iOS 开发之 为UIButton添加类别方法加载网络图片

使用GCD线程队列实现

UIButton+WebCache.h

#import <UIKit/UIKit.h>

// 为Button添加类别方法

@interface UIButton (WebCache)

- (void)xr_setButtonImageWithUrl:(NSString *)urlStr;

@end

UIButton+WebCache.m

#import "UIButton+WebCache.h"

@implementation UIButton (WebCache)

- (void)xr_setButtonImageWithUrl:(NSString *)urlStr {

NSURL * url = [NSURL URLWithString:urlStr];

// 根据图片的url下载图片数据

dispatch_queue_t xrQueue = dispatch_queue_create("loadImage", NULL); // 创建GCD线程队列

dispatch_async(xrQueue, ^{

// 异步下载图片

UIImage * img = [UIImage imageWithData:[NSData dataWithContentsOfURL:url]];

// 主线程刷新UI

dispatch_async(dispatch_get_main_queue(), ^{

[self setImage:img forState:UIControlStateNormal];

});

});

}

@end

使用：

[_ImgBtn xr_setButtonImageWithUrl:@"http://img3.3lian.com/2014/c2/66/d/56.jpg"];