WMPageController-HoverMenu是WMPageController的一个扩展，在此基础上实现了悬停菜单
我的实现是直接使用了第三方分页菜单控制器WMPageController。使用过WMPageController的童鞋可以往下看，没使用过得也可以去试一下，个人感觉比较好用，如下图：
这一部分可以直接使用WMPageController来集成，我们只需要在外面套一层UIScrollView即可。
#import "ArtScrollView.h"
@implementation ArtScrollView
//返回YES，则可以多个手势一起触发方法，返回NO则为互斥（比如外层UIScrollView名为mainScroll内嵌的UIScrollView名为subScroll，当我们拖动subScroll时，mainScroll是不会响应手势的（多个手势默认是互斥的），
//当下面这个代理返回YES时，subScroll和mainScroll就能同时响应手势，同时滚动，这符合我们这里的需求）
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
@end
该ArtScrollView用在MainViewController中，解决UIScrollView嵌套的手势冲突问题。
#import "ViewController.h"
#import "WMPageController.h"
#import "ArtScrollView.h"
#import "ChildTableViewController.h"
@interface ViewController ()<UIScrollViewDelegate>
@property (nonatomic, strong) WMPageController *pageController;
@property (nonatomic, strong) ArtScrollView *containerScrollView;
@property (nonatomic, strong) UIView *bannerView;
@property (nonatomic, strong) UIView *contentView;
@property (nonatomic, assign) BOOL isTopIsCanNotMoveTabView;
@property (nonatomic, assign) BOOL isTopIsCanNotMoveTabViewPre;
@property (nonatomic, assign) BOOL canScroll;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.title = @"标题";
_canScroll = YES;
self.automaticallyAdjustsScrollViewInsets = NO;
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(acceptMsg:) name:kHomeLeaveTopNotification object:nil];
[self setupView];
}
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
self.navigationController.navigationBar.alpha = 0;
}
- (void)setupView {
[self.view addSubview:self.containerScrollView];
[self.containerScrollView mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.leading.bottom.trailing.equalTo(self.view).offset(0);
}];
[self.containerScrollView addSubview:self.bannerView];
[self.bannerView mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.leading.trailing.equalTo(self.containerScrollView);
make.width.equalTo(self.containerScrollView);
make.height.mas_equalTo(200);
}];
[self.containerScrollView addSubview:self.contentView];
[self.contentView mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(self.bannerView.mas_bottom);
make.leading.trailing.bottom.equalTo(self.containerScrollView);
make.width.equalTo(self.containerScrollView);
make.height.mas_equalTo(kScreenHeight-64);
}];
[self.contentView addSubview:self.pageController.view];
self.pageController.viewFrame = CGRectMake(0, 0, kScreenWidth, kScreenHeight-64);
}
#pragma mark - getter
- (ArtScrollView *)containerScrollView {
if (!_containerScrollView) {
_containerScrollView = [[ArtScrollView alloc] init];
_containerScrollView.delegate = self;
_containerScrollView.showsVerticalScrollIndicator = NO;
}
return _containerScrollView;
}
- (UIView *)bannerView {
if (!_bannerView) {
_bannerView = [[UIView alloc] init];
_bannerView.backgroundColor = [UIColor blueColor];
}
return _bannerView;
}
- (UIView *)contentView {
if (!_contentView) {
_contentView = [[UIView alloc] init];
_contentView.backgroundColor = [UIColor yellowColor];
}
return _contentView;
}
- (WMPageController *)pageController {
if (!_pageController) {
_pageController = [[WMPageController alloc] initWithViewControllerClasses:@[[ChildTableViewController class],[ChildTableViewController class],[ChildTableViewController class]] andTheirTitles:@[@"tab1",@"tab2",@"tab3"]];
_pageController.menuViewStyle = WMMenuViewStyleLine;
_pageController.menuHeight = 44;
_pageController.progressWidth = 20;
_pageController.titleSizeNormal = 15;
_pageController.titleSizeSelected = 15;
_pageController.titleColorNormal = [UIColor grayColor];
_pageController.titleColorSelected = [UIColor blueColor];
}
return _pageController;
}
#pragma mark - notification
-(void)acceptMsg:(NSNotification *)notification{
NSDictionary *userInfo = notification.userInfo;
NSString *canScroll = userInfo[@"canScroll"];
if ([canScroll isEqualToString:@"1"]) {
_canScroll = YES;
}
}
#pragma mark - UIScrollViewDelegate
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
CGFloat maxOffsetY = 136;
CGFloat offsetY = scrollView.contentOffset.y;
self.navigationController.navigationBar.alpha = offsetY/136;
if (offsetY>=maxOffsetY) {
scrollView.contentOffset = CGPointMake(0, maxOffsetY);
//NSLog(@"滑动到顶端");
[[NSNotificationCenter defaultCenter] postNotificationName:kHomeGoTopNotification object:nil userInfo:@{@"canScroll":@"1"}];
_canScroll = NO;
}else{
//NSLog(@"离开顶端");
if (!_canScroll) {
scrollView.contentOffset = CGPointMake(0, maxOffsetY);
}
}
}
// 移除通知
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
#####3、为WMPageController创建子控制器。
#import "ChildTableViewController.h"
@interface ChildTableViewController ()<UIScrollViewDelegate>
@property (nonatomic, assign) BOOL canScroll;
@end
@implementation ChildTableViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"cellid"];
// add notification
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(acceptMsg:) name:kHomeGoTopNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(acceptMsg:) name:kHomeLeaveTopNotification object:nil];//其中一个TAB离开顶部的时候，如果其他几个偏移量不为0的时候，要把他们都置为0
}
#pragma mark - notification
-(void)acceptMsg:(NSNotification *)notification{
NSString *notificationName = notification.name;
if ([notificationName isEqualToString:kHomeGoTopNotification]) {
NSDictionary *userInfo = notification.userInfo;
NSString *canScroll = userInfo[@"canScroll"];
if ([canScroll isEqualToString:@"1"]) {
self.canScroll = YES;
self.tableView.showsVerticalScrollIndicator = YES;
}
}else if([notificationName isEqualToString:kHomeLeaveTopNotification]){
self.tableView.contentOffset = CGPointZero;
self.canScroll = NO;
self.tableView.showsVerticalScrollIndicator = NO;
}
}
#pragma mark - UIScrollViewDelegate
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
if (!self.canScroll) {
[scrollView setContentOffset:CGPointZero];
}
CGFloat offsetY = scrollView.contentOffset.y;
if (offsetY<0) {
[[NSNotificationCenter defaultCenter] postNotificationName:kHomeLeaveTopNotification object:nil userInfo:@{@"canScroll":@"1"}];
}
}
#pragma mark - Table view data source
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 20;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cellid" forIndexPath:indexPath];
cell.textLabel.text = [NSString stringWithFormat:@"第%ld行",indexPath.row];
return cell;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
// 移除通知
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
这个方案结合了比较流行的WMPageController实现了悬停菜单的功能，并且使用了通知方式来解耦MainViewController和WMPageController的子控制器，相当于对WMPageController的扩展吧。
这里面有一个WMPageController的坑，开始本来想的是把WMPageController的view通过约束添加到MainViewController中来，作为MainViewController的子控制器，结果不起作用，原因是WMPageController内部默认将WMPageController视图的frame设置成了相对window，不过可以通过设置WMPageController的viewFrame来设置frame。
难点主要还是对手势的理解和掌握，还有UIScrollVeiw代理的使用。
对iOS手势基本知识还不太理解的可以参考这篇文字iOS UIGestureRecognizer (手势的基本知识介绍)