断点下载
今天做了断点下载视频或者MP3，具体实现如下
1、主要应用了NSURLSessionDownloadTask和NSURLSession并且遵循NSURLSessionDownloadDelegate
2、在沙盒目录下创建文件
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString *file = [NSString stringWithFormat:@"%@/%@",_fileName,_sectionName];
NSString *cachesPath = [[paths objectAtIndex:0]stringByAppendingPathComponent:file];
NSFileManager *fileManager = [NSFileManager defaultManager];
BOOL blHave=[[NSFileManager defaultManager] fileExistsAtPath:cachesPath];
if (blHave) {
}else{
if (![fileManager fileExistsAtPath:cachesPath]) {
[fileManager createDirectoryAtPath:cachesPath withIntermediateDirectories:YES attributes:nil error:nil];
}
}
3、初始化下载方法
@property (nonatomic, strong) NSURLSessionDownloadTask * downloadTask;
@property (nonatomic, strong) NSURLSession *session;
NSURL * url = [NSURL URLWithString:_mainUrl];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
//3.创建session
NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
self.session = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:[NSOperationQueue mainQueue]];
//4.创建Task
_downloadTask = [self.session downloadTaskWithRequest:request];
//5.执行Task
[_downloadTask resume];
5、实现代理
-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite
{
//1. 获得文件的下载进度
NSLog(@"%f",1.0 * totalBytesWritten/totalBytesExpectedToWrite);
[self.delegate progress:1.0 * totalBytesWritten/totalBytesExpectedToWrite];
}
/**
* 当恢复下载的时候调用该方法
*
* @param fileOffset 从什么地方下载
* @param expectedTotalBytes 文件的总大小
*/
-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes
{
NSLog(@"%s",__func__);
}
/**
* 当下载完成的时候调用
*
* @param location 文件的临时存储路径
*/
-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location
{
NSArray * typeArray = [_mainUrl componentsSeparatedByString:@"."];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
//定义自己的文件最终位置
NSString *file = [NSString stringWithFormat:@"%@/%@/%@.%@",_fileName,_sectionName,_sectionName,[typeArray lastObject]];
NSString *cachesPath = [[paths objectAtIndex:0]stringByAppendingPathComponent:file];
NSLog(@"文件的最终下载路径 %@",cachesPath);
[[NSFileManager defaultManager]moveItemAtURL:location toURL:[NSURL fileURLWithPath:cachesPath] error:nil];
}
/**
* 请求结束
*/
-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
}
6、断点下载的信息在 [_downloadTask cancelByProducingResumeData:^(NSData * _Nullable resumeData) {
}];里的object.resumData里
可以把该对象存储在本地，下次进来时候取出该对象接着下载
downloadTask = [self.session downloadTaskWithResumeData:_resumData];
#pragma mark - 暂停下载
- (void)pauseDolo{
__weak typeof(self) object = self;
[_downloadTask cancelByProducingResumeData:^(NSData * _Nullable resumeData) {
object.resumData = resumeData;
NSString * resuData = [NSString stringWithFormat:@"%@.Data",_fileName];
[USERDEFALE setValue:resumeData forKey:resuData];
object.downloadTask = nil;
}];
}
#pragma mark - 取消下载
- (void)cancelDolo{
NSString * resuData = [NSString stringWithFormat:@"%@.Data",_fileName];
[USERDEFALE removeObjectForKey:resuData];
[_downloadTask cancel];
}
