supersr--NSURLSessionConfiguration-下载进度

//
//  ViewController.m
//  下载进度
//
//  Created by Super on 14/7/4.
//  Copyright (c) 2014年 iOS. All rights reserved.
//

#import "ViewController.h"

@interface ViewController () <NSURLSessionDownloadDelegate>
@property (nonatomic, strong) NSURLSession *session;

@property (nonatomic, strong) NSURLSessionDownloadTask *downloadTask;

@property (nonatomic, strong) NSData *data;
@property (weak, nonatomic) IBOutlet UIProgressView *processView;
@end
@implementation ViewController

- (NSURLSession *)session{
    if (_session == nil) {
        //代理方法运行的队列
        NSOperationQueue *queue =  [NSOperationQueue mainQueue];
//        //最大的并发线程数  ???????
        //在NSURLSession中使用NSOperationQueue设置最大并发数,无效
//        queue.maxConcurrentOperationCount = 1;
       
       
        NSURLSessionConfiguration *conf = [NSURLSessionConfiguration defaultSessionConfiguration];
        //创建自定义session  设置代理
        //session  会话
        _session = [NSURLSession sessionWithConfiguration:conf delegate:self delegateQueue:queue];
    }
    return _session;
}

//开始下载
- (IBAction)start:(id)sender {
    [self download];
}
//暂停pause 下载
- (IBAction)pause:(id)sender {
   
//    [self.downloadTask cancel];
   
    NSLog(@"zan ting");
    //取消下载,并且存储当前下载的数据
    [self.downloadTask cancelByProducingResumeData:^(NSData *resumeData) {
        self.data = resumeData;
    }];
    //如果点击多次暂停 会出问题  无法继续(因为 点击多次暂停的话 resumeData 为空)
    self.downloadTask = nil;
  
}
//继续下载
- (IBAction)resume:(id)sender {
    if (self.data == nil) {
        NSLog(@"没有要继续的数据");
        return;
    }
   
    [[self.session downloadTaskWithResumeData:self.data] resume];
   
    self.data = nil;
}
- (void)download{
//    NSString *strUrl = @"http://127.0.0.1/A02-head.mp4";
    NSString *strUrl = @"http://dlsw.baidu.com/sw-search-sp/soft/9d/25765/sogou_mac_31.1421982306.dmg";
    strUrl = [strUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSURL *url = [NSURL URLWithString:strUrl];
    //使用代理的话,不能用此方法 
//    [[self.session downloadTaskWithURL:url completionHandler:^(NSURL *location, NSURLResponse *response, NSError *error) {
//        NSLog(@"---%@",[NSThread currentThread]);
//    }] resume];
   
    //执行代理方法
    self.downloadTask = [self.session downloadTaskWithURL:url];
    [self.downloadTask resume];
//     [[self.session downloadTaskWithURL:url] resume];
}

//代理的方法
 
//下载完成  —————>>>  didFinishDownloadingToURL
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location{
    NSLog(@"over");
}
//断点续传    ————>>>  didResumeAtOffset
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes{
    NSLog(@"==");
}
//进度
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite{
    NSLog(@"---%@",[NSThread currentThread]);

//    [NSThread sleepForTimeInterval:0.1];
    //bytesWritten 本次下载了多少
    //totalBytesWritten  总共下载了多少
    //totalBytesExpectedToWrite  文件的大小
    float process = totalBytesWritten * 1.0 / totalBytesExpectedToWrite;
    NSLog(@"%f", process);
    self.processView.progress = process;
   
}
 
@end
原文地址:https://www.cnblogs.com/supersr/p/4854337.html