我正在开发一个使用蓝牙 2.1 的应用程序。每次应用程序激活时,它都会打开一个 EASession。每次应用程序进入后台或终止时,EASession 都会关闭。
如果蓝牙模块已连接,并且应用程序重新启动,则可以正常打开,发送/获取数据一切正常。
但是,如果蓝牙模块在应用程序运行时失去通信,则在重新连接并从后台打开应用程序后。EASession 打开失败。
并且没有列出连接的配件。
- (EAAccessory *)selectedAccessory
{
if (_selectedAccessory == nil)
{
_accessoryList = [[NSMutableArray alloc] initWithArray:[[EAAccessoryManager sharedAccessoryManager] connectedAccessories]];
NSLog(@"accessory count: %d", [_accessoryList count]);
if ([_accessoryList count])
{
_selectedAccessory = [_accessoryList objectAtIndex:0];
NSArray *protocolStrings = [_selectedAccessory protocolStrings];
self.protocolString = [protocolStrings objectAtIndex:0];
}else{
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Alert" message:@"You don't have any machine connected.\nPlease go to Settings->Bluetooth to set up connection." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];
[alert show];
}
}
return _selectedAccessory;
}
这里 [_accessoryList 计数] 为 0。
有谁知道发生了什么?谢谢!
编辑:
我进行了更多测试,这次看起来不同。
- (BOOL)openSession
{
if (_session == nil)
{
NSLog(@"EAController::openSession");
[_selectedAccessory setDelegate:self];
_session = [[EASession alloc] initWithAccessory:[self selectedAccessory] forProtocol:_protocolString];
if (_session)
{
[[_session inputStream] setDelegate:self];
[[_session inputStream] scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[[_session inputStream] open];
[[_session outputStream] setDelegate:self];
[[_session outputStream] scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[[_session outputStream] open];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setBool:YES forKey:Unit_Has_Connection];
NSLog(@"opened the session");
}
else
{
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setBool:NO forKey:Unit_Has_Connection];
NSLog(@"creating session failed");
}
}
return (_session != nil);
}
这次 selectedAccessory 看起来不错。但它不能初始化会话。
在 initWithAccessory 行之后,它会打印出 ERROR:
2013-06-17 15:03:39.967 IceMachine[770:60b] ERROR - opening session failed
2013-06-17 15:03:39.968 IceMachine[770:60b] ERROR - /SourceCache/ExternalAccessory/ExternalAccessory-237/EASession.m:-[EASession dealloc] - 139 unable to close session for _accessory=0x15543fe0 and sessionID=65536