整理一個簡單的購物車小demo。主要利用“通知”來實現(xiàn)事件的傳遞。通知的發(fā)布和監(jiān)聽、移除通知。(資料來源于小碼哥)

• UITableView 搭建基本骨架、加減按鈕的圓角邊框處理、底部工具條及數(shù)據(jù)顯示
• model
• UITableViewCell 自定義
• NSNotificationCenter 監(jiān)聽發(fā)布及移除

效果圖.png

如上圖所示：點擊加減按鈕可以改變購物數(shù)量，底部工具條上的總價也隨之變化計算出相應(yīng)的價格總和。減號按鈕、清空購物車按鈕 默認(rèn)不能點擊，當(dāng)數(shù)量大于0時可以點擊。

model.m文件

#import <Foundation/Foundation.h>

@interface MRootModle : NSObject
@property (copy, nonatomic) NSString *money;
@property (copy, nonatomic) NSString *name;
@property (copy, nonatomic) NSString *image;
//
@property (nonatomic,assign)int count;
@end

RootViewController.m文件

#import "RootViewController.h"
#import "RootTableViewCell.h"
#import "MRootModle.h"
#import "MJExtension.h"
#define ScreenWidth  [UIScreen mainScreen].bounds.size.width
#define ScreenHeight  [UIScreen mainScreen].bounds.size.height

@interface RootViewController ()<UITableViewDelegate,UITableViewDataSource>
@property (nonatomic,strong)UITableView *tableView;
@property (nonatomic,strong)NSArray *dataArray;//數(shù)據(jù)源
@property (nonatomic,strong)UILabel *priceLabel;//總價價格
@property (nonatomic,strong)UILabel *zongjiaLabel;//總價
@property (nonatomic,strong)UIButton *clearBtn;//清空購物車
@property (nonatomic,strong)UIButton *buyBtn;//購物
@end

@implementation RootViewController
//數(shù)據(jù)源
- (NSArray *)dataArray{
    if (!_dataArray) {
        _dataArray = [MRootModle  mj_objectArrayWithFilename:@"wine.plist"];
    }
       return _dataArray;
}
- (UITableView *)tableView{
    if (!_tableView) {
        _tableView = [[UITableView alloc]initWithFrame:CGRectMake(0, 0,ScreenWidth, ScreenHeight-49) style:UITableViewStylePlain];
        _tableView.delegate = self;
        _tableView.dataSource = self;
        _tableView.tableFooterView = [[UIView alloc]init];
    }
    return _tableView;
}
- (void)viewDidLoad {
    [super viewDidLoad];
    self.navigationItem.title = @"購物車";
    [self.view addSubview:self.tableView];
    [self creatFootView];
    //監(jiān)聽通知
    NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
    [center addObserver:self selector:@selector(plusClick:) name:@"plusClickNSNotification" object:nil];
    [center addObserver:self selector:@selector(minusClick:) name:@"minusClickNSNotification" object:nil];
}
- (void)creatFootView{
    //底部View
    UIView *footView = [[UIView alloc]initWithFrame:CGRectMake(0, ScreenHeight-49, ScreenWidth, 49)];
    footView.backgroundColor = [UIColor whiteColor];
    [self.view addSubview:footView];
    //黑線
    UIView *line = [[UIView alloc]initWithFrame:CGRectMake(0, ScreenHeight-49, ScreenWidth, 1)];
    line.backgroundColor = [UIColor blackColor];
    line.alpha = 0.3;
    [self.view addSubview:line];
    //總價
    _zongjiaLabel = [[UILabel alloc]initWithFrame:CGRectMake(15, 8, 60, 33)];
    _zongjiaLabel.font = [UIFont systemFontOfSize:15];
    _zongjiaLabel.text =@"總價:￥";
    [footView addSubview:_zongjiaLabel];
    //
    _priceLabel = [[UILabel alloc]initWithFrame:CGRectMake(65, 8, 100, 33)];
    _priceLabel.text = @"0";
    _priceLabel.textColor = [UIColor redColor];
    [footView addSubview:_priceLabel];
    //購物
    _buyBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    _buyBtn.frame = CGRectMake(ScreenWidth - 160, 8, 40, 33);
    [_buyBtn setTitle:@"購物" forState:UIControlStateNormal];
    [_buyBtn setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
    _buyBtn.font = [UIFont systemFontOfSize:17];
        [_buyBtn addTarget:self action:@selector(buyClick:) forControlEvents:UIControlEventTouchUpInside];
    [footView addSubview:_buyBtn];
    //清空購物車
    _clearBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    _clearBtn.frame = CGRectMake(ScreenWidth-160, 8, 200, 33);
    [_clearBtn setTitle:@"清空購物車" forState:UIControlStateNormal];
    [_clearBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    _clearBtn.font = [UIFont systemFontOfSize:17];
    [_clearBtn addTarget:self action:@selector(clearClick:) forControlEvents:UIControlEventTouchUpInside];
    [footView addSubview:_clearBtn];
}
//購買
- (void)buyClick:(UIButton *)btn{
    NSLog(@"購買");
}
//清空購物車
- (void)clearClick:(UIButton *)btn{
    //清除模型里的數(shù)據(jù)
    for (MRootModle *model in _dataArray) {
        model.count = 0;
    }
    //刷新表格數(shù)據(jù)
    [self.tableView reloadData];
    self.priceLabel.text = @"0";
    self.clearBtn.enabled = NO;
    NSLog(@"清空購物車");
}
//減號的通知事件
- (void)plusClick:(NSNotification *)notif{
    RootTableViewCell *cell =notif.object;
    int price =self.priceLabel.text.intValue+cell.model.money.intValue;
    //如果有文字就不行轉(zhuǎn)換
     _priceLabel.text = [NSString stringWithFormat:@"%d",price];
    if (price>0) {
        _clearBtn.enabled = YES;
        [_buyBtn setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
    }
}
//加號的通知事件
- (void)minusClick:(NSNotification *)notif{

