Objective c 如何从NSMutableData获取数组

我有5个字符串的文本文件。我需要使用NSURLConnection来获取此文件的内容。但NSLog告诉我，“转储”是空的。如何将数据从NSMutableData转换到NSArray。数组是因为我需要在TableView中显示这5项

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;

---

提前谢谢。顺便说一句，URL起作用，您可以查看文件。

您必须使用委托，然后将接收到的数据保存到receivedData（现在当然是空的..您只是初始化了它。）然后将数据转换为字符串，就像您在示例中所做的那样。查看一下

nsurlconnectionelegate

您需要为NSURLConnection实现委托方法，以便收到传入数据的通知。您正在使用异步方法

还要注意，

[NSMutableData]

只创建了一个空数据对象。。所以你不能期望它包含任何数据

我建议你读一读

---

（完全！）

如果您不想使用委托，可以使用NSURLConnection的同步调用，如下所示：

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;
}

---

请注意，这不会异步运行。如果您不希望它在主线程上运行并阻止主线程/ UI，请考虑使用单独的线程来执行该代码或使用GCD。

< P>这里您是如何用委托实现这个解决方案：

在.h文件中：

@interface MyClass : NSObject <NSURLConnectionDelegate, NSURLConnectionDataDelegate>

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

@end

---

当您使用分配空对象的构造函数创建c

receivedData

时，为什么希望

dump

为非空？谢谢，它对我很有用。但它在委派时必须是什么样子呢？这是一个更复杂的解决方案。让我看看是否能找到一个例子。我添加了第二个答案，使用委托。

@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