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檢測(cè)SDWebImage有沒有緩存圖片 IOS 獲取網(wǎng)絡(luò)圖片大小

發(fā)布時(shí)間：2020-06-22 13:18:37 來源：網(wǎng)絡(luò) 閱讀：3785 作者：Im劉亞芳 欄目：移動(dòng)開發(fā) 
NSURL *url = [NSURL URLWithString:[model.content objectForKey:@"p_w_picpath"]];
            //請(qǐng)求網(wǎng)絡(luò)地址數(shù)據(jù)的同步方法
            //因?yàn)檫@個(gè)方法在子線程(全局隊(duì)列)中執(zhí)行,所以不需要考慮死線程的問題
            SDWebImageManager *manager = [SDWebImageManager sharedManager];
             [manager diskImageExistsForURL:url];
            if ([manager diskImageExistsForURL:url]) {
                LOG(@"11111")
                self.speakImage = [[manager p_w_picpathCache] p_w_picpathFromDiskCacheForKey:url.absoluteString];
            }else{
                LOG(@"3333333")
                NSData *data = [NSData dataWithContentsOfURL:url];
                self.speakImage = [UIImage p_w_picpathWithData:data];
            }



IOS 獲取網(wǎng)絡(luò)圖片大小

/**  
獲取網(wǎng)絡(luò)圖片的Size, 先通過文件頭來獲取圖片大小  
如果失敗 會(huì)下載完整的圖片Data 來計(jì)算大小 所以最好別放在主線程 
如果你有使用SDWebImage就會(huì)先看下 SDWebImage有緩存過改圖片沒有 
支持文件頭大小的格式 png、gif、jpg  http://www.cocoachina.com/bbs/read.php?tid=165823 
*/ 
+(CGSize)downloadImageSizeWithURL:(id)p_w_picpathURL;

//討厭警告
-(id)diskImageDataBySearchingAllPathsForKey:(id)key{return nil;}
+(CGSize)downloadImageSizeWithURL:(id)p_w_picpathURL
{
    NSURL* URL = nil;
    if([p_w_picpathURL isKindOfClass:[NSURL class]]){
        URL = p_w_picpathURL;
    }
    if([p_w_picpathURL isKindOfClass:[NSString class]]){
        URL = [NSURL URLWithString:p_w_picpathURL];
    }
    if(URL == nil)
        return CGSizeZero;
     
    NSString* absoluteString = URL.absoluteString;
     
#ifdef dispatch_main_sync_safe
    if([[SDImageCache sharedImageCache] diskImageExistsWithKey:absoluteString])
    {
        UIImage* p_w_picpath = [[SDImageCache sharedImageCache] p_w_picpathFromMemoryCacheForKey:absoluteString];
        if(!p_w_picpath)
        {
            NSData* data = [[SDImageCache sharedImageCache] performSelector:@selector(diskImageDataBySearchingAllPathsForKey:) withObject:URL.absoluteString];
            p_w_picpath = [UIImage p_w_picpathWithData:data];
        }
        if(!p_w_picpath)
        {
            return p_w_picpath.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* p_w_picpath = [UIImage p_w_picpathWithData:data];
        if(p_w_picpath)
        {
#ifdef dispatch_main_sync_safe
            [[SDImageCache sharedImageCache] storeImage:p_w_picpath recalculateFromImage:YES p_w_picpathData:data forKey:URL.absoluteString toDisk:YES];
#endif
            size = p_w_picpath.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 h2 = 0, h3 = 0, h4 = 0, h5 = 0;
        [data getBytes:&h2; range:NSMakeRange(4, 1)];
        [data getBytes:&h3; range:NSMakeRange(5, 1)];
        [data getBytes:&h4; range:NSMakeRange(6, 1)];
        [data getBytes:&h5; range:NSMakeRange(7, 1)];
        int h = (h2 << 24) + (h3 << 16) + (h4 << 8) + h5;
        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 h2 = 0, h3 = 0;
        [data getBytes:&h2; range:NSMakeRange(2, 1)];
        [data getBytes:&h3; range:NSMakeRange(3, 1)];
        short h = h2 + (h3 << 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) {// 肯定只有一個(gè)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 h2 = 0, h3 = 0;
        [data getBytes:&h2; range:NSMakeRange(0x5e, 0x1)];
        [data getBytes:&h3; range:NSMakeRange(0x5f, 0x1)];
        short h = (h2 << 8) + h3;
        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) {// 兩個(gè)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 h2 = 0, h3 = 0;
                [data getBytes:&h2; range:NSMakeRange(0xa3, 0x1)];
                [data getBytes:&h3; range:NSMakeRange(0xa4, 0x1)];
                short h = (h2 << 8) + h3;
                return CGSizeMake(w, h);
            } else {// 一個(gè)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 h2 = 0, h3 = 0;
                [data getBytes:&h2; range:NSMakeRange(0x5e, 0x1)];
                [data getBytes:&h3; range:NSMakeRange(0x5f, 0x1)];
                short h = (h2 << 8) + h3;
                return CGSizeMake(w, h);
            }
        } else {
            return CGSizeZero;
        }
    }
}


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