iOS开发 大文件下载封装

时间：2021-12-09 20:58:35

iOS开发 文件下载

功能：实现文件的断点下载，即暂停，开始

完整源码:   http://download.csdn.net/detail/u010029229/9164147

下载封装类：MyFileDownloader.h MyFileDownloader.m

//
//  MyFileDownloader.h
//  大文件下载封装
//
//  Created by Qianfeng on 15/10/8.
//  Copyright (c) 2015年 xyz. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface MyFileDownloader : NSObject

// 下载文件URL
@property (nonatomic, copy) NSString *url;

// 文件存储路径
@property (nonatomic, copy) NSString *destPath;

// 是否正在下载
@property (nonatomic, readonly, getter=isDownloading) BOOL downloading;

// 用来监听下载进度
@property (nonatomic, copy) void(^progressHandler)(double progress);

// 监听下载完毕
@property (nonatomic, copy) void (^completionHandler)();

// 监听下载失败
@property (nonatomic, copy) void (^failureHandle)(NSError *error);

// 开始下载
- (void)startDownload;

// 暂停下载
- (void)pauseDownload;

@end

//
//  MyFileDownloader.m
//  大文件下载封装
//
//  Created by Qianfeng on 15/10/8.
//  Copyright (c) 2015年 xyz. All rights reserved.
//

#import "MyFileDownloader.h"

@interface MyFileDownloader()<NSURLConnectionDataDelegate>
@property (nonatomic, strong) NSURLConnection *conn; // 链接对象
@property (nonatomic, strong) NSFileHandle *writeHandle; // 写文件句柄
@property (nonatomic, assign) long long currentLength; // 当前文件总长度
@property (nonatomic, assign) long long totalLength; // 文件总长度
@end


@implementation MyFileDownloader

- (void)startDownload {
    NSURL *url = [NSURL URLWithString:self.url];
    // 默认就是GET请求
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    // 设置请求头信息
    NSString *value = [NSString stringWithFormat:@"bytes=%lld-", self.currentLength];
    [request setValue:value forHTTPHeaderField:@"Range"];
    self.conn = [NSURLConnection connectionWithRequest:request delegate:self];

    _downloading = YES;
}

- (void)pauseDownload {
    [self.conn cancel];
    self.conn = nil;

    _downloading = NO;
}

#pragma mark - NSURLConnectionDataDelegate 代理方法
/**
 *  1. 当接受到服务器的响应(连通了服务器)就会调用
 */
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    if (self.totalLength) return;

    // 1.创建一个空的文件到沙盒中
    NSFileManager *mgr = [NSFileManager defaultManager];
    // 刚创建完毕的大小是0字节
    [mgr createFileAtPath:self.destPath contents:nil attributes:nil];

    // 2.创建写数据的文件句柄
    self.writeHandle = [NSFileHandle fileHandleForWritingAtPath:self.destPath];

    // 3.获得完整文件的长度
    self.totalLength = response.expectedContentLength;
}

/**
 *  2. 当接受到服务器的数据就会调用(可能会被调用多次, 每次调用只会传递部分数据)
 */
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    // 累加长度
    self.currentLength += data.length;

    // 显示进度
    double progress = (double)self.currentLength / self.totalLength;
    if (self.progressHandler) { // 传递进度值给block
        self.progressHandler(progress);
    }

    // 移动到文件的尾部
    [self.writeHandle seekToEndOfFile];
    // 从当前移动的位置(文件尾部)开始写入数据
    [self.writeHandle writeData:data];
}

/**
 *  3. 当服务器的数据接受完毕后就会调用
 */
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    // 清空属性值
    self.currentLength = 0;
    self.totalLength = 0;

    if (self.currentLength == self.totalLength) {
        // 关闭连接(不再输入数据到文件中)
        [self.writeHandle closeFile];
        self.writeHandle = nil;
    }

    if (self.completionHandler) {
        self.completionHandler();
    }
}

/**
 *  请求错误(失败)的时候调用(请求超时\断网\没有网, 一般指客户端错误)
 */
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    if (self.failureHandle) {
        self.failureHandle(error);
    }
}


@end

控制器源码

//
//  ViewController.h
//  大文件下载封装
//
//  Created by Qianfeng on 15/10/8.
//  Copyright (c) 2015年 xyz. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController


@end


//
//  ViewController.m
//  大文件下载封装
//
//  Created by Qianfeng on 15/10/8.
//  Copyright (c) 2015年 xyz. All rights reserved.
//

#import "ViewController.h"
#import "MyFileDownloader.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIProgressView *progressView;
@property (nonatomic, strong) MyFileDownloader *fileDownloader;
- (IBAction)startDownloader:(id)sender;
@property (weak, nonatomic) IBOutlet UIButton *button;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.progressView.progress = 0;
}

- (MyFileDownloader *)fileDownloader
{
    if (!_fileDownloader) {
        _fileDownloader = [[MyFileDownloader alloc] init];

        NSString *url = @"http://10.0.8.8/download/MapKit-LBS项目-FindMe.pdf";


        // 需要下载的文件远程URL
        _fileDownloader.url = [url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
        // 文件保存到什么地方
        NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
        NSString *filepath = [caches stringByAppendingPathComponent:@"abc.pdf"];
        _fileDownloader.destPath = filepath;
        //        typeof(10) a = 20; // int a = 20;

        __weak typeof(self) vc = self;
        _fileDownloader.progressHandler = ^(double progress) {
            vc.progressView.progress = progress;
        };

        _fileDownloader.completionHandler = ^{
            NSLog(@"------下载完毕");
        };

        _fileDownloader.failureHandle = ^(NSError *error){

        };
    }
    return _fileDownloader;
}
- (IBAction)startDownloader:(id)sender {
    if (self.fileDownloader.isDownloading) { // 暂停下载
        [self.fileDownloader pauseDownload];

        [self.button setTitle:@"恢复" forState:UIControlStateNormal];
    } else { // 开始下载
        [self.fileDownloader startDownload];

        [self.button setTitle:@"暂停" forState:UIControlStateNormal];
    }
}
@end
在控制器的那两个控件就自己看着办吧。。。

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