IOS网络第一天 - 02SDWebImage

**************SDWebImage加载图片

#import "HMAppsViewController.h"
#import "HMApp.h"
#import "UIImageView+WebCache.h"

@interface HMAppsViewController ()
/**
 *  所有的应用数据
 */
@property (nonatomic, strong) NSMutableArray *apps;
@end

@implementation HMAppsViewController

#pragma mark - 懒加载
- (NSMutableArray *)apps
{
    if (!_apps) {
        // 1.加载plist
        NSString *file = [[NSBundle mainBundle] pathForResource:@"apps" ofType:@"plist"];
        NSArray *dictArray = [NSArray arrayWithContentsOfFile:file];
        
        // 2.字典 --> 模型
        NSMutableArray *appArray = [NSMutableArray array];
        for (NSDictionary *dict in dictArray) {
            HMApp *app = [HMApp appWithDict:dict];
            [appArray addObject:app];
        }
        
        // 3.赋值
        self.apps = appArray;
//        _apps = appArray;
    }
    return _apps;
}

#pragma mark - 初始化方法
- (void)viewDidLoad
{
    [super viewDidLoad];
    
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    
}

#pragma mark - Table view data source
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return self.apps.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *ID = @"app";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:ID];
    }
    
    // 取出模型
    HMApp *app = self.apps[indexPath.row];
    
    // 设置基本信息
    cell.textLabel.text = app.name;
    cell.detailTextLabel.text = app.download;
    
    // 下载图片
    NSURL *url = [NSURL URLWithString:app.icon];
    UIImage *placeholder = [UIImage imageNamed:@"placeholder"];
//    [cell.imageView sd_setImageWithURL:url placeholderImage:placeholder];
    
//    [cell.imageView sd_setImageWithURL:url placeholderImage:placeholder completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
//        NSLog(@"----图片加载完毕---%@", image);
//    }];
    //SDWebImageRetryFailed 尝试重复下载
   //SDWebImageLowPriority  交互不下载
    SDWebImageOptions options = SDWebImageRetryFailed | SDWebImageLowPriority;
    [cell.imageView sd_setImageWithURL:url placeholderImage:placeholder options:options progress:^(NSInteger receivedSize, NSInteger expectedSize) { // 这个block可能会被调用多次
        NSLog(@"下载进度：%f", (double)receivedSize / expectedSize);
    } completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
        NSLog(@"----图片加载完毕---%@", image);
    }];
    return cell;
}
@end

***************HMAppDelegate.m

#import "SDWebImageManager.h"

/**
 *  当app接收到内存警告  
 */
- (void)applicationDidReceiveMemoryWarning:(UIApplication *)application
{
    SDWebImageManager *mgr = [SDWebImageManager sharedManager];
    
    // 1.取消正在下载的操作
    [mgr cancelAll];
    
    // 2.清除内存缓存
    [mgr.imageCache clearMemory];
}