#import "ViewController.h"@interface ViewController ()<NSURLSessionDownloadDelegate,NSURLSessionDownloadDelegate>
///显示图片的
@property (weak, nonatomic) IBOutlet UIImageView *imageView;
///显示进度的
@property (weak, nonatomic) IBOutlet UISlider *progressView;
///下载任务的属性
@property (nonatomic,strong)NSURLSessionDownloadTask *task;
///网络请求类
@property
(nonatomic,strong)NSURLSession *session;///发送请求类
@property(nonatomic,strong)NSURLRequest *request;
///用于保存已经下载的数据的，供继续下载使用@property (nonatomic,strong)NSMutableData *data;@end@implementation ViewController- (void)viewDidLoad {[super viewDidLoad];// Do any additional setup after loading the view, typically from a nib.//self.progressView.value = 0;
}
#pragma mark - 开始下载
- (IBAction)startDownLoad:(id)sender {NSString *urlStr = @"https://ss0.bdstatic.com/94oJfD_bAAcT8t7mm9GUKT-xh_/timg?image&quality=100&size=b4000_4000&sec=1464602004&di=2f52d829b167189d005b506a96fbd87e&src=http://imgsrc.baidu.com/forum/pic/item/b15db8a1cd11728b829819d0c8fcc3cec2fd2c6c.jpg";NSURL *url = [NSURL URLWithString:urlStr];//初始化请求self.request = [NSURLRequest requestWithURL:url];//创建NSURLSessionNSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];self.session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:[NSOperationQueue mainQueue]];
//    NSURLSessionTask *task = [session dataTaskWithRequest:self.request];//下载请求任务self.task = [self.session downloadTaskWithRequest:self.request];//开启[_task resume];}
#pragma mark - 暂停下载
- (IBAction)pauseDownLoad:(id)sender {//暂停if (self.task ) {//暂停并保存之前已经下载的内容__weak typeof(self)weakSelf = self;[self.task cancelByProducingResumeData:^(NSData * _Nullable resumeData) {weakSelf.data = [NSMutableData dataWithData:resumeData];}];}//暂停任务[_task suspend];
}
#pragma mark - 继续下载
- (IBAction)continueDownLoad:(id)sender {//判断当前任务是否有，是发送请求还是处理数据if (self.task != nil) {//说明已经下载，这里要处理的就是数据self.task = [self.session downloadTaskWithResumeData:self.data];} else {//此时没有下载任何内容，应该重新发送请求进行下载self.task = [self.session downloadTaskWithRequest:self.request];}//启动[self.task resume];
}#pragma mark - 代理方法
//下载完成走的方法
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location {NSLog(@"%@",location);// 设置文件的存放目标路径NSString *documentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject;NSURL *documentsDirectoryURL = [NSURL fileURLWithPath:documentsPath];NSURL *fileURL = [documentsDirectoryURL URLByAppendingPathComponent:[[downloadTask.response URL] lastPathComponent]];//使用// 如果该路径下文件已经存在，就要先将其移除，在移动文件NSFileManager *fileManager = [NSFileManager defaultManager];if ([fileManager fileExistsAtPath:[fileURL path] isDirectory:NULL]) {[fileManager removeItemAtURL:fileURL error:NULL];}//让documents文件也有一份下载的文件[fileManager moveItemAtURL:location toURL:fileURL error:NULL];self.imageView.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:fileURL]];NSLog(@"%@",fileURL);
}
//下载中
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite {//下载当前段的数据NSLog(@"bytesWritten=%lld",bytesWritten);//已经下载的总数据量NSLog(@"totalBytesWritten=%lld",totalBytesWritten);//总进度NSLog(@"totalBytesExpectedToWrite=%lld",totalBytesExpectedToWrite);//设置progressView的进度值self.progressView.value = (CGFloat)totalBytesWritten/(CGFloat)totalBytesExpectedToWrite;
}@end