我有一个应用程序在另一个线程上使用NSStream连接到服务器。如果用户决定退出,应用程序也会关闭连接。问题是我永远无法在用户断开连接时成功关闭流或线程。下面是关于我如何为网络创建线程并尝试关闭流的代码示例:
+ (NSThread*)networkThread
{
static NSThread *networkThread = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
networkThread = [[NSThread alloc] initWithTarget:self selector:@selector(networkThreadMain:) object:nil];
[networkThread start];
});
return networkThread;
}
+ (void)networkThreadMain:(id)sender
{
while (YES)
{
@autoreleasepool {
[[NSRunLoop currentRunLoop] run];
}
}
}
- (void)scheduleInThread:(id)sender
{
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
[inputStream open];
}
- (void)closeThread
{
[inputStream close];
[inputStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
[inputStream release];
inputStream = nil;
}
尝试连接输入流时调用:
[self performSelector:@selector(scheduleInThread:) onThread:[[self class] networkThread] withObject:nil waitUntilDone:YES];
非常感谢任何建议。
答案 0 :(得分:1)
混合静态变量和实例变量的方式令人困惑。你愿意那样做吗?如果将其放在NSOperation中,然后使用NSOperationQueue运行它,我认为您将获得更加整洁的封装。该操作将管理自己的异步线程,因此您不必这样做。另外,我强烈建议您使用ARC。
一些注意事项:
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
@interface AsyncStreamOperation : NSOperation
@end
NS_ASSUME_NONNULL_END
#import "AsyncStreamOperation.h"
@interface AsyncStreamOperation ()
@property (atomic, strong) AsyncStreamOperation *config;
@property (atomic, strong) NSInputStream *stream;
@property (atomic, assign, getter=isExecuting) BOOL executing;
@property (atomic, assign, getter=isFinished) BOOL finished;
@end
@implementation AsyncStreamOperation
@synthesize executing = _executing;
@synthesize finished = _finished;
- (instancetype)initWithStream:(NSInputStream *)stream
{
self = [super init];
if(self) {
_stream = stream;
}
return self;
}
- (BOOL)isAsynchronous
{
return YES;
}
- (BOOL)isExecuting
{
@synchronized (self) {
return _executing;
}
}
- (void)setExecuting:(BOOL)executing
{
@synchronized (self) {
[self willChangeValueForKey:@"isExecuting"];
_executing = executing;
[self didChangeValueForKey:@"isExecuting"];
}
}
- (BOOL)isFinished
{
@synchronized (self) {
return _finished;
}
}
- (void)setFinished:(BOOL)finished
{
@synchronized (self) {
[self willChangeValueForKey:@"isFinished"];
_finished = finished;
[self didChangeValueForKey:@"isFinished"];
}
}
- (void)start
{
// Get runloop
NSRunLoop *runLoop = [NSRunLoop currentRunLoop];
// Schedule stream
[self.stream scheduleInRunLoop:runLoop forMode:NSDefaultRunLoopMode];
[self.stream open];
// Loop until finished
// NOTE: If -cancel is not called, you need to add your own logic to close the stream so this loop ends and the operation completes
while(self.executing && !self.finished && !self.cancelled && self.stream.streamStatus != NSStreamStatusClosed) {
@autoreleasepool {
// Maximum speed once per second or CPU goes through the roof
[runLoop runMode:NSDefaultRunLoopMode beforeDate:[NSDate dateWithTimeIntervalSinceNow:1.0]];
}
}
self.executing = NO;
self.finished = YES;
}
- (void)cancel
{
[super cancel];
[self.stream close];
self.executing = NO;
self.finished = YES;
}
@end