objective-c

问题 My view controllers need to send messages to a couple of model objects. How do I obtain references to these model objects inside the view controller? These model objects are "singletons" (in that there should only be one copy of them in the system at once) and they are used by multiple view controllers. So I can't instantiate them in the init method of each view controller. I can't use constructor injection as the runtime chooses the init method that gets used to create the view controller. I

问题 My view controllers need to send messages to a couple of model objects. How do I obtain references to these model objects inside the view controller? These model objects are "singletons" (in that there should only be one copy of them in the system at once) and they are used by multiple view controllers. So I can't instantiate them in the init method of each view controller. I can't use constructor injection as the runtime chooses the init method that gets used to create the view controller. I

问题 My view controllers need to send messages to a couple of model objects. How do I obtain references to these model objects inside the view controller? These model objects are "singletons" (in that there should only be one copy of them in the system at once) and they are used by multiple view controllers. So I can't instantiate them in the init method of each view controller. I can't use constructor injection as the runtime chooses the init method that gets used to create the view controller. I

问题 My view controllers need to send messages to a couple of model objects. How do I obtain references to these model objects inside the view controller? These model objects are "singletons" (in that there should only be one copy of them in the system at once) and they are used by multiple view controllers. So I can't instantiate them in the init method of each view controller. I can't use constructor injection as the runtime chooses the init method that gets used to create the view controller. I

问题 I am banging my head. I am implementing push notification. Everything is working fine (push is received, badge is updated) but under iOS 13.3 the method application(_:didReceiveRemoteNotification:fetchCompletionHandler:) is not called when the app is in the background. If the app is in the foreground or using an iOS 12 device the method is called. I register for push notification in the following way: [[UNUserNotificationCenter currentNotificationCenter] requestAuthorizationWithOptions:

问题 I am working on Camera Application user are taking a picture its fine,but i want to crop anywhere in that image and send it to server. How can I do this? 回答1: Check out this link for details: http://www.hive05.com/2008/11/crop-an-image-using-the-iphone-sdk/ Basic code: - (UIImage*)imageByCropping:(UIImage *)imageToCrop toRect:(CGRect)rect { //create a context to do our clipping in UIGraphicsBeginImageContext(rect.size); CGContextRef currentContext = UIGraphicsGetCurrentContext(); //create a

问题 I am working on Camera Application user are taking a picture its fine,but i want to crop anywhere in that image and send it to server. How can I do this? 回答1: Check out this link for details: http://www.hive05.com/2008/11/crop-an-image-using-the-iphone-sdk/ Basic code: - (UIImage*)imageByCropping:(UIImage *)imageToCrop toRect:(CGRect)rect { //create a context to do our clipping in UIGraphicsBeginImageContext(rect.size); CGContextRef currentContext = UIGraphicsGetCurrentContext(); //create a

问题 The title is a bit confusing...I'll explain I have an NSMutableArray I am populating with NSMutableDictionary objects. What I am trying to do is before the dictionary object is added to the array, I need to check whether any of the dictionaries contain a value equal to an id that is already set. Example: Step 1: A button is clicked setting the id of an object for use in establishing a view. Step 2: Another button is pressed inside said view to save some of its contents into a dictionary, then

问题 I'm trying to create a simple transition animation between two view controllers, both of which have the same label. I simply want to animate the label from its position in the first view controller, to its position in the second (see below illustration). I have set up my view controllers to use a custom animation controller, where I have access to both view controllers and the label through an outlet. In the animation block, I simply set the frame of the label on the first view controller to

问题 So I have peripheral BLE device and I need some identifier for it to later share with another iPhone. Example I connect with iPhone 'A' to peripheral. iPhone 'A' saves peripheral's identifier to database and later I easily can take iPhone 'B' and connect to the peripheral found by this identifier. Now there is UUID what changes for every iPhone-peripheral connection, but MAC Address is not available. What could you suggest? 回答1: If you do not manufacture the peripheral yourself then you can