使用RAC滑動單元格

我正在構建一個向該單元格添加平移手勢的可滑動單元格。基本上，它具有與郵箱應用程序中的單元格相同的外觀和感覺，您可以在其中有一個頂部視圖，您可以向左或向右滑動以顯示下方的另一個視圖（revealView）。使用RAC滑動單元格

我想與反應的方法來建立這個，所以我做的方法是：

首先，當我設置視圖和平移手勢，我過濾rac_gestureSignal得到手勢的當前狀態並使用綁定更新頂視圖位置（這裏簡化一些實現細節）以及當手勢結束/取消時隱藏/顯示揭示視圖。我還呼籲setNeedsLayout當任panDirection或revealView變化（以相應地更新revealView幀）從它們的值合併的信號，以及去除揭示視圖對細胞複用：

- (void)setupView 
{ 
    UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:nil]; 
    panGesture.delegate = self; 

    RACSignal *gestureSignal = [panGesture rac_gestureSignal], 
       *beganOrChangeSignal = [gestureSignal filter:^BOOL(UIGestureRecognizer *gesture) { 
     return gesture.state == UIGestureRecognizerStateChanged || gesture.state == UIGestureRecognizerStateBegan; 
    }], 
       *endOrCancelSignal = [gestureSignal filter:^BOOL(UIGestureRecognizer *gesture) { 
     return gesture.state == UIGestureRecognizerStateEnded || gesture.state == UIGestureRecognizerStateCancelled; 
    }]; 

    RAC(self, contentSnapshotView.center) = [beganOrChangedSignal map:^id(id value) { 
     return [NSValue valueWithCGPoint:[self centerPointForTranslation:[panGesture translationInView:self]]]; 
    }]; 

    [beganOrChangeSignal subscribeNext:^(UIPanGestureRecognizer *panGesture) { 
     [self updateTopViewFrame]; 

     [panGesture setTranslation:CGPointZero inView:self]; 
    }]; 

    [[endOrCancelSignal filter:^BOOL(UIPanGestureRecognizer *gestureRecognizer) { 
     return [self shouldShowRevealView]; 
    }] subscribeNext:^(id x) { 
     [self showRevealViewAnimated:YES]; 
    }]; 

    [[endOrCancelSignal filter:^BOOL(UIPanGestureRecognizer *gestureRecognizer) { 
     return [self shouldHideRevealView]; 
    }] subscribeNext:^(id x) { 
     [self hideRevealViewAnimated:YES]; 
    }]; 

    [[RACSignal merge:@[RACObserve(self, panDirection), RACObserve(self, revealView)]] subscribeNext:^(id x) { 
     [self setNeedsLayout]; 
    }]; 

    [[self rac_prepareForReuseSignal] subscribeNext:^(id x) { 
     [self.revealView removeFromSuperview]; 
     self.revealView = nil; 
    }]; 

    [self addGestureRecognizer:panGesture]; 
}

然後，我暴露一個信號屬性（revealViewSignal），當揭示視圖顯示/隱藏時它將發送YES/NO值。因此，您可以訂閱此信號，從而在視圖改變其狀態時採取行動。在內部，這個信號將是一個RACSubject發送下一個事件的每個顯示/隱藏動畫結束後：

- (void)showRevealViewAnimated:(BOOL)animated 
{ 
    [UIView animateWithDuration:animated ? 0.1 : 0.0 
        animations:^{ 
         // SHOW ANIMATIONS 
        } 
        completion:^(BOOL finished) { 
         [(RACSubject *)self.revealViewSignal sendNext:@(YES)]; 
        }]; 
} 

- (void)hideRevealViewAnimated:(BOOL)animated 
{ 
    [UIView animateWithDuration:animated ? 0.1 : 0.0 
        animations:^{ 
         // HIDE ANIMATIONS 
        } 
        completion:^(BOOL finished) { 
         [(RACSubject *)self.revealViewSignal sendNext:@(NO)]; 
        }]; 
}

一切正常，但我只是想知道，如果這是建立這種說法正確的做法以RAC方式。此外，還有兩種手勢識別器委託方法，我希望在上面的相同設置方法中進行設置，但我無法弄清楚是否可以使用rac_signalForSelector：fromProtocol：方法，因此我最終實現了它們一如既往：

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer 
{ 
    return [self checkIfGestureShouldBegin:gestureRecognizer]; 
} 

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer 
{ 
    return [self checkIfGestureShouldRecognize:gestureRecognizer]; 
}

任何幫助將高度appreaciated，謝謝！

來源

2014-03-04 Joan Romano