ios - 未在不同线程上调用委托(delegate)

Question

我正在尝试使用 CoreBluetooth 框架，并且我创建了一个辅助类 (btHelper) 来使代码更易于维护等。

问题在于，在这个帮助类中，当所有内容都被混入大类时，委托(delegate)方法不再像最初那样被调用。是的，我已经在助手类的 .h 中设置了委托(delegate)方法，是的，我已经将对象 CBCentralManager 委托(delegate)设置为 self。我几乎完成了所有事情，就像在一节课上做的一样。我相信它与主线程有关，但我在这方面的经验很少。

具体来说，我要调用的委托(delegate)方法是

-(void)centralManagerDidUpdateState:(CBCentralManager *)central 

任何人都可以告诉我我必须做什么才能让委托(delegate)调用在这个帮助程序类中正常工作吗？谢谢!

下面是PrimaryViewController类和btHelper类

btHelper.m

-(void) activateBluetooth
{
self.manager= [[CBCentralManager alloc] initWithDelegate:self queue:nil];
}

- (void)centralManagerDidUpdateState:(CBCentralManager *)central
{
  //DELEGATE METHOD THAT NEVER GETS CALLED. SHOULD BE CALLED AS SOON AS self.manager is initiated
   self.isAvailable=FALSE;
   switch (central.state) {
    case CBCentralManagerStatePoweredOff:
        NSLog(@"CoreBluetooth BLE hardware is powered off");
        break;
    case CBCentralManagerStatePoweredOn:
        NSLog(@"CoreBluetooth BLE hardware is powered on and ready");
         self.isAvailable=TRUE;
        break;
    case CBCentralManagerStateResetting:
        NSLog(@"CoreBluetooth BLE hardware is resetting");
        break;
    case CBCentralManagerStateUnauthorized:
        NSLog(@"CoreBluetooth BLE state is unauthorized");
        break;
    case CBCentralManagerStateUnknown:
        NSLog(@"CoreBluetooth BLE state is unknown");
        break;
    case CBCentralManagerStateUnsupported:
        NSLog(@"CoreBluetooth BLE hardware is unsupported on this platform");
        break;
    default:
        break;
}

}

PrimaryViewController.m

-(IBAction)connect
{  
  btHelper *bluetoothManager= [[btHelper alloc]init];
  [bluetoothManager activateBluetooth];

}

Answer 1

您的助手实例是 -connect 方法中的局部变量。所以 ARC 在您可以接收委托(delegate)方法之前释放它(和 CBCentralManager 实例)。让您的助手成为 PrimaryViewController 的实例变量(或属性)，这将解决您的问题。

@interface PrimaryViewController : UIViewController
{
    // BTHelper instead of btHelper, to follow naming convention
    BTHelper *_bluetoothManager;
}
@end

@implementation PrimaryViewController
    -(IBAction)connect
    {
      // FIXME: this don't check if _bluetoothManager is already instantiated
      _bluetoothManager = [[BTHelper alloc] init];
      [_bluetoothManager activateBluetooth];
    }
@end