IOS Touch and gestures

Touch

Responder Object

Not all objects in iOS can handle events, and only objects that inherit Uiresponder can receive and handle events. We call it "Responder object".

Uiapplication,uiviewcontroller,uiview are inherited from Uiresponder, so they are all responder objects that are capable of receiving and handling events.

UIView?????? Three situations where touch time is not accepted??????????????????

• • ???? User interaction is not accepted???????????? userinteractionenable = NO;?? (Example: Uilabel and Uiimageview???? These controls userinteractionenable default to?????? No so these controls are not accepted by default for touch events)

• • ?? Hide:?? Hidden=yes;

• • Transparent:???? alpha=0.0~0.01

  ???? The way to respond to touch can be achieved by uiresponder the following four methods

  -(void) Touchesbegan: (Nsset *) touches withevent: (Uievent *) event;????????????????

  This method is triggered when the user starts to touch

  -(void) touchesmoved: (Nsset *) touches withevent: (Uievent *) event;???????????????????? This method is triggered when the user's finger starts to move

  -(void) touchesended: (Nsset *) touches withevent: (Uievent *) event;?????????? This method is triggered when the user touches the end

  -(void) touchescancelled: (Nsset *) touches withevent: (uievent*) event;?????????????????????????????? Fires this method when a system event (such as insufficient memory, incoming calls) terminates a touch event

  This method is triggered when the user starts to touch-(void) Touchesbegan: (Nsset<uitouch *> *) touches withevent: (Nullable uievent *) event{Nsarray *to        Ucharr = [touches allobjects];//gets the number of fingers when the user starts to touch uitouch *touch = [Toucharr objectatindex:0]; Cgpoint point = [touch Locationinview:[touch view]; Gets the position of the finger at the beginning of the touch//NSLog (@ "%d", touch.tapcount);//Gets the number of clicks of the finger in a short time if (Touch.tapcount = = 1) {[Self perform        Selector: @selector (Tapone) Withobject:nil afterdelay:0.5]; Delay 0.5 seconds call method Tapone} if (Touch.tapcount = = 2) {//If the user wants to simply respond to a double-click, destroy the deferred call [NSObject Cancelpreviousp    Erformrequestswithtarget:self selector: @selector (Tapone) Object:nil]; }}-(void) tapone{NSLog (@ "click once");} This method is triggered when the user's finger starts to move-(void) touchesmoved: (Nsset<uitouch *> *) touches withevent: (Nullable uievent *) event{NSLog (@ " Finger movement ");} This method is triggered when the user touches the end-(void) touchesended: (Nsset<uitouch *> *) touches withevent: (Nullable uievent *) event{NSLog (@ " Touch gesture End ");} Fires the method when a system event (such as insufficient memory, incoming calls) terminates a touch event-(void)Touchescancelled: (Nullable nsset<uitouch *> *) touches withevent: (Nullable uievent *) event{} 

  
  gestures

  UITapGestureRecognizer Click

  label = [[UILabel alloc]initwithframe:cgrectmake (self.view.bounds.size.width/2-50, self.view.bounds.size.height/ 2-50, (+)];    Label.backgroundcolor = [Uicolor greencolor];    label.userinteractionenabled = YES;    [Self.view Addsubview:label];        UITapGestureRecognizer *tapgesture = [[UITapGestureRecognizer alloc]initwithtarget:self Action: @selector ( Tapgesturehandle:)];    tapgesture.numberoftapsrequired = 1; Number of clicks required    tapgesture.numberoftouchesrequired = 1;//requires 1 fingers to click    [Label Addgesturerecognizer:tapgesture];

  
  

  -(void) Tapgesturehandle: (UITapGestureRecognizer *) gesture{    NSLog (@ "click Trigger");    Cgpoint point = [gesture LocationInView:self.view]; Get click coordinates//}

  
  

  Uipinchgesturerecognizer kneading

     Uipinchgesturerecognizer *pinchgesture = [[Uipinchgesturerecognizer alloc]initwithtarget:self Action: @selector ( Pinchgesturehandle:)];    label.multipletouchenabled = YES; Allow multi-touch support    [Label Addgesturerecognizer:pinchgesture];    

  
  

  -(void) Pinchgesturehandle: (Uipinchgesturerecognizer *) gesture{    cgfloat scale = Gesture.scale;//get user pinch ratio    CGFloat velocity = gesture.velocity;  Get user pinch speed    label.transform = Cgaffinetransformscale (label.transform, scale, scale);    Gesture.scale = 1.0;    }

