问题

I am currently building a custom keyboard and I am almost done. One problem that I have is with the delete button. When the user taps the delete button, it does what it should do and deletes the previous text entry. However when the user holds the button down, nothing happens. How do I make it so that when the user holds down the delete button, the keyboard continuously deletes like in the standard ios keyboard? This is my current code:

pragma mark Keyboards

- (void)addGesturesToKeyboard{
[self.keyboard.deleteKey addTarget:self action:@selector(pressDeleteKey)forControlEvents:UIControlEventTouchUpInside];

and:

-(void)pressDeleteKey{
[self.textDocumentProxy deleteBackward];
}

Thanks for your help.

回答1:

Set a counter as soon as the screen is touched, such as 2-5 seconds. The situation known as Long press gesture, and here is the link to the simliar questions.

Long press gesture on UICollectionViewCell

回答2:

Swift 3 Use "allowableMovement" property

override func viewDidLoad() {
    super.viewDidLoad()

    let longPress = UILongPressGestureRecognizer(target: self, action: #selector(KeyboardViewController.handleLongPress(_:)))
    longPress.minimumPressDuration = 0.5
    longPress.numberOfTouchesRequired = 1
    longPress.allowableMovement = 0.1
    buttonDelete.addGestureRecognizer(longPress)
}

func handleLongPress(_ gestureRecognizer: UIGestureRecognizer) {
    textDocumentProxy.deleteBackward()
}

回答3:

you can do this by managing button’s events like touchdown, touchupinside and touchoutside.

When button press at that time start timer with delay of 0.2 seconds and delete last characters from textDocumentProxy until button’s touchup method will fire and after that you just need to invalidate timer.

[self.btnDelete addTarget:self action:@selector(btnTocuhDown:) forControlEvents:UIControlEventTouchDown];
[self.btnDelete addTarget:self action:@selector(btnTouchUp:) forControlEvents:UIControlEventTouchUpInside];
[self.btnDelete addTarget:self action:@selector(btnTouchUp:) forControlEvents:UIControlEventTouchUpOutside];

-(void) btnTocuhDown

    NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:0.2  target:self selector:@selector(kpTimerMethod:) userInfo:nil repeats:YES];

self.kpTimer = timer;
__weak typeof(self)weakSelf = self;
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^(void){
    if (timer == self.kpTimer) {
        [weakSelf.kpTimer fire];
    }
});

-(void)kpTimerMethod:(NSTimer *)timer

if (self.btnDelete.highlighted)
{
    [self deleteLastCharacter];
}
else
{
    [timer invalidate];
    self.kpTimer = nil;
}

-(void)deleteLastCharacter

NSString *strInput = self.textDocumentProxy.documentContextBeforeInput;

if (strInput.length > 1)
    NSString *coupleOfLastCharacters = [strInput substringWithRange:NSMakeRange(strInput.length-2, 2)];
    if( [@"yo" caseInsensitiveCompare:coupleOfLastCharacters] == NSOrderedSame ) {
        [self.textDocumentProxy deleteLastCharacter];
    }
}
[self.textDocumentProxy deleteLastCharacter];

-(void) btnTouchUp

[self.kpTimer invalidate];
self.kpTimer = nil;

回答4:

- (void)addGesturesToKeyboard{

 UILongPressGestureRecognizer *ges = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
    ges.minimumPressDuration = 0.1;
    ges.numberOfTouchesRequired = 1;
    ges.delegate = self;
    [self.mykeyboard.deleteKey addGestureRecognizer:ges];
}

- (void)longPress:(UILongPressGestureRecognizer*)gesture {


        [self.textDocumentProxy deleteBackward];
}

来源：https://stackoverflow.com/questions/25633189/ios-8-custom-keyboard-hold-button-to-delete

标签

ios