iOS NSURLSessionDownloadTask设置代理文件下载的示例

#import "ViewController.h"@interface ViewController ()<NSURLSessionDownloadDelegate>@end@implementation ViewController-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{  [self delegate];}-(void)delegate{  //1.url  NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/resources/images/minion_03.png"];    //2.创建请求对象  NSURLRequest *request = [NSURLRequest requestWithURL:url];    //3.创建session ：注意代理为NSURLSessionDownloadDelegate  NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];    //4.创建Task  NSURLSessionDownloadTask *downloadTask = [session downloadTaskWithRequest:request];    //5.执行Task  [downloadTask resume];}#pragma mark ----------------------#pragma mark NSURLSessionDownloadDelegate/** * 写数据 * * @param session          会话对象 * @param downloadTask       下载任务 * @param bytesWritten       本次写入的数据大小 * @param totalBytesWritten     下载的数据总大小 * @param totalBytesExpectedToWrite 文件的总大小 */-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite{  //1. 获得文件的下载进度  NSLog(@"%f",1.0 * totalBytesWritten/totalBytesExpectedToWrite);}/** * 当恢复下载的时候调用该方法 * * @param fileOffset     从什么地方下载 * @param expectedTotalBytes 文件的总大小 */-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes{  NSLog(@"%s",__func__);}/** * 当下载完成的时候调用 * * @param location   文件的临时存储路径 */-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location{  NSLog(@"%@",location);    //1 拼接文件全路径  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);}/** * 请求结束 */-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error{  NSLog(@"didCompleteWithError");}@end