问题
Anyone know how to detect the "delete" key using UIKeyCommand
on iOS 7?
回答1:
As people were having problems with Swift, I figured a small, complete example in both Objective C and Swift might be a good answer.
Note that Swift doesn't have a \b
escape character for backspace, so you need to use a simple Unicode scalar value escape sequence of \u{8}
. This maps to the same old-school ASCII control character number 8 ("control-H", or ^H in caret notation) for backspace as \b
does in Objective C.
Here's an Objective C view controller implementation that catches backspaces:
#import "ViewController.h"
@implementation ViewController
// The View Controller must be able to become a first responder to register
// key presses.
- (BOOL)canBecomeFirstResponder {
return YES;
}
- (NSArray *)keyCommands {
return @[
[UIKeyCommand keyCommandWithInput:@"\b" modifierFlags:0 action:@selector(backspacePressed)]
];
}
- (void)backspacePressed {
NSLog(@"Backspace key was pressed");
}
@end
And here's the equivalent view controller in Swift:
import UIKit
class ViewController: UIViewController {
override var canBecomeFirstResponder: Bool {
return true;
}
override var keyCommands: [UIKeyCommand]? {
return [
UIKeyCommand(input: "\u{8}", modifierFlags: [], action: #selector(backspacePressed))
]
}
@objc func backspacePressed() {
NSLog("Backspace key was pressed")
}
}
回答2:
Simple really - need to look for the backspace character "\b"
回答3:
You can always try UIKeyInput. https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UIKeyInput_Protocol/index.html#//apple_ref/occ/intfm/UIKeyInput/deleteBackward
The function should be
- (void)deleteBackward
来源:https://stackoverflow.com/questions/22068308/detect-delete-key-using-uikeycommand