  
  

  Uipangesturerecognizer Drag and drop

     Uipangesturerecognizer *pangesture = [[Uipangesturerecognizer alloc]initwithtarget:self Action: @selector ( Pangesturehandle:)];    Pangesture.maximumnumberoftouches = 1; Allow the pack processor to support up to a few fingers drag    pangesture.minimumnumberoftouches = 1;//allows the pack-up processor to support a minimum of several finger drag    [Label Addgesturerecognizer:pangesture];

  
  

  -(void) Pangesturehandle: (Uipangesturerecognizer *) gesture{    cgpoint point = [gesture Translationinview:label];// Get control Displacement    label.transform = Cgaffinetransformtranslate (Label.transform, Point.x, point.y);    [Gesture settranslation:cgpointmake (0, 0) Inview:label];    }

  
  

  Uiswipegesturerecognizer Swipe

  Because a control nail once swipe gesture only supports swiping in one direction, if you need a swipe gesture in four directions, you need to add four times

  for (int i = 0; i < 4; i + +) {        Uiswipegesturerecognizer *swipgesture = [[Uiswipegesturerecognizer Alloc]initwithtar Get:self Action: @selector (Swipgesturehandle:)];        swipgesture.numberoftouchesrequired = 1;        Swipgesture.direction = 1 << i;        [Label addgesturerecognizer:swipgesture];    }

  
  

  -(void) Swipgesturehandle: (Uiswipegesturerecognizer *) gesture{    if (gesture.direction = = Uiswipegesturerecognizerdirectionright) {        NSLog (@ "swipe right");    }    if (gesture.direction = = uiswipegesturerecognizerdirectionleft) {        NSLog (@ "swipe left");    }    if (gesture.direction = = Uiswipegesturerecognizerdirectiondown) {        NSLog (@ "swipe down");    }    if (gesture.direction = = uiswipegesturerecognizerdirectionup) {        NSLog (@ "swipe up");}    }

  
  

  Uilongpressgesturerecognizer Long Press

      Uilongpressgesturerecognizer *longpress=[[uilongpressgesturerecognizer alloc]initwithtarget:self Action: @selector (handlelongpress:)];    Longpress.minimumpressduration=1;  At least how many seconds to press will trigger gesture    longpress.allowablemovement=1;  The maximum distance allowed for a finger to move    longpress.numberoftouchesrequired=1;//allows the user to trigger the gesture with several fingers        [_viewtext addgesturerecognizer: Longpress];

  to display a custom menu item by using a long press gesture
  

      UIMenuItem *transmitem = [[UIMenuItem alloc]initwithtitle:@ ' forward ' action: @selector (Transmitem:)];    UIMenuItem *deleteitem = [[uimenuitem alloc]initwithtitle:@ ' delete ' action: @selector (DeleteItem:)];    UIMenuItem *reportitem = [[UIMenuItem alloc]initwithtitle:@ "Report" Action: @selector (ReportItem:)];

  
  

  -(void) Handlelongpress: (Uilongpressgesturerecognizer *) gesture{    if (gesture.state = = Uigesturerecognizerstatebegan) {        NSLog (@ "long press gesture");        [Self becomefirstresponder];        Uimenucontroller *menu=[uimenucontroller Sharedmenucontroller];        [Email protected] [Transmitem,deleteitem,reportitem];        CGRect Rect=cgrectmake (Ten, ten, +);        [Menu Settargetrect:rect inview:_viewtext];        [Menu Setmenuvisible:yes Animated:yes];    }    } -(BOOL) canbecomefirstresponder{    return YES; -(BOOL) Canperformaction: (SEL) Action Withsender: (ID) sender{    if (action = = @selector (transmitem:) | | Action = = @selector (deleteItem:) | | Action = = @selector (reportitem:))    {return YES;} else{        return NO;}}

  -(void) Transmitem: (ID) sender{    NSLog (@ "forwarding");} -(void) DeleteItem: (ID) sender{    NSLog (@ "delete");} -(void) ReportItem: (ID) sender{    NSLog (@ "forwarding");}

if the control supports two gestures at a time, you need to import

#import <UIKit/UIGestureRecognizerSubclass.h>

also, rewrite two methods

Whether to block another gesture-(BOOL) Canbepreventedbygesturerecognizer: (Uigesturerecognizer *) geature{    return NO;} -(BOOL) Canpreventgesturerecognizer: (Uigesturerecognizer *) preventedgesturerecognizer{    return NO;

IOS Touch and gestures