Question

如果我调用CFUserNotificationDisplayAlert（）来显示警告框，它会在控制台中输出以下消息：

CFUserNotificationDisplayAlert:  called from main application thread, will block waiting for a response.

我不希望打印此邮件。有没有办法禁用它？或者，有更好的方法来解决这个问题吗？谢谢！

Answer 1

CFUserNotificationDisplayAlert（）是一个便捷函数，它总是在等待用户输入时阻塞主线程。如果你不想阻止主线程，你必须自己创建CFUserNotification并将它附加到主线程的runloop：

// First, add member variables in your class to store the user notification and runloop source, like this.  You'll need to be able to access these variables later, from your callback method:
CFUserNotificationRef _userNotification;
CFRunLoopSourceRef _runLoopSource;

// When you want to show the alert, you will create it, create a runloop source for it, then attach the runloop source to the runloop:
_userNotification= CFUserNotificationCreate(... set this up the way you want to ...);
_runLoopSource = CFUserNotificationCreateRunLoopSource(NULL, userNotification, YourUserNotificationCallback, 0);
CFRunLoopAddSource(CFRunLoopGetMain(), runLoopSource, kCFRunLoopCommonModes);

// ...elsewhere, you'll need to define your callback function, something like this:
void YourUserNotificationCallback(CFUserNotificationRef userNotification, CFOptionFlags responseFlags)
{
    // Handle the user's input here.
    ...

    // Release your notification and runloop source:
    CFRunLoopRemoveSource(CFRunLoopGetMain(), _runLoopSource, kCFRunLoopCommonModes);
    CFRelease(_runLoopSource);
    CFRelease(_userNotification);
}

如何抑制CFUserNotificationDisplayAlert生成的控制台消息

1 个答案: