iOS仿今日头条滑动导航

之前写了篇博客网易首页导航封装类、 网易首页导航封装类优化 ,今天在前两个的基础上仿下今日头条。

1.网易首页导航封装类中主要解决了上面导航的ScrollView和下面的页面的ScrollView联动的问题,以及上面导航栏的便宜量。

2. 网易首页导航封装类优化 中主要解决iOS7以上滑动返回功能中UIScreenEdgePanGestureRecognizer与ScrollView的滑动的手势冲突问题。

今天仿今日头条滑动导航和 网易首页导航封装类优化 相似,这个也是解决手势冲突,UIPanGestureRecognizer与ScrollView的手势冲突。

一、ViewController的层次

用上面的图来介绍,左侧的个人页面ViewController上面通过addChildViewController添加了一个以MainViewController为RootViewController的

UINavigationController,通过addSubview将UINavigationController的View添加到个人页面ViewController的View上。

二、仿今日头条滑动导航主要有3个问题:

1.UIPanGestureRecognizer与ScrollView的手势冲突

为了达到拖动滑动的效果，需要给MainViewController添加一个UIPanGestureRecognizer,由于底部是ScrollView和TableView组成的，所以会使UIPanGestureRecognizer与底部的冲突,和 网易首页导航封装类优化 类似需要在

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer中根据gestureRecognizer返回YES来使ScrolView和UIPanGestureRecognizer都识别。

2.UIPanGestureRecognizer滑动结束的位置不正确

用UIPanGestureRecognizer滑动根据便宜量来改变UINavigationController的View的位置,在今日头条中滑动结束时UINavigationController的View要么在原位要么在右侧，不会停在中间,这个问题让我想起了之前做的果冻效果,手势有状态state,根据手势的状态来改变UINavigationController的View的位置,特别是在手势结束时。

3.由于1使ScrolView和UIPanGestureRecognizer都识别,导致返回时ScrolView也会滑动

让底部的ScrolView能滑动的时间应该是UINavigationController的View在初始位置frame的x为0，所以在它的frame的x>0时,底部的bottomScrollView的

scrollEnabled=NO。

三、 主要实现代码(导航的代码就不贴了,只贴主要的)

1.声明一个拖动手势

@property(nonatomic,strong) UIPanGestureRecognizer *panGestureRecognizer;

2.为MainViewController添加手势

 _panGestureRecognizer=[[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panGesture:)];      _panGestureRecognizer.delegate=self;      [self.navigationController.view addGestureRecognizer:_panGestureRecognizer];

3.手势识别的方法

//平移  -(void)panGesture:(UIPanGestureRecognizer*)pan  {      //在View中的位置  //    CGPoint point=[pan locationInView:self.navigationController.view];      //在View中的移动量 以手指按下的为原点      CGPoint point1=[pan translationInView:self.navigationController.view];      if (pan.state==UIGestureRecognizerStateChanged&&pan==_panGestureRecognizer) {                    if (point1.x>0&&self.navigationController.view.frame.origin.x<self.navigationController.view.frame.size.width-100) {              float x= self.navigationController.view.frame.origin.x+point1.x>self.navigationController.view.frame.size.width-100?self.navigationController.view.frame.size.width-100:self.navigationController.view.frame.origin.x+point1.x;              self.navigationController.view.frame=CGRectMake(x, self.navigationController.view.frame.origin.y, self.navigationController.view.frame.size.width, self.navigationController.view.frame.size.height);              NSLog(@"%@",NSStringFromCGRect(self.navigationController.view.frame));          }          else if(point1.x<0)          {              NSLog(@"aaa  %f",self.navigationController.view.frame.origin.x);              float x=self.navigationController.view.frame.origin.x+point1.x<0?0:self.navigationController.view.frame.origin.x+point1.x;              self.navigationController.view.frame=CGRectMake(x, self.navigationController.view.frame.origin.y, self.navigationController.view.frame.size.width, self.navigationController.view.frame.size.height);          }      }      else if(pan.state==UIGestureRecognizerStateEnded)      {            if (self.navigationController.view.frame.origin.x>self.navigationController.view.frame.size.width/3) {              [UIView animateWithDuration:0.2 animations:^{                  self.navigationController.view.frame=CGRectMake(self.navigationController.view.frame.size.width-100, 0, self.navigationController.view.frame.size.width, self.navigationController.view.frame.size.height);              } completion:^(BOOL finished) {                   self.bottomScrollView.scrollEnabled=YES;              }];          }          else          {              [UIView animateWithDuration:0.2 animations:^{                  self.navigationController.view.frame=CGRectMake(0, 0, self.navigationController.view.frame.size.width, self.navigationController.view.frame.size.height);              } completion:^(BOOL finished) {                  self.bottomScrollView.scrollEnabled=YES;              }];                        }      }      //偏移量是增加的应该设为0      [pan setTranslation:CGPointZero inView:self.navigationController.view];  }

4.手势冲突解决

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer  {      if (self.bottomScrollView.contentOffset.x<=0.0&&gestureRecognizer==_panGestureRecognizer) {          if (self.navigationController.view.frame.origin.x>0) {             self.bottomScrollView.scrollEnabled=NO;          }          else          {              self.bottomScrollView.scrollEnabled=YES;            }          return YES;      }      return NO;  }

四、效果图