Assets.xcassets图片是拖到右边里面去的。

 

////  ViewController.m//  03-综合练习//#import "ViewController.h"@interface ViewController ()// 购物车@property (weak, nonatomic) IBOutlet UIView *shopCarView;// 添加按钮@property (weak, nonatomic) IBOutlet UIButton *addButton;// 删除按钮@property (weak, nonatomic) IBOutlet UIButton *removeButton;// 全局的下标//@property (nonatomic, assign) NSInteger index;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    // 给下标赋值//    self.index = 0;    //    // 裁剪多余部分(不可取)//    self.shopCarView.clipsToBounds = YES;}/** *  添加到购物车 * *  @param button 按钮 */- (IBAction)add:(UIButton *)button {/***********************1.定义一些常量*****************************/    // 1.总列数    NSInteger allCols = 3;    // 2.商品的宽度 和 高度    CGFloat width = 80;    CGFloat height = 100;    // 3.求出水平间距 和 垂直间距    CGFloat hMargin = (self.shopCarView.frame.size.width - allCols * width) / (allCols -1);    CGFloat vMargin = (self.shopCarView.frame.size.height - 2 * height) / 1;    // 4. 设置索引    NSInteger index = self.shopCarView.subviews.count;    // 5.求出x值    CGFloat x = (hMargin + width) * (index % allCols);    CGFloat y = (vMargin + height) * (index / allCols);    /***********************2.创建一个商品*****************************/  // 1.创建商品的view    UIView *shopView = [[UIView alloc] init];  // 2.设置frame    shopView.frame = CGRectMake(x, y, width, height);  // 3.设置背景颜色    shopView.backgroundColor = [UIColor greenColor];  // 4.添加到购物车    [self.shopCarView addSubview:shopView];    /***********************3.设置按钮的状态*****************************///    if (index == 5) {//        button.enabled = NO;//    }    button.enabled = (index != 5);        // 5.设置删除按钮的状态    self.removeButton.enabled = YES;        // 让下标+1//    self.index += 1;}/** *  从购物车中删除 * *  @param button 按钮 */- (IBAction)remove:(UIButton *)button {    // 1. 删除最后一个商品    UIView *lastShopView = [self.shopCarView.subviews lastObject];    [lastShopView removeFromSuperview];        // 2.设置索引值 -1//    self.index -= 1;        // 3. 设置添加按钮的状态    self.addButton.enabled = YES;        // 4. 设置删除按钮的状态    /*    if (self.shopCarView.subviews.count == 0) {        self.removeButton.enabled = NO;    }     */    self.removeButton.enabled = (self.shopCarView.subviews.count != 0);    }@end