configureCellBlock;
@end

@implementation XSMutiCatagoryTableViewDataSource

- (id)initWithItems:(NSArray *)items cellIdentifier:(NSString *)cellIdentifier configureCellBlock:(MutiCatagoryTableViewCellConfigureBlock)configureCellBlock {
    self = [super init];
    if (self) {
        self.items = items;
        self.cellIdentifier = cellIdentifier;
        self.configureCellBlock = configureCellBlock;
    }
    return self;
}

#pragma mark - public methods
- (id)itemAtIndexPath:(NSIndexPath *)indexPath {
    return self.items[(NSUInteger)indexPath.row];
}

#pragma mark - UITableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return [self.items count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:self.cellIdentifier forIndexPath:indexPath];
    
    id item = [self itemAtIndexPath:indexPath];
    self.configureCellBlock(cell, item);
    
    return cell;
}
@end

然后就是controller里的事情了

XSMutiCatagoryViewController.m

#import "XSMutiCatagoryTableViewDataSource.h"
@interface XSMutiCatagoryViewController () <UITableViewDelegate>
@property (strong, nonatomic) XSMutiCatagoryTableViewDataSource *mutiCatagoryTableViewDataSource;
@property (strong, nonatomic) UITableView *tableView;
@property (strong, nonatomic) MenuBridge *menuBridge;//数据源
@end
@implementation XSMutiCatagoryViewController

#pragma mark - life cycle
- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    CGFloat height = [UIScreen mainScreen].bounds.size.height;
    CGFloat width  = [UIScreen mainScreen].bounds.size.width;
    self.tableView.frame      = CGRectMake(0,64, width / 4, height-49-64);
}
- (void)viewDidLoad {
    [super viewDidLoad];
    [self.view addSubview:self.tableView];
    [self loadMenuData];
}
#pragma mark - http menthods
- (void)loadMenuData {
    __weak typeof(self) weakSelf = self;
    [MBProgressHUD showHUDAddedTo:self.view animated:YES];
    XSAPIManager *manager = [XSAPIManager manager];
    [manager GET:url parameters:parameters success:^(id responseObject) {
        //NSLog(@"分类页tableview数据%@",responseObject);
        weakSelf.menuBridge = [MenuBridge mj_objectWithKeyValues:responseObject];

        if (weakSelf.menuBridge.data.count > 0) {
            weakSelf.mutiCatagoryTableViewDataSource.items = weakSelf.menuBridge.data;
            [weakSelf.tableView reloadData];
            [weakSelf.tableView selectRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0] animated:YES scrollPosition:UITableViewScrollPositionBottom];
            [weakSelf tableView:weakSelf.tableView didSelectRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0]];
        }

        [MBProgressHUD hideAllHUDsForView:weakSelf.view animated:YES];
    } failure:^(NSError *error) {
        
        [MBProgressHUD hideAllHUDsForView:weakSelf.view animated:YES];
    }];
}
#pragma mark - getters and setters
- (UITableView *)tableView {
    if (_tableView == nil) {
        _tableView = [[UITableView alloc] init];
        _tableView.backgroundColor = MENU_COLOR;
        _tableView.separatorColor  = OTHER_SEPARATOR_COLOR;
        [_tableView registerNib:[UINib nibWithNibName:@"XSMutiCatagoryTableViewCell" bundle:nil] forCellReuseIdentifier:tableCellId];
        _tableView.delegate   = self;
        _tableView.dataSource = self.mutiCatagoryTableViewDataSource;
        _tableView.rowHeight = 49.0f;
    }
    return _tableView;
}

- (XSMutiCatagoryTableViewDataSource *)mutiCatagoryTableViewDataSource {
    if (_mutiCatagoryTableViewDataSource == nil) {
        _mutiCatagoryTableViewDataSource = [[XSMutiCatagoryTableViewDataSource alloc] initWithItems:self.menuBridge.data cellIdentifier:tableCellId configureCellBlock:^(XSMutiCatagoryTableViewCell *cell, Menu *item) {
            [cell configureForMenuItem:item];
        }];
    }
    return _mutiCatagoryTableViewDataSource;
}

以上。