Question:
I use this code to load pictures
-(IBAction) downloadButton:(id)sender {
if(_downloadTask == nil){
_url1 =[NSURL URLWithString:@"someUrl"];
_url2 =[NSURL URLWithString:@"someUrl"];
_downloadTask = [_session downloadTaskWithURL:_url1];
_downloadTask1 = [_session downloadTaskWithURL:_url2];
[_downloadTask resume];
[_downloadTask1 resume];
}
else
[_downloadTask resume];
[_downloadView removeFromSuperview];
[_downloadButton removeFromSuperview];
[_downloadButtonCancel removeFromSuperview];
}
}
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location
{
_paths1 = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
_documentsDirectory1 = [_paths1 objectAtIndex:0];
_filePath1 = [_documentsDirectory1 stringByAppendingPathComponent:@"1.png"];
_fileExists1 = [[NSFileManager defaultManager] fileExistsAtPath:_filePath1 isDirectory:false];
_paths2 = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
_documentsDirectory2 = [_paths2 objectAtIndex:0];
_filePath2 = [_documentsDirectory2 stringByAppendingPathComponent:@"2.png"];
_fileExists2 = [[NSFileManager defaultManager] fileExistsAtPath:_filePath2 isDirectory:false];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
NSData *urlData1 = [NSData dataWithContentsOfURL:_url1];
[urlData1 writeToFile:_filePath1 atomically:YES];
NSData *urlData2 = [NSData dataWithContentsOfURL:_url2];
[urlData2 writeToFile:_filePath2 atomically:YES];
});
And this code to display the loading progress as a percentage
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite;
{
dispatch_async(dispatch_get_main_queue(), ^{
float progress = [[NSNumber numberWithInteger:totalBytesWritten] floatValue];
float total = [[NSNumber numberWithInteger:totalBytesExpectedToWrite] floatValue];
NSString *percentage = [NSString stringWithFormat:@"%.f%%", ((progress / total) * 100)];
NSLog(@"%.f%%", percentage);
if (!_label) {
_label = [[UILabel alloc] initWithFrame:CGRectMake(300, 130, 42, 19)];
_label.numberOfLines = 1;
_label.baselineAdjustment = UIBaselineAdjustmentAlignBaselines;
_label.adjustsFontSizeToFitWidth = YES;
_label.minimumScaleFactor = 10.0f/12.0f;
_label.clipsToBounds = YES;
_label.backgroundColor = [UIColor clearColor];
_label.textColor = [UIColor whiteColor];
_label.textAlignment = NSTextAlignmentCenter;
[self.view addSubview:_label];
}
_label.text = percentage;
The problem is that the label doesn't show the loading from 1% to 100%. and randomly shows different numbers. How to fix it?
Answer:
So you load two urls at once, so they both show their progress at the same time. You need to either load them one by one, or use the downloadTask parameter: (NSURLSessionDownloadTask *) downloadTask to determine which task it is and change the corresponding label. You can also maintain one general progress for two URLs.