IOS 網路淺析－（十 NSURLSession下載簡介），iosnsurlsession

IOS 網路淺析－（十 NSURLSession下載簡介），iosnsurlsession

之前本來打算在寫兩個篇幅，但是在這片開寫的時候覺得還是寫一個比較好，有利於理解。NSURLSession下載是通過NSURLSession下載代理實現的，上一片也介紹了代理，之所以沒有介紹下載是因為，我個人覺得容易混淆（應該是我太笨）。這篇隨筆裡將會介紹NSURLSession下載的實現，包括下載的開始，掛起，繼續。希望本片可以給大家帶來點點收穫。下一篇我打算介紹一下AFN畢竟實際開發中AFN才是硬道理。

 

////  ViewController.m//  NSURLSession大檔案下載////  Created by 大歡 on 16/3/21.//  Copyright © 2016年 大歡. All rights reserved.//#import "ViewController.h"@interface ViewController ()<NSURLSessionDownloadDelegate>@property (nonatomic, strong) NSURLSessionDownloadTask * task;@property (nonatomic, strong) NSData * resumeData;@property (nonatomic, strong) NSURLSession * session;@end@implementation ViewController- (IBAction)start:(id)sender {        NSURLSession * session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[[NSOperationQueue alloc] init]];        self.session = session;    self.task = [session downloadTaskWithURL:[NSURL URLWithString:[@"http://192.168.1.200/DOM解析.mp4"stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]];        [self.task resume];}- (IBAction)pause:(id)sender {        //暫停就是將任務掛起        [self.task cancelByProducingResumeData:^(NSData * _Nullable resumeData) {                //儲存已下載的資料        self.resumeData = resumeData;    }];}- (IBAction)resume:(id)sender {        //可以使用ResumeData建立任務        self.task = [self.session downloadTaskWithResumeData:self.resumeData];        //開啟繼續下載    [self.task resume];    }- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.        NSLog(@"%@",NSSearchPathForDirectoriesInDomains(9, 1, 1));}/*   監測臨時檔案下載的資料大小，當每次寫入臨時檔案時，就會調用一次  bytesWritten 單次寫入多少 totalBytesWritten  已經寫入了多少 totalBytesExpectedToWrite 檔案總大小  */- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask      didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWrittentotalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite {        //列印下載百分比    NSLog(@"%f",totalBytesWritten * 1.0 / totalBytesExpectedToWrite);    }//下載完成- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTaskdidFinishDownloadingToURL:(NSURL *)location {            NSString * cachesPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:downloadTask.response.suggestedFilename];        NSFileManager * mgr = [NSFileManager defaultManager];        [mgr moveItemAtURL:location toURL:[NSURL fileURLWithPath:cachesPath] error:NULL];    }- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {        NSLog(@"%@",error);}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end