xcode 下载前计算文件大小
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Calculating File size before download
提问by Sagar R. Kothari
What I want to do is explained as follows.
我想要做的解释如下。
I have an url of MP3 file. ( for example Sound File)
我有一个 MP3 文件的网址。（例如声音文件）
When user starts application, download should start & for that I have implemented following methods:
当用户启动应用程序时，下载应该开始，为此我已经实现了以下方法：
-(void)viewDidLoad {
[super viewDidLoad];
NSURL *url=[NSURL URLWithString:@"http://xyz.pqr.com/abc.mp3"];
NSURLRequest *req=[NSURLRequest requestWithURL:url cachePolicy:NSURLCacheStorageNotAllowed timeoutInterval:120];
NSURLConnection *con=[[NSURLConnection alloc] initWithRequest:req delegate:self startImmediately:YES];
if(con){
myWebData=[[NSMutableData data] retain];
} else {
// [MainHandler performSelector:@selector(targetSelector:) withObject:nil];
}
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
NSLog(@"%@",@"connection established");
[myWebData setLength: 0];
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
NSLog(@"%@",@"connection receiving data");
[myWebData appendData:data];
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
NSLog(@"%@",@"connection failed");
[connection release];
// [AlertViewHandler showAlertWithErrorMessage:@"Sorry, there is no network connection. Please check your network and try again."];
// [self parserDidEndDocument:nil];
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection {
[connection release];
}
Above methods work perfectly for downloading. But I can not get the exact size which is going to be downloaded. I want to know what is the size of file - which is going to be download.
以上方法非常适合下载。但我无法获得将要下载的确切大小。我想知道要下载的文件的大小。
回答by FKDev
Just use the expectedContentSize on the NSURLResponseobject which is passed to the following delegate methods:
只需在NSURLResponse传递给以下委托方法的对象上使用 expectedContentSize ：
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
}
-(NSURLRequest *)connection:(NSURLConnection *)connection
willSendRequest:(NSURLRequest *)request
redirectResponse:(NSURLResponse *)response {
}
like this:
像这样：
long long size = [response expectedContentLength];
回答by Sagar R. Kothari
Yep ! Almost done with ASIHTTP.
是的 ！几乎完成了 ASIHTTP。
-(IBAction)btnTapped:(id)sender {
NSURL *url = [NSURL URLWithString:@"http://sound20.mp3pk.com/indian/omkara/omkara1%28songs.pk%29.mp3"];
ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
[request setDownloadDestinationPath:[self pathForLogInCCID]];
[myProgressIndicator setProgress:0];
[request setDownloadProgressDelegate:myProgressIndicator];
[request startSynchronous];
[myProgressIndicator doubleValue]);
[request setDelegate:self];
[request startAsynchronous];
}
- (void)requestFinished:(ASIHTTPRequest *)request
{
// Use when fetching text data
// NSString *responseString = [request responseString];
// Use when fetching binary data
// NSData *responseData = [request responseData];
}
- (void)requestFailed:(ASIHTTPRequest *)request
{
// NSError *error = [request error];
}
-(NSString*)pathForLogInCCID{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *DataPath = [documentsDirectory stringByAppendingPathComponent:@"mySong.png"];
return DataPath;
}
