import "SDImageCache.h"
import "SDWebImageManager.h"
#pragma mark --------------- 获取网络图片的大小 ----------------
/**
* 获取网络图片的大小
*
* @param imageURL 图片的key，NSURL,NSString类型读可以
*
* @return 网络图片的大小
*/
+ (CGSize)imageSizeWithURL:(id)imageURL
{
NSURL* URL = nil;
if([imageURL isKindOfClass:[NSURL class]]){
URL = imageURL;
}
if([imageURL isKindOfClass:[NSString class]]){
URL = [NSURL URLWithString:imageURL];
}
if(URL == nil)
return CGSizeZero;
NSString * absoluteString = URL.absoluteString;
#ifdef dispatch_main_sync_safe 如果未使用SDWebImage，则忽略；检查是否缓存过该图片（注释它）
if([[SDImageCache sharedImageCache] diskImageExistsWithKey:absoluteString])
{
UIImage* image = [[SDImageCache sharedImageCache] imageFromMemoryCacheForKey:absoluteString];
if(!image)
{
NSData* data = [[SDImageCache sharedImageCache] performSelector:@selector(diskImageDataBySearchingAllPathsForKey:) withObject:URL.absoluteString];
image = [UIImage imageWithData:data];
}
if(image)
{
return image.size;
}
}
#endif
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:URL];
NSString* pathExtendsion = [URL.pathExtension lowercaseString];
CGSize size = CGSizeZero;
if([pathExtendsion isEqualToString:@"png"]){
size = [self downloadPNGImageSizeWithRequest:request];
}
else if([pathExtendsion isEqual:@"gif"])
{
size = [self downloadGIFImageSizeWithRequest:request];
}
else{
size = [self downloadJPGImageSizeWithRequest:request];
}
if(CGSizeEqualToSize(CGSizeZero, size))
{
NSData* data = [NSURLConnection sendSynchronousRequest:[NSURLRequest requestWithURL:URL] returningResponse:nil error:nil];
UIImage* image = [UIImage imageWithData:data];
if(image)
{
#ifdef dispatch_main_sync_safe 如果未使用SDWebImage，则忽略；缓存该图片（注释它）
[[SDImageCache sharedImageCache] storeImage:image recalculateFromImage:YES imageData:data forKey:URL.absoluteString toDisk:YES];
#endif
size = image.size;
}
}
return size;
}
+ (CGSize)downloadPNGImageSizeWithRequest:(NSMutableURLRequest*)request
{
[request setValue:@"bytes=16-23" forHTTPHeaderField:@"Range"];
NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
if(data.length == 8)
{
int w1 = 0, w2 = 0, w3 = 0, w4 = 0;
[data getBytes:&w1 range:NSMakeRange(0, 1)];
[data getBytes:&w2 range:NSMakeRange(1, 1)];
[data getBytes:&w3 range:NSMakeRange(2, 1)];
[data getBytes:&w4 range:NSMakeRange(3, 1)];
int w = (w1 << 24) + (w2 << 16) + (w3 << 8) + w4;
int h1 = 0, h2 = 0, h3 = 0, h4 = 0;
[data getBytes:&h1 range:NSMakeRange(4, 1)];
[data getBytes:&h2 range:NSMakeRange(5, 1)];
[data getBytes:&h3 range:NSMakeRange(6, 1)];
[data getBytes:&h4 range:NSMakeRange(7, 1)];
int h = (h1 << 24) + (h2 << 16) + (h3 << 8) + h4;
return CGSizeMake(w, h);
}
return CGSizeZero;
}
+ (CGSize)downloadGIFImageSizeWithRequest:(NSMutableURLRequest*)request
{
[request setValue:@"bytes=6-9" forHTTPHeaderField:@"Range"];
NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
if(data.length == 4)
{
short w1 = 0, w2 = 0;
[data getBytes:&w1 range:NSMakeRange(0, 1)];
[data getBytes:&w2 range:NSMakeRange(1, 1)];
short w = w1 + (w2 << 8);
short h1 = 0, h2 = 0;
[data getBytes:&h1 range:NSMakeRange(2, 1)];
[data getBytes:&h2 range:NSMakeRange(3, 1)];
short h = h1 + (h2 << 8);
return CGSizeMake(w, h);
}
return CGSizeZero;
}
+ (CGSize)downloadJPGImageSizeWithRequest:(NSMutableURLRequest*)request
{
[request setValue:@"bytes=0-209" forHTTPHeaderField:@"Range"];
NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
if ([data length] <= 0x58) {
return CGSizeZero;
}
if ([data length] < 210) {// 肯定只有一个DQT字段
short w1 = 0, w2 = 0;
[data getBytes:&w1 range:NSMakeRange(0x60, 0x1)];
[data getBytes:&w2 range:NSMakeRange(0x61, 0x1)];
short w = (w1 << 8) + w2;
short h1 = 0, h2 = 0;
[data getBytes:&h1 range:NSMakeRange(0x5e, 0x1)];
[data getBytes:&h2 range:NSMakeRange(0x5f, 0x1)];
short h = (h1 << 8) + h2;
return CGSizeMake(w, h);
} else {
short word = 0x0;
[data getBytes:&word range:NSMakeRange(0x15, 0x1)];
if (word == 0xdb) {
[data getBytes:&word range:NSMakeRange(0x5a, 0x1)];
if (word == 0xdb) {// 两个DQT字段
short w1 = 0, w2 = 0;
[data getBytes:&w1 range:NSMakeRange(0xa5, 0x1)];
[data getBytes:&w2 range:NSMakeRange(0xa6, 0x1)];
short w = (w1 << 8) + w2;
short h1 = 0, h2 = 0;
[data getBytes:&h1 range:NSMakeRange(0xa3, 0x1)];
[data getBytes:&h2 range:NSMakeRange(0xa4, 0x1)];
short h = (h1 << 8) + h2;
return CGSizeMake(w, h);
} else {// 一个DQT字段
short w1 = 0, w2 = 0;
[data getBytes:&w1 range:NSMakeRange(0x60, 0x1)];
[data getBytes:&w2 range:NSMakeRange(0x61, 0x1)];
short w = (w1 << 8) + w2;
short h1 = 0, h2 = 0;
[data getBytes:&h1 range:NSMakeRange(0x5e, 0x1)];
[data getBytes:&h2 range:NSMakeRange(0x5f, 0x1)];
short h = (h1 << 8) + h2;
return CGSizeMake(w, h);
}
} else {
return CGSizeZero;
}
}
}
2.获取SDWebImage缓存图片的大小
/**
* 获取SDWebImage缓存图片的大小
*
* @param imageURL 图片的key，NSURL,NSString类型读可以
*
* @return 图片的大小，当为CGSizeZero，需要自己去获取
*/
+ (CGSize)getSDWebImageSizeWithURL:(id)imageURL
{
NSURL* URL = nil;
if([imageURL isKindOfClass:[NSURL class]]){
URL = imageURL;
}
if([imageURL isKindOfClass:[NSString class]]){
URL = [NSURL URLWithString:imageURL];
}
// NSURL *url = [NSURL URLWithString:string];
SDWebImageManager *manager = [SDWebImageManager sharedManager];
BOOL existBool = [manager diskImageExistsForURL:URL];//判断是否有缓存
UIImage *image = [[UIImage alloc] init];
CGSize size;
if (existBool)
{
image = [[manager imageCache] imageFromDiskCacheForKey:URL.absoluteString];
return size = image.size;
}
else
return CGSizeZero;
}
3.设置图片
[self.imageView sd_setImageWithURL:[NSURL URLWithString:@"http://www.domain.com/path/to/image.jpg"] placeholderImage:[UIImage imageNamed:@"placeholder.png"]];
