我的应用正在使用网络连接,如下所示:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
.
.
.
receivedData = [[NSMutableData alloc] init];
}
.
-(void) dataFromWeb{
request = [[NSURLRequest alloc] initWithURL: url];
theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
if (theConnection) {
receivedData = [[NSMutableData data] retain];
NSLog(@"** NSURL request sent !");
} else {
NSLog(@"Connection failed");
}
.
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
.
.
.
[theConnection release];
[request release];
// Here - using receivedData
[receivedData release];
}
.
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[receivedData setLength:0];
}
.
- (void)connection:(NSURLConnection *)connection
didFailWithError:(NSError *)error
{
[theConnection release];
[request release];
[receivedData release];
}
.
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[receivedData appendData:data];
}
.在应用程序的后面是这个片段 (onButtonPressed):
if (theConnection) {
// Create the NSMutableData to hold the received data.
// receivedData is an instance variable declared elsewhere.
receivedData = [[NSMutableData data] retain];
} else {
NSLog(@"Connection failed");
}
我想理解的是:
如果我想同时创建另一个 URLRequest,我是否需要使用不同的连接以使来自网络的数据在检索时不会混淆?
在这段代码中,当应用程序崩溃时,有时代码会在函数 didReceiveResponse()
setLength:0
的行崩溃我看到receivedData=nil
我应该将行更改为if(receivedData!=nil) [receivedData setLength:0]; else receivedData = [[NSMutableData data] retain];
我不太确定这一行在做什么 receivedData = [[NSMutableData data] retain];
最佳答案
我认为处理 2 个连接的最简单方法是复制 NSMutableData
。我以这种方式使用,它非常适合我。
拳头你在你想要第二个连接的地方这样做:
receivedData2 = [[NSMutableData alloc] init];
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
if (receivedData2) {
[receivedData2 setLength:0];
}
else
{
[receivedData setLength:0];
}
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
if (receivedData2) {
[receivedData2 appendData:data];
}
else {
[receivedData appendData:data];
}
}
然后,在您请求 receivedData2 或 receivedData 的方法中
当你使用它时不要忘记做:
receivedData2=nil;
[receivedData2 setLength:0];
关于objective-c - 处理网络连接的正确方法是什么?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/13510571/