在lable中显示string时应用崩溃

在用NSString更新UILabel时应用崩溃了，在console中显示同样的NSString就没问题：

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    if (self.connectionData)
    {
        NSError *error;
        self.dict = [NSJSONSerialization JSONObjectWithData:self.connectionData options:kNilOptions error:&error];
        self.matchesArray = self.dict[@"matches"];

        NSString *title = [self.matchesArray valueForKey:@"title"];
        NSLog(@"NSString TITLE contains: %@", title);
        self.titleLabel.text = title;
    }
}

CONSOLE OUTPUT:

2013-01-16 13:54:08.550 ZEITreisen[3168:c07] NSString TITLE contains: (
    "Mark und Dollar"
)
2013-01-16 13:54:08.552 ZEITreisen[3168:c07] -[__NSArrayI isEqualToString:]: unrecognized selector sent to instance 0xde93850
(lldb) 

试试：

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    if (self.connectionData)
    {
        NSError *error;
        self.dict = [NSJSONSerialization JSONObjectWithData:self.connectionData options:kNilOptions error:&error];
        self.matchesArray = self.dict[@"matches"];

        NSString *title = [self.matchesArray valueForKey:@"title"];
        NSLog(@"NSString TITLE contains: %@", title);
        self.titleLabel.text = [NSString stringWithFormat:@"%@",[title objectAtIndex:0]];
    }
}

title 不属于NSString, 它其实是NSArray

所以改成这样：

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    if (self.connectionData)
    {
        NSError *error;
        self.dict = [NSJSONSerialization JSONObjectWithData:self.connectionData options:kNilOptions error:&error];
        self.matchesArray = self.dict[@"matches"];

        NSArray *title = [self.matchesArray valueForKey:@"title"];
        NSLog(@"NSString TITLE contains: %@", title);
        self.titleLabel.text = [title lastObject];
    }
}