在项目中 很多时候我们需要 真的某个界面中的导航栏进行隐藏处理，比如饿了么的首页 导航栏默认隐藏 往上滚动 导航栏即显示
如下 效果：
我这个的做法是 首先把导航栏 隐藏掉 然后 自定义 一个导航栏 自定义导航栏默认透明度为零 然后根据 tableVIew 滚动时间 进行透明度改变：
#pragma mark --- 初始化导航栏
- (void)initNavigationView{
self.nav = [[UIView alloc] initWithFrame:CGRectMake(0, 0, kMainScreenOfWidth, 64)];
self.nav.backgroundColor = [UIColor whiteColor];
self.nav.alpha=0;
[self.viewaddSubview:self.nav];
self.searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(10, 20,kMainScreenOfWidth - 80, 44)];
self.searchBar.placeholder = @"输入商家,商品名称";
UITextField* searchField = [self.searchBarvalueForKey:@"searchField"];
if(searchField){
[searchFieldsetBackgroundColor:[UIColorcolorWithHexRGB:@"EAEAEA"]];
searchField.layer.cornerRadius=18;//设置圆角具体根据实际情况来设置
searchField.layer.masksToBounds=YES;
}
for(inti = 0;i <_searchBar.subviews.count;i++){
UIView* backView =_searchBar.subviews[i];
if([backViewisKindOfClass:NSClassFromString(@"UISearchBarBackground")] ==YES) {
[backViewremoveFromSuperview];
[_searchBar setBackgroundColor:[UIColor clearColor]];
break;
}else{
NSArray* arr =_searchBar.subviews[i].subviews;
for(intj =0;j
UIView* barView = arr[i];
if([barViewisKindOfClass:NSClassFromString(@"UISearchBarBackground")] ==YES) {
[barViewremoveFromSuperview];
[_searchBar setBackgroundColor:[UIColor clearColor]];
break;
}
}
}
}
[self.nav addSubview:self.searchBar];
UIButton* signBtn = [[UIButtonalloc]initWithFrame:CGRectMake(self.nav.gq_width-44-10,self.searchBar.gq_top,44,44)];
[signBtnsetTitle:@"sign"forState:0];
[signBtnsetTitleColor:[UIColor blackColor] forState:0];
[self.navaddSubview:signBtn];
UIButton* messageBtn = [[UIButtonalloc]initWithFrame:CGRectMake(signBtn.gq_left-10-44, signBtn.gq_top,44,44)];
[messageBtnsetTitle:@"mess"forState:0];
[messageBtnsetTitleColor:[UIColor blackColor] forState:0];
[self.navaddSubview:messageBtn];
self.searchBar.gq_width = messageBtn.gq_left -10;
}
这里是改变 自定义导航栏 透明度 根据滚动距离 设置透明度：
#pragma mark - scrollview
- (void)scrollViewDidScroll:(UIScrollView*)scrollView {
NSLog(@"%f", scrollView.contentOffset.y);
CGFloatoffset = scrollView.contentOffset.y;
CGFloatalpha = offset *1/136.0; // (200 - 64) / 136.0f
if(alpha >=1) {
alpha =1;
}
self.nav.alpha= alpha;
}
顺便给大家 奉上Demo 地址：https://github.com/junyunuo/HideNavigation.git
就上面两个步骤 就已经实现了 导航栏 渐变的效果了 有任何问题 请咨询我：805092132@qq.com
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