作用
切换多个vc(控制器) 的controller.其每一个单元,称为一页:page.在一个page中,可以添加一个vc, 也可以添加2个vc, 如果添加2个vc, 其展示的效果是分栏效果.
切换控制器方法, 只有调用这个方法才能切换
- (void)setViewControllers:(nullable NSArray<UIViewController *> *)viewControllers direction:(UIPageViewControllerNavigationDirection)direction animated:(BOOL)animated completion:(void (^ __nullable)(BOOL finished))completion;
案例
test.gif
逻辑
-
HomeViewController为主控制器, 添加一个UIPageViewController:pvc -
pvc添加 5个子控制器 - 5个子控制器都继承了一个控制器
YHManufacHomeVcChildVcParentVc - 5个子控制器加载数据的时机是: 为将显示的
vc设置参数时.
代码
1.设置5个子vc
- (NSArray<YHManufacHomeVcChildVcParentVc *> *)vcs{
if (!_vcs) {
//整体vc
UIStoryboard *sb = [UIStoryboard storyboardWithName:NSStringFromClass([YHWholeVc class]) bundle:nil];
YHWholeVc *wholeVc = [sb instantiateInitialViewController];
//排名vc
sb = [UIStoryboard storyboardWithName:NSStringFromClass([YHRankVc class]) bundle:nil];
YHRankVc *rankVc = [sb instantiateInitialViewController];
//区域vc
YHAreaVc *areaVc = [[YHAreaVc alloc] init];
areaVc.delegate = self;
//品类vc
YHCategoryVc *categoryVc = [[YHCategoryVc alloc] init];
categoryVc.delegate = self;
//渠道vc
YHSourceVc *srcVc = [[YHSourceVc alloc] init];
srcVc.delegate = self;
self.vcs = @[wholeVc, rankVc, areaVc, categoryVc, srcVc];
}
return _vcs;
}
2.设置 UIPageViewController,及相应的方法
- (void)setupPageViewController{
CGFloat scX = 0;
CGFloat scY = CGRectGetMaxY(self.pgView.frame);
CGFloat scW = self.view.yh_width;
CGFloat scH = self.view.yh_height - scY - CGRectGetHeight(self.tabBarController.tabBar.frame);
CGRect rect = CGRectMake(scX, scY, scW, scH);
NSDictionary *options = @{UIPageViewControllerOptionInterPageSpacingKey : @(20)};
UIPageViewController *pvc = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:options];
self.pvc = pvc;
[self.view addSubview:pvc.view];
pvc.view.frame = rect;
pvc.dataSource = self;
pvc.delegate = self;
[self moveToViewNumber:0 animated:YES];
[self reloadVcData:self.vcs[0]];
}
#pragma mark ------------------------------------------
#pragma mark private method of pvc
- (void)moveToViewNumber:(NSInteger)index animated:(BOOL)animated {
YHManufacHomeVcChildVcParentVc *vc = (YHManufacHomeVcChildVcParentVc *)self.vcs[index];
UIPageViewControllerNavigationDirection direction = UIPageViewControllerNavigationDirectionForward;
//是否与当前索引相等,不相等则滚动
if (self.currentIndex != index) {
if (self.currentIndex > index) {
direction = UIPageViewControllerNavigationDirectionReverse;
}
WeakSelf
[self.pvc setViewControllers:@[vc] direction:direction animated:animated completion:^(BOOL finished) {
[weakSelf updateCurrentIndex:weakSelf.titleBtnsView.subviews[index]];
}];
}
}
///设置选中按钮的状态,添加子vc的view
- (void)updateCurrentIndex:(UIButton *)btn{
if (self.selectedBtn == btn) {
return;
}
//背景
self.selectedBtn.selected = NO;
self.selectedBtn.backgroundColor = [UIColor lightGrayColor];
btn.selected = YES;
self.selectedBtn = btn;
self.selectedBtn.backgroundColor = YHGlobalColor;
NSInteger index = btn.tag - YHMinTagOfTitleBtn;
self.pageControl.currentPage = index;
self.currentIndex = index;
}
3. 为子vc传递参数. 子vc中有自己的处理:如果参数有变化,便会加载数据.
