之前在本站平台給大家分享了網易首頁導航封裝類、網易首頁導航封裝類優化,今天在前兩個的基礎上仿下今日頭條。

1.網易首頁導航封裝類中主要解決了上面導航的ScrollView和下面的頁面的ScrollView聯動的問題,以及上面導航欄的便宜量。

2.網易首頁導航封裝類優化中主要解決iOS7以上滑動返回功能中UIScreenEdgePanGestureRecognizer與ScrollView的滑動的手勢沖突問題。

今天仿今日頭條滑動導航和網易首頁導航封裝類優化相似,這個也是解決手勢沖突,UIPanGestureRecognizer與ScrollView的手勢沖突。

一、ViewController的層次

用上面的圖來介紹,左側的個人頁面ViewController上面通過addChildViewController添加了一個以MainViewController為RootViewController的

UINavigationController,通過addSubview將UINavigationController的View添加到個人頁面ViewController的View上。

二、仿今日頭條滑動導航主要有3個問題:

1.UIPanGestureRecognizer與ScrollView的手勢沖突

為了達到拖動滑動的效果，需要給MainViewController添加一個UIPanGestureRecognizer,由於底部是ScrollView和TableView組成的，所以會使UIPanGestureRecognizer與底部的沖突,和網易首頁導航封裝類優化類似需要在

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer中根據gestureRecognizer返回YES來使ScrolView和UIPanGestureRecognizer都識別。

2.UIPanGestureRecognizer滑動結束的位置不正確

用UIPanGestureRecognizer滑動根據便宜量來改變UINavigationController的View的位置,在今日頭條中滑動結束時UINavigationController的View要麼在原位要麼在右側，不會停在中間,這個問題讓我想起了之前做的果凍效果,手勢有狀態state,根據手勢的狀態來改變UINavigationController的View的位置,特別是在手勢結束時。

3.由於1使ScrolView和UIPanGestureRecognizer都識別,導致返回時ScrolView也會滑動

讓底部的ScrolView能滑動的時間應該是UINavigationController的View在初始位置frame的x為0，所以在它的frame的x>0時,底部的bottomScrollView的scrollEnabled=NO。

三、 主要實現代碼(導航的代碼就不貼了,只貼主要的)

1.聲明一個拖動手勢

@property(nonatomic,strong) UIPanGestureRecognizer *panGestureRecognizer;

2.為MainViewController添加手勢

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

3.手勢識別的方法

//平移
-(void)panGesture:(UIPanGestureRecognizer*)pan
{
//在View中的位置
// CGPoint point=[pan locationInView:self.navigationController.view];
//在View中的移動量 以手指按下的為原點
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;
}];
}
}
//偏移量是增加的應該設為0
[pan setTranslation:CGPointZero inView:self.navigationController.view];
}

4.手勢沖突解決

- (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、效果圖

以上所述是小編給大家分享的IOS仿今日頭條滑動導航欄，希望對大家有所幫助。