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注：#import "YGFileDownloader.h"是对NSURLConnection的简单封装

#import "YGResumeDownloadViewController.h"

#import "NSString+util.h" #import "YGFileDownloader.h" #define URL @"http://dlsw.baidu.com/sw-search-sp/soft/2a/25677/QQ_V4.0.0.1419920162.dmg" @interface YGResumeDownloadViewController () <YGFileDownloaderDelegate> @property (weak, nonatomic) IBOutlet UIProgressView *progressView; @end @implementation YGResumeDownloadViewController - (void)viewDidLoad {     [super viewDidLoad];     // Do any additional setup after loading the view from its nib.     NSUserDefaults *defaults=[NSUserDefaults standardUserDefaults];     float progress=[defaults floatForKey:@"self.progressView.progress"];     if (progress)     {         self.progressView.progress=[defaults floatForKey:@"self.progressView.progress"];     } } - (IBAction)download:(id)sender {     YGFileDownloader *downloader=[YGFileDownloader sharedInstance];     downloader.delegate=self;     [downloader start:URL]; } - (IBAction)pauseDownload:(id)sender {     [[YGFileDownloader sharedInstance] stop]; } #pragma mark - <YGFileDownloaderDelegate> -(void)fileDownloaderFailWithError:(NSError *)error{     NSLog(@"失败"); } -(void)fileDownloader:(YGFileDownloader *)downloader downloadSize:(unsigned long long)downloadSize totalSize:(unsigned long long)totalSize{     self.progressView.progress=1.0*downloadSize/totalSize;     float p=self.progressView.progress;     //NSLog(@"进度条:%f",p);     NSUserDefaults *dafaults=[NSUserDefaults standardUserDefaults];     [dafaults setFloat:p forKey:@"self.progressView.progress"]; } -(void)fileDownloaderDidFinishLoad{     NSLog(@"下载完了"); }

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