iOS开发 利用关联对象(RunTime)为控件命名

前言

最近公司项目有类游戏答题的要求, 选对的题目, 答案和动画不一样, 但是界面是用for循环做的, 这样就得提取相应答案按钮对应的其他控件来换图片或者换动画, 一共十几个题型, 用tag记录实在是太蛋疼就直接用关联对象给控件命名了, 记起来也方便.

关联对象介绍

实现

这样给系统控件添加方法, 一般就是用分类, 所以用分类来实现类似view.tag的功能.

新建一个UIView+YNViewName的类目

声明文件:

#import <UIKit/UIKit.h>

@interface UIView (YNViewName)

- (UIView *)yn_viewNamed:(NSString *)name;

@property (copy, nonatomic) NSString *yn_viewName;

@end

实现文件:

记得先引用#import <objc/runtime.h>, 关联对象也是在runtime基础上做文章.

#import "UIView+YNViewName.h"
#import <objc/runtime.h>

static const void *YNViewNameKey = @"YNViewName";

@implementation UIView (YNViewName)

- (void)setYn_viewName:(NSString *)yn_viewName {
    objc_setAssociatedObject(self, YNViewNameKey, yn_viewName, OBJC_ASSOCIATION_COPY_NONATOMIC);;
}

- (NSString *)yn_viewName {
    return objc_getAssociatedObject(self, YNViewNameKey);
}

- (UIView *)yn_viewNamed:(NSString *)name {
    
    if (!name) {
        return nil;
    }
    
    return [self viewWithName:name];
}

- (UIView *)viewWithName:(NSString *)aName {
    
    if (!aName) {
        return nil;
    }
    
    if ([self.yn_viewName isEqualToString:aName]) {
        return self;
    }
    
    // 子视图递归
    for (UIView *subview in self.subviews) {
        UIView *theView = [subview yn_viewNamed:aName];
        if (theView) {
            return theView;
            break;
        }
    }
    
    return nil;
}

@end

用法

SB或者XIB

使用SB或者XIB, 可以不声明对象, 这种做法好与不好不做讨论. 详见demo.

代码

- (void)viewDidLoad {
    [super viewDidLoad];
    
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 400, 50, 25)];
    imageView.backgroundColor = [UIColor blackColor];
    imageView.yn_viewName = imageViewName;
    [self.view addSubview:imageView];
    
    UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];
    button.frame = CGRectMake(100, 450, 50, 25);
    button.backgroundColor = [UIColor greenColor];
    [button addTarget:self action:@selector(changeColor) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
}

- (void)changeColor {
    UIImageView *imageView = (UIImageView *)[self.view yn_viewNamed:imageViewName];
    imageView.backgroundColor = [UIColor grayColor];
}

Demo