IOS 文件下载之断点续传


//
//  ViewController.m
//  DownLoadBig
//
//  Created by apple on 15/5/5.
//  Copyright (c) 2015年 apple. All rights reserved.
//
#import "ViewController.h"
#import "CircularProgressView/CircleProgressView.h"
#import "CircularProgressView/CircleShapeLayer.h"
@interface ViewController () <NSURLConnectionDataDelegate,UIAlertViewDelegate>
@property (weak, nonatomic) IBOutlet UIProgressView *proView;
@property (nonatomic,strong) NSMutableData *fileData;
@property (nonatomic,assign) long long total;
@property (nonatomic,strong) UIAlertView *alert;
@property (nonatomic,strong) NSFileHandle *wHandle;
@property (nonatomic,assign) long long currentLength;
@property (nonatomic,strong) NSString *urlstr;
@property (nonatomic,strong) CircleProgressView *cproView;
@property (weak, nonatomic) IBOutlet UIButton *downLoad;
@property (nonatomic,strong) NSURLConnection *conn;
@end
@implementation ViewController
- (IBAction)download:(id)sender {
    _downLoad.selected = !_downLoad.isSelected;
    if (_downLoad.selected){
        NSURL *url = [NSURL URLWithString:self.urlstr];
        
//        NSURLRequest *req = [NSURLRequest requestWithURL:url];
        NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];
        NSString *range = [NSString stringWithFormat:@"bytes=%lld-",self.currentLength];
//        [req setValue:range forKey:@"Range"];
        [req setValue:range forHTTPHeaderField:@"Range"];
        
        self.conn = [NSURLConnection connectionWithRequest:req delegate:self];
    }
    else
    {
        [self.conn cancel];
        self.conn = nil;
        
    }
}
- (NSString *)urlstr
{
    if (_urlstr == nil){
        _urlstr = @"http://125.39.68.200/files/2011000000F9723B/xiazai.888rj.com/Soft/T/Thunder_7.9.26.4824_XiaZaiBa.exe";
    }
    return _urlstr;
}
-(NSMutableData *)fileData
{
    
    if (_fileData == nil){
        
        _fileData = [NSMutableData data];
    }
    return _fileData;
}
- (void)viewDidLoad {
    [super viewDidLoad];
//    self.proView.progress = 0.0;
    self.proView.progress = 0;
   
    
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    if (self.currentLength) return;
    NSHTTPURLResponse *res = (NSHTTPURLResponse *)response;
//    NSLog(@"jieshou");
//    NSLog(@"%@%",res.allHeaderFields[@"Content-Length"]);
//     self.total= res.allHeaderFields[@"Content-Length"];
    
    self.total = res.expectedContentLength;
    
    NSString *AppName =  [[self.urlstr componentsSeparatedByString:@"/"] lastObject];
    NSString *cachestr = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
    NSString *filePath = [cachestr stringByAppendingPathComponent:AppName];
    NSFileManager *mgr = [NSFileManager defaultManager];
    
    [mgr createFileAtPath:filePath contents:nil attributes:nil];
    self.wHandle = [NSFileHandle fileHandleForWritingAtPath:filePath];
    
    
    
    
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    
//    [self.fileData appendData:data];
    [self.wHandle seekToEndOfFile];// 寻找文件的末尾偏移量
    [self.wHandle writeData:data];
    self.currentLength += data.length;
    
    self.proView.progress = (double)self.currentLength  / self.total;
    NSLog(@"%lld",self.currentLength);
    
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    
  
//    [self.fileData writeToFile:filePath atomically:YES];
//    /Users/apple/Library/Developer/CoreSimulator/Devices/612DC518-63EA-4614-AA42-30CAECF2B57B/data/Containers/Data/Application/77095FDC-6D9B-4BB6-AC5F-460EB80DBD22/Library/Caches
    long long totalMB = (self.total /1024/1024);
    
    NSString *totalstr = [ NSString stringWithFormat:@"软件总大小：%lldMB",totalMB];
    self.alert = [[UIAlertView alloc]  initWithTitle:@"下载完成" message:totalstr delegate:self cancelButtonTitle:@"ok"  otherButtonTitles: nil ];
    
    [self.alert show];
    
}
@end