nsmutabledataから配列を取得する方法

Question

私は5文字列のテキストファイルを持っています。このファイルの一致を取得するためにnsurlConnectionを使用する必要があります。しかし、nslogは私を示しています、その「dump」は空です。nsmutabledataからnsArrayへのデータを変換する方法配列は、TableViewでこれら5つの項目を表示する必要があるためです。

NSURLRequest *theRequest=[NSURLRequest
                         requestWithURL:[NSURL URLWithString:@"http://dl.dropbox.com/u/25105800/names.txt"]
                         cachePolicy:NSURLRequestUseProtocolCachePolicy
                         timeoutInterval:60.0];

NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if (theConnection) {
    receivedData = [NSMutableData data];
    NSString *dump = [[NSString alloc] initWithData:receivedData
                         encoding:NSUTF8StringEncoding];
    NSLog(@"data: %@", dump);
    NSArray *outputArray=[dump componentsSeparatedByString:@"\n"];
    self.namesArray = outputArray;

.

事前にありがとう。BTW URLは、ファイルを見ることができます。

Answer 1

If you don't want to use a delegate, you can use a synchronous call with NSURLConnection, like this:

NSURLRequest *theRequest=[NSURLRequest
                     requestWithURL:[NSURL URLWithString:@"http://dl.dropbox.com/u/25105800/names.txt"]
                     cachePolicy:NSURLRequestUseProtocolCachePolicy
                     timeoutInterval:60.0];

NSError *error = nil;
NSHTTPURLResponse *response = nil;
NSData *receivedData = [NSURLConnection sendSynchronousRequest:theRequest response:&response error:&error];

if (error == nil) {
    NSString *dump = [[NSString alloc] initWithData:receivedData
                     encoding:NSUTF8StringEncoding];
    NSLog(@"data: %@", dump);
    NSArray *outputArray=[dump componentsSeparatedByString:@"\n"];
    self.namesArray = outputArray;
}

Just beware that this will not be running asynchronously. If you don't want it to run on the main thread and block your main thread/UI, consider using a separate thread to execute that code or use GCD.

Answer 2

Here's how you implement this solution with a delegate:

In your .h file:

@interface MyClass : NSObject <NSURLConnectionDelegate, NSURLConnectionDataDelegate>

@property (nonatomic, retain) NSMutableData *receivedData;
@property (nonatomic, retain) NSArray *namesArray;

@end

In you .m file:

@implementation MyClass

@synthesize receivedData = _receivedData;
@synthesize namesArray = _namesArray;

- (id)init {
    self = [super init];
    if (self) {
        self.receivedData = [NSMutableData data];
        NSURLRequest *theRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://dl.dropbox.com/u/25105800/names.txt"] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
        NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
        [connection start];

    }
    return self;
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    NSLog(@"Received response! %@", response);
}

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

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    NSString *dump = [[NSString alloc] initWithData:self.receivedData encoding:NSUTF8StringEncoding];
    NSLog(@"data: %@", dump);
    self.namesArray = [dump componentsSeparatedByString:@"\n"];
}

@end

Answer 3

You have to use the delegate, then save the received data into receivedData (which is of course empty right now.. you just initalized it.) and then you transform the data into a string, like you did it in your example. Have a look at NSURLConnectionDelegate

Answer 4

You need to implement the delegate methods for NSURLConnection to be notified of incoming data. You are using the asynchronous methods.

Also note that [NSMutableData data] just creates an empty data-object.. so you can't expect it to contain any data..

I suggest you read https://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/URLLoadingSystem/Tasks/UsingNSURLConnection.html#//apple_ref/doc/uid/20001836-BAJEAIEE (completely!)