8.ios之view的封装

1.view的封装

2.使用xib封装一个自定义view的步骤

1> 新建一个继承UIView的自定义view,假设类名叫做(MJAppView)
2> 新建一个MJAppView.xib文件来描述MJAppView内部的结构
3> 修改UIView的类型为MJAppView真是类型
4> 将内部的子控件跟MJAppView进行属性连线
5> MJAppView提供一个模型属性
6> 重写模型属性的set方法,因为在set方法中可以拿到外界传递的模型数据
7> 把模型数据拆开,分别设置数据到对应的子控件中
8> 补充:提供一个创建MJAppView的类方法,将读取xib文件的代码屏蔽起来

3.Sample

#import <UIKit/UIKit.h>

@class MJApp;

@interface MJAppView : UIView

/**
 *  模型数据
 */
@property (nonatomic, strong) MJApp *app;

+ (instancetype)appView;

/**
 *  通过模型数据来创建一个view
 */
+ (instancetype)appViewWithApp:(MJApp *)app;

@end



#import "MJAppView.h"
#import "MJApp.h"

@interface MJAppView()
@property (weak, nonatomic) IBOutlet UIImageView *iconView;
@property (weak, nonatomic) IBOutlet UILabel *nameLabel;
@end

@implementation MJAppView

//+ (instancetype)appView
//{
//    NSBundle *bundle = [NSBundle mainBundle];
//    // 读取xib文件(会创建xib中的描述的所有对象,并且按顺序放到数组中返回)
//    NSArray *objs = [bundle loadNibNamed:@"MJAppView" owner:nil options:nil];
//    return [objs lastObject];
//}
//
//+ (instancetype)appViewWithApp:(MJApp *)app
//{
//    MJAppView *appView = [self appView];
//    appView.app = app;
//    return appView;
//}

+ (instancetype)appViewWithApp:(MJApp *)app
{
    NSBundle *bundle = [NSBundle mainBundle];
    // 读取xib文件(会创建xib中的描述的所有对象,并且按顺序放到数组中返回)
    NSArray *objs = [bundle loadNibNamed:@"MJAppView" owner:nil options:nil];
    MJAppView *appView = [objs lastObject];
    appView.app = app;
    return appView;
}

+ (instancetype)appView
{
    return [self appViewWithApp:nil];
}

- (void)setApp:(MJApp *)app
{
    _app = app;
    
    // 1.设置图标
    self.iconView.image = [UIImage imageNamed:app.icon];
    
    // 2.设置名称
    self.nameLabel.text = app.name;
}

@end

#import "MJViewController.h"
#import "MJApp.h"
#import "MJAppView.h"

@interface MJViewController ()
/** 存放应用信息 */
@property (nonatomic, strong) NSArray *apps;
@end

@implementation MJViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    // 添加应用信息
    
    // 0.总列数(一行最多3列)
    int totalColumns = 3;
    
    // 1.应用的尺寸
    CGFloat appW = 85;
    CGFloat appH = 90;
    
    // 2.间隙 = (控制器view的宽度 - 3 * 应用宽度) / 4
    CGFloat marginX = (self.view.frame.size.width - totalColumns * appW) / (totalColumns + 1);
    CGFloat marginY = 15;
    
    // 3.根据应用个数创建对应的框框(index 0 ~ 11)
    for (int index = 0; index<self.apps.count; index++) {
        // 3.1.创建view
        MJAppView *appView = [MJAppView appViewWithApp:self.apps[index]];
        
        // 3.2.添加view
        [self.view addSubview:appView];
        
        // 3.3.设置frame
        int row = index / totalColumns;
        int col = index % totalColumns;
        // 计算x和y
        CGFloat appX = marginX + col * (appW + marginX);
        CGFloat appY = 30 + row * (appH + marginY);
        appView.frame = CGRectMake(appX, appY, appW, appH);
        
        // 3.4.设置数据
//        appView.app = self.apps[index];
    }
}

- (NSArray *)apps
{
    if (_apps == nil) {
        // 初始化
        
        // 1.获得plist的全路径
        NSString *path = [[NSBundle mainBundle] pathForResource:@"app.plist" ofType:nil];
        
        // 2.加载数组
        NSArray *dictArray = [NSArray arrayWithContentsOfFile:path];
        
        // 3.将dictArray里面的所有字典转成模型对象,放到新的数组中
        NSMutableArray *appArray = [NSMutableArray array];
        for (NSDictionary *dict in dictArray) {
            // 3.1.创建模型对象
            MJApp *app = [MJApp appWithDict:dict];
            
            // 3.2.添加模型对象到数组中
            [appArray addObject:app];
        }
        
        // 4.赋值
        _apps = appArray;
    }
    return _apps;
}

@end