iOS利用AFNetworking3.0――实现文件断点下载

#import "AFNetworking.h"

 @interface ViewController ()

{

 // 下载句柄

 NSURLSessionDownloadTask *_downloadTask;

} 

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

// 下载文件显示

@property (weak, nonatomic) IBOutlet UIImageView *imageView;

// 下载进度条显示

@property (weak, nonatomic) IBOutlet UIProgressView *progressView;

@end

@interface ViewController ()

{

 // 下载句柄

 NSURLSessionDownloadTask *_downloadTask;

} 

- (void)downFileFromServer{

 //远程地址

 NSURL *URL = [NSURL URLWithString:@"http://www.baidu.com/img/bdlogo.png"];

 //默认配置

 NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];

 

 //AFN3.0+基于封住URLSession的句柄

 AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:configuration];

 

 //请求

 NSURLRequest *request = [NSURLRequest requestWithURL:URL];

 

 //下载Task操作

 _downloadTask = [manager downloadTaskWithRequest:request progress:^(NSProgress * _Nonnull downloadProgress) {

  

  // @property int64_t totalUnitCount;  需要下载文件的总大小

  // @property int64_t completedUnitCount; 当前已经下载的大小

  

  // 给Progress添加监听 KVO

  NSLog(@"%f",1.0 * downloadProgress.completedUnitCount / downloadProgress.totalUnitCount);

  // 回到主队列刷新UI

  dispatch_async(dispatch_get_main_queue(), ^{

  // 设置进度条的百分比

 

   self.progressView.progress = 1.0 * downloadProgress.completedUnitCount / downloadProgress.totalUnitCount;

  });

 

 } destination:^NSURL * _Nonnull(NSURL * _Nonnull targetPath, NSURLResponse * _Nonnull response) {

  

  //- 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

 

  NSString *cachesPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];

  NSString *path = [cachesPath stringByAppendingPathComponent:response.suggestedFilename];

  return [NSURL fileURLWithPath:path];

 

 } completionHandler:^(NSURLResponse * _Nonnull response, NSURL * _Nullable filePath, NSError * _Nullable error) {

  //设置下载完成操作

  // 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

  

  NSString *imgFilePath = [filePath path];// 将NSURL转成NSString

  UIImage *img = [UIImage imageWithContentsOfFile:imgFilePath];

  self.imageView.image = img;

 

 }];

} 

- (IBAction)stopDownloadBtnClick:(id)sender {

 //暂停下载

 [_downloadTask suspend];

}

- (IBAction)startDownloadBtnClick:(id)sender {

 //开始下载

 [_downloadTask resume];

} 

- (void)viewDidLoad {

 [super viewDidLoad];

 

 //网络监控句柄

 AFNetworkReachabilityManager *manager = [AFNetworkReachabilityManager sharedManager];

 

 //要监控网络连接状态，必须要先调用单例的startMonitoring方法

 [manager startMonitoring];

 

 [manager setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {

  //status:

  //AFNetworkReachabilityStatusUnknown   = -1, 未知

  //AFNetworkReachabilityStatusNotReachable  = 0, 未连接

  //AFNetworkReachabilityStatusReachableViaWWAN = 1, 3G

  //AFNetworkReachabilityStatusReachableViaWiFi = 2, 无线连接

  NSLog(@"%d", status);

 }];

 

 //准备从远程下载文件. -> 请点击下面开始按钮启动下载任务

 [self downFileFromServer];

 

}