#import "ViewController.h"@interface ViewController ()<NSURLSessionDownloadDelegate>@property (nonatomic, strong) NSURLSessionDownloadTask *downloadTask;@property (nonatomic, strong) NSData *resumData;@property (nonatomic, strong) NSURLSession *session;@end@implementation ViewController// 開始下載- (IBAction)startBtnClick:(id)sender{  //1.url  NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/resources/videos/minion_01.mp4"];    //2.創(chuàng)建請(qǐng)求對(duì)象  NSURLRequest *request = [NSURLRequest requestWithURL:url];    //3.創(chuàng)建session  NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];  self.session = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:[NSOperationQueue mainQueue]];    //4.創(chuàng)建Task  NSURLSessionDownloadTask *downloadTask = [self.session downloadTaskWithRequest:request];    //5.執(zhí)行Task  [downloadTask resume];    self.downloadTask = downloadTask;}//暫停是可以恢復(fù)- (IBAction)suspendBtnClick:(id)sender{  NSLog(@"+++++++++++++++++++暫停");  [self.downloadTask suspend];}//cancel:取消是不能恢復(fù)//cancelByProducingResumeData:是可以恢復(fù)- (IBAction)cancelBtnClick:(id)sender{  NSLog(@"+++++++++++++++++++取消");  //[self.downloadTask cancel];    //恢復(fù)下載的數(shù)據(jù)!=文件數(shù)據(jù)，也就是記錄開始下載的位置的相關(guān)信息，倘若是已下載的文件數(shù)據(jù)，就會(huì)存在內(nèi)存增大的問題  [self.downloadTask cancelByProducingResumeData:^(NSData * _Nullable resumeData) {    self.resumData = resumeData;  }];}- (IBAction)goOnBtnClick:(id)sender{  NSLog(@"+++++++++++++++++++恢復(fù)下載");  if(self.resumData)  {    self.downloadTask = [self.session downloadTaskWithResumeData:self.resumData];  }    [self.downloadTask resume];}#pragma mark ----------------------#pragma mark NSURLSessionDownloadDelegate/** * 寫數(shù)據(jù) * * @param session          會(huì)話對(duì)象 * @param downloadTask       下載任務(wù) * @param bytesWritten       本次寫入的數(shù)據(jù)大小 * @param totalBytesWritten     下載的數(shù)據(jù)總大小 * @param totalBytesExpectedToWrite 文件的總大小 */-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite{  //1. 獲得文件的下載進(jìn)度  NSLog(@"%f",1.0 * totalBytesWritten/totalBytesExpectedToWrite);}/** * 當(dāng)恢復(fù)下載的時(shí)候調(diào)用該方法 * * @param fileOffset     從什么地方下載 * @param expectedTotalBytes 文件的總大小 */-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes{  NSLog(@"%s",__func__);}/** * 當(dāng)下載完成的時(shí)候調(diào)用 * * @param location   文件的臨時(shí)存儲(chǔ)路徑 */-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location{  NSLog(@"%@",location);    //1 拼接文件全路徑  NSString *fullPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:downloadTask.response.suggestedFilename];    //2 剪切文件  [[NSFileManager defaultManager]moveItemAtURL:location toURL:[NSURL fileURLWithPath:fullPath] error:nil];  NSLog(@"%@",fullPath);}/** * 請(qǐng)求結(jié)束 */-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error{  NSLog(@"didCompleteWithError");}@end