uikit

问题 There's the option to go the long way, if an receiver class conforms to the NSKeyValueProtocol: [myInstance setValue:[NSNumber numberWithInt:2] forKey:@"integerProperty"]; or the short way: myInstance.integerProperty = 2; what's the point of this KVC method? When is this useful? 回答1: First, those aren't the same, the second should be: myInstance.integerProperty = [NSNumber numbwerWithInt:2]; if integerProperty is an NSNumber . In general you use the second form when you are doing the most

问题 I find that in iOS 8 using UITextView sizeThatFits: causes glitchy scrolling behavior. The Text View is constantly scrolling away from the line you are typing on. It seems to be scrolling to the top of the view and then back again. If it matters, the view is set as an inputAccessoryView. Via the keyboard I'll type: 1 return 2 return 3 return 4 The TextView the moment before I type 4 : In the delegate method I call sizeThatFits: . - (void)textViewDidChange:(UITextView *)textView { [textView

问题 I find that in iOS 8 using UITextView sizeThatFits: causes glitchy scrolling behavior. The Text View is constantly scrolling away from the line you are typing on. It seems to be scrolling to the top of the view and then back again. If it matters, the view is set as an inputAccessoryView. Via the keyboard I'll type: 1 return 2 return 3 return 4 The TextView the moment before I type 4 : In the delegate method I call sizeThatFits: . - (void)textViewDidChange:(UITextView *)textView { [textView

问题 I have set a custom tint color for a UINavigationBar (within a UINavigationController ) which, in turn, sets an appropriate matching color for the UIBarButtonItems which are inserted into the UINavigationBar . However, when I select a UIBarButtonItem the button turns into (presumably) the highlighted state and presents a different color, which looks quite a bit out and does not nicely match the tint color. Is there a way to change this highlighted state color to a custom color? Ideally, I

问题 Currently I see that a touch event will show me the UIView where the touch occured. But what if I need to detect a touch of some non rectangular shape, like a circle. How would I go about doing something like that ? Basically I want to do something only if the user touches somewhere within a circular area that's not visible. Any help/direction is appreciated, TIA! 回答1: You would do it like so. Note that 'locationInView' will return the coordinates of the touch with respect to the specified

问题 I am using SwiftUI and bridge to UITextField (I need to assign firstResponder). I use the code from here: SwiftUI: How to make TextField become first responder? The following code updates my @Binding var. This of course is intended behavior. The problem is that this causes the textField to ignore the frame/ bounds. It just expands and pushes other elements out of the view. Other parts of the view are also reliant on the @State. func textFieldDidChangeSelection(_ textField: UITextField) { text

问题 When I enable my simulator debug option "Color blended laysers" Then showing the different result as follow: Sorry that I can not post images: http://i.imgur.com/LYiPCfy.jpg?1 http://i.imgur.com/t7hArne.jpg?1 回答1: It looks like labels with Chinese characters will have an extra sublayer (not subviews). When I add two UILabel s to a view, one with English characters and one with Chinese, there are slightly different hierarchies. 0x7fd3b972c020 is the UILabel with English characters: (lldb) po [

问题 When I enable my simulator debug option "Color blended laysers" Then showing the different result as follow: Sorry that I can not post images: http://i.imgur.com/LYiPCfy.jpg?1 http://i.imgur.com/t7hArne.jpg?1 回答1: It looks like labels with Chinese characters will have an extra sublayer (not subviews). When I add two UILabel s to a view, one with English characters and one with Chinese, there are slightly different hierarchies. 0x7fd3b972c020 is the UILabel with English characters: (lldb) po [

问题 When I enable my simulator debug option "Color blended laysers" Then showing the different result as follow: Sorry that I can not post images: http://i.imgur.com/LYiPCfy.jpg?1 http://i.imgur.com/t7hArne.jpg?1 回答1: It looks like labels with Chinese characters will have an extra sublayer (not subviews). When I add two UILabel s to a view, one with English characters and one with Chinese, there are slightly different hierarchies. 0x7fd3b972c020 is the UILabel with English characters: (lldb) po [

问题 Why doesn't UITableViewCell background color work (set in interface builder)? I note from some searching that the follow code set in your custom subclass of UITableViewController does work (see below): - (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath { cell.backgroundColor = [UIColor redColor]; } But I would still like to just understand why interface builder has a background color setting for the TableViewCell,