前言
最近公司項目有類游戲答題的要求, 選對的題目, 答案和動畫不一樣, 但是界面是用for循環(huán)做的, 這樣就得提取相應答案按鈕對應的其他控件來換圖片或者換動畫, 一共十幾個題型, 用tag記錄實在是太蛋疼就直接用關(guān)聯(lián)對象給控件命名了, 記起來也方便.
關(guān)聯(lián)對象介紹
實現(xiàn)
這樣給系統(tǒng)控件添加方法, 一般就是用分類, 所以用分類來實現(xiàn)類似view.tag的功能.
新建一個UIView+YNViewName的類目
聲明文件:
#import <UIKit/UIKit.h>
@interface UIView (YNViewName)
- (UIView *)yn_viewNamed:(NSString *)name;
@property (copy, nonatomic) NSString *yn_viewName;
@end
實現(xiàn)文件:
記得先引用#import <objc/runtime.h>, 關(guān)聯(lián)對象也是在runtime基礎(chǔ)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;
}
// 子視圖遞歸
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, 可以不聲明對象, 這種做法好與不好不做討論. 詳見demo.
SB或者XIB
代碼
- (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];
}
