下载前计算文件大小答案

【问题标题】：Calculating File size before download下载前计算文件大小
【发布时间】：2023-04-08 14:10:01
【问题描述】：

我想要做的解释如下。

我有一个 MP3 文件的网址。（例如Sound File）

当用户启动应用程序时，应该开始下载，为此我实现了以下方法：

-(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];
}

以上方法非常适合下载。但我无法获得要下载的确切大小。我想知道要下载的文件的大小。

【问题讨论】：

标签： iphone xcode download nsurlconnection

【解决方案1】：

只需在传递给以下委托方法的NSURLResponse 对象上使用 expectedContentSize：

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

}
-(NSURLRequest *)connection:(NSURLConnection *)connection
        willSendRequest:(NSURLRequest *)request
       redirectResponse:(NSURLResponse *)response {
}

像这样：

long long size = [response expectedContentLength];

【讨论】：

【解决方案2】：

是的！ ASIHTTP 几乎完成了。

-(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;
}

【讨论】：