之前在平台给大家分享了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

以上所述是小编给大家分享的IOS仿今日头条滑动导航栏，希望对大家有所帮助。