24-断点续传-NSURLConnection

本文主要是介绍24-断点续传-NSURLConnection，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

//
//  ViewController.m
//  03-大文件下载-断点续传
//
//  Created by 张旗 on 15/5/19.
//  Copyright (c) 2015年 张旗. All rights reserved.
//#import "ViewController.h"
#import "DACircularProgressView.h"@interface ViewController ()<NSURLConnectionDataDelegate>@property (nonatomic, weak) DACircularProgressView *circleView;
@property (nonatomic, assign)long long currentLength;
@property (nonatomic, strong) NSURLConnection *conn;
@property (nonatomic,strong) NSFileHandle *writeHandle;
@property (nonatomic,assign)long long totalLength;@end@implementation ViewController- (void)viewDidLoad {[super viewDidLoad];DACircularProgressView *circleView = [[DACircularProgressView alloc] initWithFrame:CGRectMake(110, 50, 100, 100)];circleView.progressTintColor = [UIColor redColor];circleView.trackTintColor = [UIColor blueColor];circleView.progress = 0.00001;[self.view addSubview:circleView];self.circleView = circleView;
}- (IBAction)beginDownload:(UIButton *)button {button.selected = !button.selected;if (button.selected) {// 下载资源的路径NSURL *url = [NSURL URLWithString:@"http://localhost:8080/MJServer/resources/videos/test.mp4"];NSMutableURLRequest  *request = [NSMutableURLRequest requestWithURL:url];// 设置请求头NSString *range =[NSString stringWithFormat:@"bytes=%lld-",self.currentLength];[request setValue:range forHTTPHeaderField:@"range"];self.conn = [NSURLConnection connectionWithRequest:request delegate:self];}else{NSLog(@"暂停下载");[self.conn cancel];self.conn = nil;}}- (void)didReceiveMemoryWarning {[super didReceiveMemoryWarning];// Dispose of any resources that can be recreated.
}#pragma mark - NSURLConnectionDataDelegate协议中的方法/***  连接失败的时候调用**  @param connection <#connection description#>*  @param error      <#error description#>*/
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
}/***  得到服务器响应的时候调用**  @param connection <#connection description#>*  @param response   <#response description#>*/
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{NSLog(@"得到了服务器端响应");if (self.currentLength) return;// 文件路径NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];NSString *filepath = [caches stringByAppendingPathComponent:@"test.zip"];// 在沙盒中创建一个文件NSFileManager *mgr =[NSFileManager defaultManager];[mgr createFileAtPath:filepath contents:nil attributes:nil];// 创建一个用来写数据的句柄self.writeHandle = [NSFileHandle fileHandleForWritingAtPath:filepath];// 获得文件的总大小self.totalLength = response.expectedContentLength;
}/***  接收服务器端返回的数据**  @param connection <#connection description#>*  @param data       <#data description#>*/
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{NSLog(@"接收数据");// 写的文件句柄移动到文件的最末尾[self.writeHandle seekToEndOfFile];// 将数据写入沙盒[self.writeHandle writeData:data];// 累计文件的长度self.currentLength += data.length;self.circleView.progress = (double)self.currentLength / self.totalLength;
}/***  下载完成**  @param connection <#connection description#>*/
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{NSLog(@"下载完成");self.currentLength = 0;self.totalLength = 0;// 关闭文件[self.writeHandle closeFile];self.writeHandle = nil;
}
@end

这篇关于24-断点续传-NSURLConnection的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！

---