在希望的田野上

摘要：Notice in Figure 22.2 that each view has a layer and each view is its layer’s delegate. We’ll come back to the delegate relationship later in the chap... 阅读全文

摘要：NSValue valueWithNonretainedObjecthttp://stackoverflow.com/questions/8748736/weak-object-in-an-nsdictionaryhttp://stackoverflow.com/questions/3618479/... 阅读全文

摘要：// Create a new popover controller that will display the imagePicker imagePickerPopover = [[UIPopoverController alloc] initWithContentViewController:imagePicker]; [imagePickerPopover setDelegate:self]; // Display the popover controller; sender// is the camera bar button item[imagePickerPopover prese 阅读全文