在我的程序中,我有一个 NSMutableData 变量,用于收集来自 http://www.nhara.org/scored_races-2013.htm 的信息。 .大约第三次从网站获取信息后,当它包含 90810 字节时,它要么消失,要么变成 null,因为如果我将其打印为 NSString,它就是 null。这是代码
- (void)viewWillAppear:(BOOL)animated
{
// Create a new data container for the stuff that comes back from the service
xmlData = [[NSMutableData alloc] initWithCapacity:180000];
[self fetchEntries];
[super viewWillAppear:animated];
}
- (void)fetchEntries
{
// Construct a URL that will ask the service for what you want
NSURL *url = [NSURL URLWithString: @"http://www.nhara.org/scored_races-2013.htm"];//
// Put that URL into an NSURLRequest
NSURLRequest *req = [NSURLRequest requestWithURL:url];
// Create a connection that will exchange this request for data from the URL
connection = [[NSURLConnection alloc] initWithRequest:req delegate:self startImmediately:YES];
}
- (void)connection:(NSURLConnection *)conn didReceiveData:(NSData *)data
{
// Add the incoming chunk of data to the container we are keeping
// The data always comes in the correct order
[xmlData appendData:data];
NSLog(@"%@",xmlData);
NSString *xmlCheck = [[[NSString alloc] initWithData:xmlData encoding:NSUTF8StringEncoding]autorelease];
NSLog(@"xmlCheck = %@", xmlCheck);
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(@"error= %@",error);
}
- (void)connectionDidFinishLoading:(NSURLConnection *)conn {
// We are just checking to make sure we are getting the XML
NSString *xmlCheck = [[[NSString alloc] initWithData:xmlData encoding:NSUTF8StringEncoding] autorelease];
NSLog(@"xmlCheck2 = %@", xmlCheck);
}
最让我困惑的是我的 NSMutableData 存储数据,但随后在声称具有相同字节数的同时丢失了数据。
NSMutableData 的大小是否有限制,或者我的问题只是内存管理?
您需要为 xmlData 变量创建一个属性。在你的头文件中之后 @interface MyClass
,像这样制作一个
@property (nonatomic, retain) NSMutableData * xmlData;
如果您使用 ARC,则将其保留为强,如果您使用以下 ARC,则将强更改为保留。当您想使用变量时,您可以执行 self.xmlData
Tôi là một lập trình viên xuất sắc, rất giỏi!