轻量级UIImageView分类缓存 库 AsyncImageView 使用

轻量级UIImageView分类缓存 库 AsyncImageView 使用

一：

• AsyncImageView 主页：https://github.com/nicklockwood/AsyncImageView
• 只包含了一个 .h 一个 .m文件
• 兼容 iOS 5.0及以上，以及ARC

二：使用

主要演示结合UITableview的使用

demo代码：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
        //create new cell
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];

        //common settings
        cell.selectionStyle = UITableViewCellSelectionStyleNone;
        cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;
        cell.imageView.contentMode = UIViewContentModeScaleAspectFill;
        cell.imageView.frame = CGRectMake(0.0f, 0.0f, 44.0f, 44.0f);
        cell.imageView.clipsToBounds = YES;
    }
    else
    {
        //cancel loading previous image for cell
        [[AsyncImageLoader sharedLoader] cancelLoadingImagesForTarget:cell.imageView];
    }

    //set placeholder image or cell won't update when image is loaded
    cell.imageView.image = [UIImage imageNamed:@"Placeholder.png"];

    //load the image
    cell.imageView.imageURL = self.imageURLs[(NSUInteger)indexPath.row];

    //display image path
    cell.textLabel.text = [[(NSURL *)self.imageURLs[(NSUInteger)indexPath.row] path] lastPathComponent];

    return cell;
}

demo 代码：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";

#define IMAGE_VIEW_TAG 99

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
        //create new cell
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];

        //add AsyncImageView to cell
        AsyncImageView *imageView = [[AsyncImageView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 44.0f, 44.0f)];
        imageView.contentMode = UIViewContentModeScaleAspectFill;
        imageView.clipsToBounds = YES;
        imageView.tag = IMAGE_VIEW_TAG;
        [cell addSubview:imageView];

        //common settings
        cell.selectionStyle = UITableViewCellSelectionStyleNone;
        cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;
        cell.indentationWidth = 44.0f;
        cell.indentationLevel = ;
    }

    //get image view
    AsyncImageView *imageView = (AsyncImageView *)[cell viewWithTag:IMAGE_VIEW_TAG];

    //cancel loading previous image for cell
    [[AsyncImageLoader sharedLoader] cancelLoadingImagesForTarget:imageView];

    //load the image
    imageView.imageURL = [_imageURLs objectAtIndex:indexPath.row];

    //display image path
    cell.textLabel.text = [[[_imageURLs objectAtIndex:indexPath.row] path] lastPathComponent];

    return cell;
}

三：可用api

@interface AsyncImageLoader : NSObject

+ (AsyncImageLoader *)sharedLoader;
+ (NSCache *)defaultCache;

@property (nonatomic, strong) NSCache *cache;
@property (nonatomic, assign) NSUInteger concurrentLoads;
@property (nonatomic, assign) NSTimeInterval loadingTimeout;

- (void)loadImageWithURL:(NSURL *)URL target:(id)target success:(SEL)success failure:(SEL)failure;
- (void)loadImageWithURL:(NSURL *)URL target:(id)target action:(SEL)action;
- (void)loadImageWithURL:(NSURL *)URL;
- (void)cancelLoadingURL:(NSURL *)URL target:(id)target action:(SEL)action;
- (void)cancelLoadingURL:(NSURL *)URL target:(id)target;
- (void)cancelLoadingURL:(NSURL *)URL;
- (void)cancelLoadingImagesForTarget:(id)target action:(SEL)action;
- (void)cancelLoadingImagesForTarget:(id)target;
- (NSURL *)URLForTarget:(id)target action:(SEL)action;
- (NSURL *)URLForTarget:(id)target;

@end

@interface UIImageView(AsyncImageView)

@property (nonatomic, strong) NSURL *imageURL;

@end

@interface AsyncImageView : UIImageView

@property (nonatomic, assign) BOOL showActivityIndicator;
@property (nonatomic, assign) UIActivityIndicatorViewStyle activityIndicatorStyle;
@property (nonatomic, assign) NSTimeInterval crossfadeDuration;

@end