IOS large file breakpoint download, iOS file breakpoint download

IOS large file breakpoint download, iOS file breakpoint download

When iOS downloads large files, the download may be interrupted due to network or human reasons. How can I perform resumable download?

// ResumeData file path # define XMGResumeDataFile [[NSSearchPathForDirectoriesInDomains (NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent: @ "resumeData. tmp "] # import" ViewController. h "@ interface ViewController () <NSURLSessionDownloadDelegate>/** download task */@ property (nonatomic, strong) NSURLSessionDownloadTask * task; /** save the last download information */@ property (nonatomic, strong) NSData * resumeData;/* session */@ property (nonatomic, strong) NSURLSession * session; @ end

 

 

@ Implementation ViewController/** session */-(NSURLSession *) session {if (! _ Session) {_ session = [NSURLSession sessionWithConfiguration: [NSURLSessionConfiguration defaultSessionConfiguration] delegate: self delegateQueue: [[NSOperationQueue alloc] init];} return _ session ;} /*** start download */-(IBAction) start :( id) sender {self. task = [self. session downloadTaskWithURL: [NSURL URLWithString: @ "http: // 120.25.226.186: 32812/resources/videos/minion_01.mp4"]; [self. task resume];}/*** pause download */-(IBAction) pause :( id) sender {// once this task is canceled, [self. task cancelByProducingResumeData: ^ (NSData * resumeData) {self. resumeData = resumeData;}];}/*** continue to download */-(IBAction) goOn :( id) sender {self. task = [self. session downloadTaskWithResumeData: self. resumeData]; [self. task resume] ;}# pragma mark-<NSURLSessionDownloadDelegate>-(void) URLSession :( NSURLSession *) session task :( NSURLSessionTask *) task didCompleteWithError :( NSError *) error {NSLog (@ "didCompleteWithError"); // save and restore Data self. resumeData = error. userInfo [callback];}-(void) URLSession :( NSURLSession *) session downloadTask :( NSURLSessionDownloadTask *) downloadTask didResumeAtOffset :( int64_t) fileOffset expectedTotalBytes :( int64_t) expectedTotalBytes {NSLog (@ "didResumeAtOffset");}/*** this method is called once every time data is written to a temporary file. * totalBytesExpectedToWrite: total size * totalBytesWritten: size of data written * bytesWritten: the number of data written this time */-(void) URLSession :( NSURLSession *) session downloadTask :( bytes *) downloadTask didWriteData :( int64_t) bytesWritten bytes :( int64_t) totalBytesWritten totalBytesExpectedToWrite :( int64_t) totalBytesExpectedToWrite {NSLog (@ "-------- % f", 1.0 * totalBytesWritten/totalBytesExpectedToWrite );} /*** this method will be called once the download is complete */-(void) URLSession :( NSURLSession *) session downloadTask :( NSURLSessionDownloadTask *) downloadTask didFinishDownloadingToURL :( NSURL *) location {// The actual path of the file to be stored in the future NSString * file = [[NSSearchPathForDirectoriesInDomains (NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent: downloadTask. response. suggestedFilename]; // cut the temporary file of location to the actual path NSFileManager * mgr = [NSFileManager defaultManager]; [mgr moveItemAtURL: location toURL: [NSURL fileURLWithPath: file] error: nil];} @ end