如何在从Document Directory iOS读写图像期间处理内存警告

Question

I am using below code for reading & writing code in document directory , my problem is that when there is large size images downloaded then application gives memory warning and crash immigiate so how to handle this.

- (void)cacheImage:(UIImage *)image forRequest:(NSURLRequest *)request
{
    NSData *data=UIImageJPEGRepresentation(image, 1.0);
    [self writeImageData:data forPlayListID:[self cachedFileNameForKey:request.URL.absoluteString]];
}


-(UIImage *)getImageFromForPlayListID:(NSString *)strID{

    NSString *docDirPath=[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    docDirPath = [docDirPath stringByAppendingPathComponent:@"/MyFolder"];

    NSString *filePathCellImg = [NSString stringWithFormat:@"%@/%@",docDirPath,strID];
    NSData *data=[NSData dataWithContentsOfFile:filePathCellImg];
    UIImage *musicImage = [UIImage imageWithData:data];
    return musicImage;
}


-(void)writeImageData:(NSData *)imageData forPlayListID:(NSString *)strID{

    NSError *error;
    NSString *docDirPath=[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

    NSString *dataPath = [docDirPath stringByAppendingPathComponent:@"/MyFolder"];


    if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
        [[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:&error];

    //  [[NSFileManager defaultManager] removeItemAtPath:dataPath error:&error];

    NSString *filePathCellImg = [NSString stringWithFormat:@"%@/%@",dataPath,strID];


    [imageData writeToFile:filePathCellImg atomically:NO];
    if (![[NSFileManager defaultManager] fileExistsAtPath:filePathCellImg]) {
    [[NSFileManager defaultManager] createFileAtPath:filePathCellImg
                                            contents:imageData
                                          attributes:nil];
    }

}

Answer 1

Use SDWebImage t is best library for image caching...you can Pick it from below url(Github) https://github.com/rs/SDWebImage()

Like... // Here we use the new provided setImageWithURL: method to load the web image [cell.imageView setImageWithURL:[NSURL URLWithString:@" http://www.domain.com/path/to/image.jpg "] placeholderImage:[UIImage imageNamed:@"placeholder.png"] completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType) {... completion code here ...}];