ios - How can a child ignore a UIGesture in certain circumstances and let the superview handle it? -

i'm implementing similar ios's memory manager. uicollectionview uicollectionviewcell children. if swipe horizontally on cell, parent pans left. however, if swipe vertically, cells move finger.

in uicollectionviewcell subclass, have:

- (id)initwithframe:(cgrect)frame {     if (self = [super initwithframe:frame]) {                 uipangesturerecognizer* pan = [[uipangesturerecognizer alloc] initwithtarget:self action:@selector(didpan:)];         pan.maximumnumberoftouches = 1;         pan.minimumnumberoftouches = 1;         [self addgesturerecognizer:pan];     }     return self; } 

unfortunately, child cells handling pan gestures. parent never gets handle them.

- (void)didpan:(uipangesturerecognizer *)gesture {     cgpoint velocity = [gesture velocityinview:self.superview];     if (abs(velocity.y) > abs(velocity.x)) {         // move cell finger     } else {         // let parent uicollectionview pan horizontally     } } 

i know how move cell finger, don't know how other case: making child cell ignore pan gesture , letting parent handle it.

you need have cell's pan gesture recognizer recognize simultaneously collection view's pan gesture recognizer.

there few ways this, 1 way making cell delegate of pan gesture recognizer , implementing method:

- (bool)gesturerecognizer:(uigesturerecognizer *)gesturerecognizer shouldrecognizesimultaneouslywithgesturerecognizer:(uigesturerecognizer *)othergesturerecognizer {     // either return yes allow cell's gesture recognizer     // work simultaneously other recognizers:     return yes;      // or can decide whether cell's pan gesture recognizer should     // recognize simultaneously othergesturerecognizer. example,     // reference collection view's pangesturerecognizer     // , return yes if othergesturerecognizer equal recognizer:     return othergesturerecognizer == <your collection view's gesture recognizer>; }