Gesture operations in iPhone development: swipes

-( Void ) Touchesbegan :( nsset *) touches withevent :( uievent *) Event {
Uitouch * Touch = [touches anyobject];
Gesturestartpoint = [Touch locationinview: Self. View];
}

-( Void ) Touchesmoved :( nsset *) touches withevent :( uievent *) Event {
Uitouch * Touch = [touches anyobject];
Cgpoint currentposition = [Touch locationinview: Self. View];

Cgfloat deltax = fabsf (gesturestartpoint. X-currentposition. X );
Cgfloat deltay = fabsf (gesturestartpoint. Y-currentposition. y );

 If (Deltax> = kminimumgesturelength & deltay <= kmaximumvariance ){
Label. Text = @"  Horizontal swipe Detected  " ;
[Self defined mselector: @ selector (erasetext)
Withobject: Nil afterdelay: 2 ];
} Else   If (Deltay> = kminimumgesturelength &&
Deltax <= kmaximumvariance ){
Label. Text = @"  Vertical swipe Detected  " ;
[Self defined mselector: @ selector (erasetext) withobject: Nil
Afterdelay: 2 ];
}
}

You can also use automatic Gesture Recognition :(Uigesturerecognizer)

-(Void) Viewdidload
{
[Super viewdidload];

Uiswipegesturerecognizer * vertical = [uiswipegesturerecognizer alloc]
Initwithtarget: Self action: @ selector (reportverticalswipe :)];
Vertical. Direction = uiswipegesturerecognizerdirectionup |
Uiswipegesturerecognizerdirectiondown;
[Self. View addgesturerecognizer: vertical];

Uiswipegesturerecognizer * horizontal = [uiswipegesturerecognizer alloc]
Initwithtarget: Self action: @ selector (reporthorizontalswipe :)];
Horizontal. Direction = uiswipegesturerecognizerdireleft left |
Uiswipegesturerecognizerdirectionright;
[Self. View addgesturerecognizer: horizontal];
}
 

Then add two custom response methods:

-(Void) Reporthorizontalswipe :( uigesturerecognizer *) recognizer {
Label. Text =@"Horizontal swipe Detected";
[Self defined mselector: @ selector (erasetext) withobject: Nil afterdelay:2];
}

-(Void) Reportverticalswipe :( uigesturerecognizer *) recognizer {
Label. Text =@"Vertical swipe Detected";
[Self defined mselector: @ selector (erasetext) withobject: Nil afterdelay:2];
}
 

OK!

The above is only a single light sweep action, the following is the situation where multiple light sweep actions are performed simultaneously:

Add a loop in viewdidload:

-(Void ) Viewdidload
{
[Super viewdidload];

 For (Nsuinteger touchcount = 1 ; Touchcount <= 5 ; Touchcount ++ ){
Uiswipegesturerecognizer * vertical;
Vertical = [[uiswipegesturerecognizer alloc] initwithtarget: Self
Action: @ selector (reportverticalswipe :)];
Vertical. Direction = uiswipegesturerecognizerdirectionup |
Uiswipegesturerecognizerdirectiondown;
Vertical. numberoftouchesrequired = touchcount;
[Self. View addgesturerecognizer: vertical];

Uiswipegesturerecognizer * horizontal;
Horizontal = [[uiswipegesturerecognizer alloc] initwithtarget: Self
Action: @ selector (reporthorizontalswipe :)];
Horizontal. Direction = uiswipegesturerecognizerdireleft left |
Uiswipegesturerecognizerdirectionright;
Horizontal. numberoftouchesrequired = touchcount;
[Self. View addgesturerecognizer: horizontal];
}
}

Modify the Response Action function:

-(Void ) Reporthorizontalswipe :( uigesturerecognizer *) recognizer {
Label. Text = [nsstring stringwithformat: @"  % @ Horizontal swipe Detected  " ,
[Self descriptionfortouchcount: [recognizer numberoftouches];
[Self defined mselector: @ selector (erasetext) withobject: Nil afterdelay: 2 ];
}

-( Void ) Reportverticalswipe :( uigesturerecognizer *) recognizer {
Label. Text = [nsstring stringwithformat:@"  % @ Vertical swipe Detected  " ,
[Self descriptionfortouchcount: [recognizer numberoftouches];
[Self defined mselector: @ selector (erasetext) withobject: Nil afterdelay: 2 ];
}

-(Nsstring *) descriptionfortouchcount :( nsuinteger) touchcount {
 Switch (Touchcount ){
 Case   2 :
 Return   @" Double  " ;
 Case   3 :
 Return   @"  Triple  " ;
 Case   4 :
 Return   @"  Quadruple  " ;
 Case  5 :
 Return   @"  Quintuple  " ;
 Default :
 Return   @"" ;
}
}