iOS- 利用AFNetworking3.0+（最新AFN) - 实现文件断点下载

0.导入框架准备工作　　

            1
            @interface
             ViewController ()

            2
            {

            3
            //
             下载句柄
            4     NSURLSessionDownloadTask *_downloadTask;
5 }

             1
            .h文件

             2
            #import <UIKit/UIKit.h>
 3 4@interface ViewController : UIViewController
 5// 下载文件显示 6 7 @property (weak, nonatomic) IBOutlet UIImageView *imageView;
 8// 下载进度条显示 910 @property (weak, nonatomic) IBOutlet UIProgressView *progressView;
11@end1213.m文件
14@interface ViewController ()
15{
16// 下载句柄17     NSURLSessionDownloadTask *_downloadTask;
18 } 

             1 - (void)downFileFromServer{
 2 3//远程地址 4     NSURL *URL = [NSURL URLWithString:@"http://www.baidu.com/img/bdlogo.png"];
 5//默认配置 6     NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
 7 8//AFN3.0+基于封住URLSession的句柄 9     AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:configuration];
1011//请求12     NSURLRequest *request = [NSURLRequest requestWithURL:URL];
1314//下载Task操作15     _downloadTask = [manager downloadTaskWithRequest:request progress:^(NSProgress * _Nonnull downloadProgress) {
1617// @property int64_t totalUnitCount;     需要下载文件的总大小
18// @property int64_t completedUnitCount; 当前已经下载的大小
1920// 给Progress添加监听 KVO21         NSLog(@"%f",1.0 * downloadProgress.completedUnitCount / downloadProgress.totalUnitCount);
22// 回到主队列刷新UI23         dispatch_async(dispatch_get_main_queue(), ^{
24// 设置进度条的百分比2526             self.progressView.progress = 1.0 * downloadProgress.completedUnitCount / downloadProgress.totalUnitCount;
27        });
2829     } destination:^NSURL * _Nonnull(NSURL * _Nonnull targetPath, NSURLResponse * _Nonnull response) {
3031//- block的返回值, 要求返回一个URL, 返回的这个URL就是文件的位置的路径3233         NSString *cachesPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
34         NSString *path = [cachesPath stringByAppendingPathComponent:response.suggestedFilename];
35return [NSURL fileURLWithPath:path];
3637     } completionHandler:^(NSURLResponse * _Nonnull response, NSURL * _Nullable filePath, NSError * _Nullable error) {
38//设置下载完成操作
39// filePath就是你下载文件的位置，你可以解压，也可以直接拿来使用4041         NSString *imgFilePath = [filePath path];// 将NSURL转成NSString42         UIImage *img = [UIImage imageWithContentsOfFile:imgFilePath];
43         self.imageView.image = img;
4445    }];
46 }

            1 - (IBAction)stopDownloadBtnClick:(id)sender {
2//暂停下载3    [_downloadTask suspend];
4}
5 - (IBAction)startDownloadBtnClick:(id)sender {
6//开始下载7    [_downloadTask resume];
8 }

             1 - (void)viewDidLoad {
 2    [super viewDidLoad];
 3 4//网络监控句柄 5     AFNetworkReachabilityManager *manager = [AFNetworkReachabilityManager sharedManager];
 6 7//要监控网络连接状态，必须要先调用单例的startMonitoring方法 8    [manager startMonitoring];
 910     [manager setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
11//status:
12//AFNetworkReachabilityStatusUnknown          = -1,  未知
13//AFNetworkReachabilityStatusNotReachable     = 0,   未连接
14//AFNetworkReachabilityStatusReachableViaWWAN = 1,   3G
15//AFNetworkReachabilityStatusReachableViaWiFi = 2,   无线连接16         NSLog(@"%d", status);
17    }];
1819//准备从远程下载文件. -> 请点击下面开始按钮启动下载任务20    [self downFileFromServer];
2122 }