3

私は初心者ですNSURLConnection。Google で検索してこのサイトを見つけましたが、よくわかりません。

私の友人は、Document フォルダの URL からダウンロードしたコードについて説明してください。

これは私のコードです:

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSURL *url =[NSURL URLWithString:@"http://cdn.arstechnica.net/wp-content/uploads/2012/09/iphone5-intro.jpg"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    NSURLConnection *con  = [[NSURLConnection alloc]initWithRequest:request delegate:self];
    [con start];}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    //I dont know what thing put here
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)theData
{
    //I dont know what thing put here
}


- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    //I dont know what thing put here
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    UIAlertView *errorView = [[UIAlertView alloc]initWithTitle:@"Error" message:@"The Connection has been LOST" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
    [errorView show];
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}
4

3 に答える 3

5

NSURLConnectionを使用して、これを試してください

// Create the request.
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://cdn.cultofmac.com/wp-content/uploads/2013/03/colorware-iphone-5-xl.jpg"]
                        cachePolicy:NSURLRequestUseProtocolCachePolicy
                    timeoutInterval:60.0];
// create the connection with the request
// and start loading the data
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if (theConnection) {
    // Create the NSMutableData to hold the received data.
    // receivedData is an instance variable declared elsewhere.
    receivedData = [[NSMutableData data] retain];
} else {
    // Inform the user that the connection failed.
}

NSURLConnection の詳細については、これを参照してください: URL ローディング システム プログラミング ガイド

編集

これrecievedDataは型のインスタンス変数ですNSMutableData

-(void)downloadWithNsurlconnection
{

    NSURL *url = [NSURL URLWithString:currentURL];
    NSURLRequest *theRequest = [NSURLRequest requestWithURL:url         cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:60];
    receivedData = [[NSMutableData alloc] initWithLength:0];
    NSURLConnection * connection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self     startImmediately:YES];


}


- (void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    [receivedData setLength:0];
}

- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [receivedData appendData:data];


}

- (void) connectionDidFinishLoading:(NSURLConnection *)connection {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *pdfPath = [documentsDirectory stringByAppendingPathComponent:[currentURL stringByAppendingString:@".jpg"]];
    NSLog(@"Succeeded! Received %d bytes of data",[receivedData length]);
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    [receivedData writeToFile:pdfPath atomically:YES];
}
于 2013-05-09T05:14:13.630 に答える
2

使用しなくてNSURLConnectionも、ファイルを簡単にダウンロードできるため、デリゲート呼び出しをオーバーヘッドする必要はありません。これを試してみてください。

NSString *url = @"http://cdn.cultofmac.com/wp-content/uploads/2013/03/colorware-iphone-5-xl.jpg";
NSArray *path               = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentdirectory = [path objectAtIndex:0];
NSString *dataPath          = [documentdirectory stringByAppendingPathComponent:@"Pictures"];
NSString *localFileURL      = [NSString stringWithFormat:@"%@/%@",dataPath,[url lastPathComponent]];

if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
[[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:nil];

NSData   *data         = [NSData dataWithContentsOfURL:[NSURL URLWithString:url]];
if([data writeToFile:localFileURL atomically:YES])
{
    NSLog(@"Downloaded File");
}
于 2013-05-09T05:10:12.453 に答える