如何在浏览视图控制器时获取当前正在运行的NSURLSession后台会话？
如何在浏览视图控制器时获取当前正在运行的NSURLSession后台会话？
提问于 2014-05-20 11:51:21
我正在开发一个用于从服务器下载文件(<10MB)的iOS应用程序。我使用NSURLSession和NSURLSessionDownloadTask进行下载。
我的问题是，下载视图控制器不是rootViewController。当我返回到根视图控制器时，我可以看到下载进度仍然在工作(从NSLog)。但是当我再次移动到下载视图控制器时，我看不到我的标签根据进度更新。在这种情况下，我如何让当前正在运行的NSURLSession后台会话更新我的状态标签？或任何其他解决方案？
//Start downloading
-(void)startDownload: (NSString *)url{
NSString *sessionId = MY_SESSION_ID;
NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfiguration backgroundSessionConfiguration:sessionId];
sessionConfiguration.HTTPMaximumConnectionsPerHost = 1;
self.session = [NSURLSession sessionWithConfiguration:sessionConfiguration
delegate:self
delegateQueue:nil];
self.downloadTask = [self.session downloadTaskWithURL:[NSURL URLWithString:url]];
[self.downloadTask resume];
}
//Delegate
-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite{
if (totalBytesExpectedToWrite == NSURLSessionTransferSizeUnknown) {
NSLog(@"Unknown transfer size");
}
else{
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
NSInteger percentage = (double)totalBytesWritten * 100 / (double)totalBytesExpectedToWrite;
self.percentageLabel.text = [NSString stringWithFormat:@"Downloading (%ld%%)", (long)percentage];
NSLog(@"Progress: %ld", (long)percentage);
}];
}
}回答 1
Stack Overflow用户
发布于 2014-07-25 17:18:46
这是我在我的代码中做的，它起作用了：
[self performSelectorOnMainThread:@selector(setuploadStatus:) withObject:NSString stringWithFormat：@“上传%ld%%"，(long)percentage waitUntilDone:否]；
-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didSendBodyData:(int64_t)bytesSent totalBytesSent:(int64_t)totalBytesSent totalBytesExpectedToSend:(int64_t)totalBytesExpectedToSend {
NSInteger percentage = (double)totalBytesSent * 100 / (double)totalBytesExpectedToSend;
**[self performSelectorOnMainThread:@selector(setuploadStatus:) withObject:[NSString stringWithFormat:@"Upload %ld%%", (long)percentage] waitUntilDone:NO];**
NSLog(@"Upload %ld%% ",(long)percentage);
}
-(void) setuploadStatus : (NSString *) setStat {
[_notifyTextLabel setText:setStat];
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/23750720
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