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,以及上面导航栏的偏移量。
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4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滑动根据偏移量来改变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 scrollEnabled=NO。
4.页面拖到右边时点击右边页面可以滑到初始位置
首先时点击滑到初始页面则需要给UINavigationController的View添加轻点手势,添加后就会与tableView的手势冲突,所以有出现了一个新的bug,解决这个bug还比较好解决,因为bottomScrollView的ScrollView只有Pan、pich手势,tap手势没有，所以只要设置tap轻点手势的状态就能解决. 在UINavigationController的View的frame的x>0时，tap手势的enable＝NO，＝＝0时为Yes即可(上周未将轻点加上,这周算是补上了,下面具体实现代码我就不改了)。
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) {
//下面if主要是解决tableView滑动会引起navigationController.View也滑动的bug
if (point1.x<50&&self.navigationController.view.frame.origin.x==0) {
return;
}
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