TumblrDownloader/TumblrDownloader/ImageHandler.m

//
//  ImageHandler.m
//  TumblrDownloader
//
//  Created by HonorLee on 16/1/21.
//  Copyright © 2016年 HonorLee. All rights reserved.
//

#import "ImageHandler.h"

@implementation ImageHandler
+(NSString *)getAndSaveThumbImageFromURLandSetToImageView:(NSString *)imagePath saveToName:(NSString *)fileName setToImage:(UIImageView *)imageView{
    UIImage *oldImg;
    UIImage *newImg;
    NSData *imgData;
    NSString *filePath = [NSHomeDirectory() stringByAppendingPathComponent:[NSString stringWithFormat:@"/Library/Caches/%@.jpg",fileName]];
    BOOL needSave = NO;
    BOOL onError = NO;
//    NSError *error;
    NSFileManager *fs = [NSFileManager defaultManager];
    dispatch_group_t disG = dispatch_group_create();
    
    dispatch_group_enter(disG);
    if([fs fileExistsAtPath:filePath]){
        NSLog(@"Read File from cache");
        imgData = [NSData dataWithContentsOfFile:filePath];
    }else if([imagePath containsString:@"http"]){
        NSLog(@"Read File from URL stream");
        needSave = YES;
        imgData = [NSData dataWithContentsOfURL:[NSURL URLWithString:imagePath]];
    }else{
        onError = YES;
    }

    if(imgData){
        if(needSave){
            oldImg = [UIImage imageWithData:imgData];
            UIGraphicsBeginImageContext(CGSizeMake(60, 60));
            [oldImg drawInRect:CGRectMake(0, 0, 60, 60)];
            newImg = UIGraphicsGetImageFromCurrentImageContext();
            UIGraphicsEndImageContext();
        }else{
//            NSLog(@"%@",imgData);
            newImg = [UIImage imageWithData:imgData];
        }
    }else{
        onError = YES;
    }
    dispatch_group_leave(disG);
    
    
    dispatch_group_notify(disG, dispatch_get_main_queue(), ^{
        NSDictionary *obj = [NSDictionary dictionaryWithObjectsAndKeys:imageView,@"imageView",newImg,@"image", nil];
//        if(!onError) [imageView setImage:newImg];
        [NSThread detachNewThreadSelector:@selector(showImage:) toTarget:self withObject:obj];
        if(needSave){
            NSLog(@"Save file to cache");
            NSError *err;
            [UIImageJPEGRepresentation(newImg, 1.0) writeToFile:filePath options:NSDataWritingAtomic error:&err];
            NSLog(@"%@",err);
        }
    });
    return filePath;
}
+(void)showImage:(NSDictionary *)obj{
    UIImageView *imageView = [obj objectForKey:@"imageView"];
    UIImage *image = [obj objectForKey:@"image"];
    [imageView setImage:image];
}
@end