    RootTableViewCell *cell = notif.object;
    int price = self.priceLabel.text.intValue - cell.model.money.intValue;
    _priceLabel.text =[NSString stringWithFormat:@"%d",price];
    if (price==0) {
        _clearBtn.enabled = NO;
        [_buyBtn setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
    }
}

- (void)dealloc{
    //移除通知
    [[NSNotificationCenter defaultCenter]removeObserver:self];
}

/**
 代理
 */

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    return self.dataArray.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    RootTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"iden"];
    if (cell == nil) {
        cell= [[RootTableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"iden"];
    }
    cell.model =_dataArray[indexPath.row];

    cell.selectionStyle = UITableViewCellSelectionStyleNone;
    return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    [tableView deselectRowAtIndexPath:indexPath animated:YES];
}

TableViewCell.m文件

@interface RootTableViewCell ()

@property (nonatomic,strong)UIButton *jiaBtn;
@property (nonatomic,strong)UIButton *jianBtn;
@property (nonatomic,strong)UILabel *numLabel;
@property (nonatomic,strong)UIImageView *headerImageView;
@property (nonatomic,strong)UILabel *titletLabel;
@property (nonatomic,strong)UILabel *danjiaLabel;

@end

@implementation RootTableViewCell

- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier{
    if ([super initWithStyle:style reuseIdentifier:reuseIdentifier]) {
        [self createUI];
    }
    return self;
}
- (void)createUI{
    //圖片
    _headerImageView = [[UIImageView alloc]initWithFrame:CGRectMake(10, 2, 40, 40)];
    _headerImageView.backgroundColor = [UIColor brownColor];
    [self.contentView addSubview:_headerImageView];
    //題目
    _titletLabel = [[UILabel alloc]initWithFrame:CGRectMake(53, 0, 200, 30)];
    _titletLabel.textColor = [UIColor orangeColor];
    _titletLabel.font = [UIFont systemFontOfSize:11];
    [self.contentView addSubview:_titletLabel];
    //單價
    _danjiaLabel = [[UILabel alloc]initWithFrame:CGRectMake(53, 25, 50, 20)];
    _danjiaLabel.textColor = [UIColor orangeColor];
    _danjiaLabel.font = [UIFont systemFontOfSize:11];
    [self.contentView addSubview:_danjiaLabel];
    //加號button
    _jiaBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    _jiaBtn.frame = CGRectMake(ScreenWidth-50, 5, 35, 35);
     [_jiaBtn setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
    [_jiaBtn setTitle:@"+" forState:UIControlStateNormal];
    [_jiaBtn addTarget:self action:@selector(jiaClick) forControlEvents:UIControlEventTouchUpInside];
    [self custombutton:_jiaBtn];
    //數(shù)量
    _numLabel =[[UILabel alloc]initWithFrame:CGRectMake(ScreenWidth - 80, 12, 20, 20)];
    _numLabel.font = [UIFont systemFontOfSize:11];
    [self.contentView addSubview:_numLabel];
    //減號button
    _jianBtn = [UIButton buttonWithType:UIButtonTypeSystem];
    [_jianBtn setTitle:@"-" forState:UIControlStateNormal];
    _jianBtn.frame =CGRectMake(ScreenWidth-140, 5, 35, 35);
    _jianBtn.enabled = NO;
    [_jianBtn addTarget:self action:@selector(jianClick) forControlEvents:UIControlEventTouchUpInside];
    [self custombutton:_jianBtn];