4.下载缓存图片，能够得到图片的大小
/**
* 下载缓存图片，能够得到图片的大小
*
* @param imageURL 图片的key，NSURL,NSString类型读可以
* @param success 图片，图片的size为image.size
* @param failure 错误的提示
*/
+ (void)dowmloadImageWithURL:(id)imageURL success:(void(^)(UIImage *image))success failure:(void(^)(NSError *error))failure
{
NSURL* URL = nil;
if([imageURL isKindOfClass:[NSURL class]]){
URL = imageURL;
}
if([imageURL isKindOfClass:[NSString class]]){
URL = [NSURL URLWithString:imageURL];
}
SDWebImageManager *manager = [SDWebImageManager sharedManager];
//判断是否有缓存
BOOL existBool = [manager diskImageExistsForURL:URL];
if (existBool)//有缓存
{
UIImage *image = [[manager imageCache] imageFromDiskCacheForKey:URL.absoluteString];
success(image);
}
else//无缓存
{
//使用这个会缓存数据
[manager downloadImageWithURL:URL options:0 progress:^(NSInteger receivedSize, NSInteger expectedSize) {
} completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, BOOL finished, NSURL *imageURL) {
if (image) {
success(image);
} else {
failure(error);
}
}];
// //SDWebImageDownloader只会下载图片不会缓存
// SDWebImageDownloader *downer = [SDWebImageDownloader sharedDownloader];
// [downer downloadImageWithURL:URL options:0 progress:^(NSInteger receivedSize, NSInteger expectedSize) {
//
// } completed:^(UIImage *image, NSData *data, NSError *error, BOOL finished) {
//
// }];
}
}
5.清理
-(void)applicationDidReceiveMemoryWarning:(UIApplication *)application
{
//1.清空缓存
//clear:直接删除缓存目录下面的文件,然后重新创建空的缓存文件
//clean:清除过期缓存,计算当前缓存的大小,和设置的最大缓存数量比较,如果超出那么会继续删除(按照文件了创建的先后顺序)
//过期时间:7天
[[SDWebImageManager sharedManager].imageCache clearMemory];
//2.取消当前所有的操作
[[SDWebImageManager sharedManager] cancelAll];
//3.最大并发数量 == 6
//4.缓存文件的保存名称如何处理? 拿到图片的URL路径,对该路径进行MD5加密
//5.该框架内部对内存警告的处理方式? 内部通过监听通知的方式请你缓存
//6.该框架进行缓存处理的方式:可变字典--->NSCache
//7.如何判断图片的类型: 在判断图片类型的时候，只匹配第一个字节
//8.队列中任务的处理方式:FIFO
//9.如何下载图片的? 发送网络请求下载图片,NSURLConnection
//10.请求超时的时间 15秒
//清除缓存数据
//cleanDisk：删除过期的文件数据，计算当前未过期的已经下载的文件数据的大小，如果发现该数据大小大于我们设置的最大缓存数据大小，那么程序内部会按照按文件数据缓存的时间从远到近删除，知道小于最大缓存数据为止。
//clearMemory:直接删除文件，重新创建新的文件夹
//[[SDWebImageManager sharedManager].imageCache cleanDisk];
[[SDWebImageManager sharedManager].imageCache clearMemory];
04 SDWebImage默认的缓存时间是1周
}
一，options所有选项：
//失败后重试
SDWebImageRetryFailed = 1 << 0,
//UI交互期间开始下载，导致延迟下载比如UIScrollView减速。
SDWebImageLowPriority = 1 << 1,
//只进行内存缓存
SDWebImageCacheMemoryOnly = 1 << 2,
//这个标志可以渐进式下载,显示的图像是逐步在下载
SDWebImageProgressiveDownload = 1 << 3,
//刷新缓存
SDWebImageRefreshCached = 1 << 4,
//后台下载
SDWebImageContinueInBackground = 1 << 5,
//NSMutableURLRequest.HTTPShouldHandleCookies = YES;
SDWebImageHandleCookies = 1 << 6,
//允许使用无效的SSL证书
//SDWebImageAllowInvalidSSLCertificates = 1 << 7,
//优先下载
SDWebImageHighPriority = 1 << 8,
//延迟占位符
SDWebImageDelayPlaceholder = 1 << 9,
//改变动画形象
SDWebImageTransformAnimatedImage = 1 << 10,