}
-(void)setModel:(MRootModle *)model{
    _model =model;
    NSLog(@"%@",model.image);
    _headerImageView.image =[UIImage imageNamed:model.image];
    _titletLabel.text = model.name;
    _danjiaLabel.text = [NSString stringWithFormat:@"￥%@",model.money];
    _numLabel.text =[NSString stringWithFormat:@"%d",model.count];
    //判斷減號能不能用
    _jianBtn.enabled = (_model.count>0);
}
// + 按鈕
- (void)jiaClick{
    NSLog(@"加一件");
    self.model.count++;
    _numLabel.text =[NSString stringWithFormat:@"%d",self.model.count];
    if (_model.count>0) {
        self.jianBtn.enabled = YES;
    }
    //發(fā)布通知
    [[NSNotificationCenter defaultCenter]postNotificationName:@"plusClickNSNotification" object:self];
}
//  — 按鈕
- (void)jianClick{

    self.model.count--;
    _numLabel.text =[NSString stringWithFormat:@"%d",self.model.count];
    if (!(self.model.count>0)) {
        _numLabel.text =[NSString stringWithFormat:@"0"];
        _jianBtn.enabled =NO;
    }
    //發(fā)布通知
     [[NSNotificationCenter defaultCenter]postNotificationName:@"minusClickNSNotification" object:self];
    NSLog(@"減一件");

}
//處理加減按鈕的圓角邊框
- (void)custombutton:(UIButton *)btn{

    btn.layer.cornerRadius = btn.frame.size.width*0.5;
    btn.layer.borderWidth = 1;
    btn.layer.borderColor = [UIColor orangeColor].CGColor;
    [btn setTitleColor:[UIColor grayColor] forState:UIControlStateHighlighted];
    btn.titleLabel.font = [UIFont systemFontOfSize:25];
    [self.contentView addSubview:btn];

}

當(dāng)然也可以用KVO來關(guān)聯(lián)view與model。取代通知下面貼出代碼：

- (NSArray *)wineArray
{
    if (!_wineArray) {
        _wineArray = [XMGWine mj_objectArrayWithFilename:@"wine.plist"];
        NSLog(@"數(shù)據(jù)源%@",_wineArray);
        for (XMGWine *wine in _wineArray) {

            [wine addObserver:self forKeyPath:@"count" options:NSKeyValueObservingOptionNew| NSKeyValueObservingOptionOld context:nil];
        }
    }
    return _wineArray;
}

- (void)viewDidLoad {
    [super viewDidLoad];
}

- (void)dealloc {
    for (XMGWine *wine in _wineArray) {
        [wine removeObserver:self forKeyPath:@"count"];
    }
}

#pragma mark - KVO
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(XMGWine *)wine change:(NSDictionary<NSString *,id> *)change context:(void *)context{
    // NSKeyValueChangeNewKey == @"new"
    int new = [change[NSKeyValueChangeNewKey] intValue];
    // NSKeyValueChangeOldKey == @"old"
    int old = [change[NSKeyValueChangeOldKey] intValue];
    if (new > old) { // 數(shù)量增加,點擊加號
        // 計算總價
        int totalPrice = self.totalPriceLabel.text.intValue + wine.money.intValue;
        // 設(shè)置總價
        self.totalPriceLabel.text = [NSString stringWithFormat:@"%d",totalPrice];
        // 購買按鈕一定能點擊
        self.buyButton.enabled = YES;
    } else { // 數(shù)量減少,點擊減號
        // 計算總價
        int totalPrice = self.totalPriceLabel.text.intValue - wine.money.intValue;
        // 設(shè)置總價
        self.totalPriceLabel.text = [NSString stringWithFormat:@"%d",totalPrice];
        // 控制購買按鈕是否能點擊
        self.buyButton.enabled = (totalPrice > 0);

    }
}