- (void)reloadVcData:(YHManufacHomeVcChildVcParentVc *)vc{
YHWholeDataParam *param = [YHWholeDataParam new];
param.YearMonth = self.currentDate;
param.area = [YHArchiveTool shareArchiveTool].loginM.area;
param.level = [YHArchiveTool shareArchiveTool].loginM.level;
param.isM = YHReportTypeDaily;
vc.paramOfData = param;
}
4.实现UIPageController 的数据源
#pragma mark ------------------------------------------
#pragma mark UIPageViewControllerDataSource
- (nullable UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController{
NSUInteger index = [self.vcs indexOfObject:(YHManufacHomeVcChildVcParentVc *)viewController];
if ((index == 0) || (index == NSNotFound)) {
return nil;
}
index--;
YHManufacHomeVcChildVcParentVc *vc = (YHManufacHomeVcChildVcParentVc *)self.vcs[index];
return vc;
}
- (nullable UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController{
NSUInteger index = [self.vcs indexOfObject:(YHManufacHomeVcChildVcParentVc *)viewController];;
if (index == NSNotFound) {
return nil;
}
index++;
if (index >= YHVcsCount) {
return nil;
}
YHManufacHomeVcChildVcParentVc *vc = (YHManufacHomeVcChildVcParentVc *)self.vcs[index];
return vc;
}
5.切换vc时, 使目的vc 加载数据
注: 此处不会重复加载, 如上述, 因为子vc的set方法中有判断.
#pragma mark ------------------------------------------
#pragma mark UIPageViewControllerDelegate
- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray<UIViewController *> *)pendingViewControllers{
YHManufacHomeVcChildVcParentVc *vc = (YHManufacHomeVcChildVcParentVc *)pendingViewControllers.firstObject;
NSInteger index = [self.vcs indexOfObject:vc];
[self reloadVcData:vc];
[self updateCurrentIndex:self.titleBtnsView.subviews[index]];
}
6. 在下代理方法中处理切换时的细节, 更新相应按钮的选中状态及设置 pageControl 的 currentPage.
此时要注意这种情况: 用户左右轻微切换界面, 但是并没有切换到相应的界面.
/**
* 此代理方法仅在手指drag时,才会调用.代码设置,不会调用.
*
* @param pageViewController 当前UIPageViewController
* @param finished 动画是否结束
* @param previousViewControllers 拖动开始前的vc.如果从控制器src拖动到控制器des,则为src;如果没有成功拖动到des,即拖动了一点点,又返回到src,也为src
* @param completed 是否完成拖动到控制器des,如果拖动到des,为YES;如果没有拖动到des,为NO
* 利用finished与completed参数,可控制代码执行的时机
*/
- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed{
if (completed){
}else{
YHLog(@"---no completed---%zd: %@", previousViewControllers.count, previousViewControllers.firstObject);
YHManufacHomeVcChildVcParentVc *vc = (YHManufacHomeVcChildVcParentVc *)previousViewControllers.firstObject;
NSInteger index = [self.vcs indexOfObject:vc];
[self updateCurrentIndex:self.titleBtnsView.subviews[index]];
}
}
上面代码使用了UIPageViewController的两个代理方法:
// Sent when a gesture-initiated transition begins.
- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray<UIViewController *> *)pendingViewControllers NS_AVAILABLE_IOS(6_0);
// Sent when a gesture-initiated transition ends. The 'finished' parameter indicates whether the animation finished, while the 'completed' parameter indicates whether the transition completed or bailed out (if the user let go early).
- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray<UIViewController *> *)previousViewControllers transitionCompleted:(BOOL)completed;
与UICollectionView 的比较
优点
- UIPageViewController 切换界面时, 即使从0跳到10界面, 其动画UI效果也很友好:只是一个界面的跨度; 而如果使用UICollectionView就只能
animated:NO
缺点
- 因为UIPageViewController没有将其子view为scrollView的控件暴露出来
- 不能精确地处理一些跟contentOffset的距离有关的操作.
- 或者说要实现精确操作,要做很多工作. 因为需要拿到UIPageViewController的scrollView, 然后设置其代理.
这只是我的想法,并没有实际执行.通过NSLog, 可以看到UIPageViewController的view有一个子view, 这个子view的类别是queuingScrollView, 而它继承自scrollView . - UIPageViewController在切换控制器时有bug, 有时没有切换到正确的界面.
如框架MBXPageViewController的FreeButtonsDemo中,(我是在9.2测试)第一次点击第三个按钮时,便没有正确跳转.不知作者为什么没有发现. - 出现时机:
- 滚动方式: UIPageViewControllerTransitionStyleScroll
- 滚动时
animated:YES
具体可见下链接,链接中也给出了可能的解决方法:
http://stackoverflow.com/questions/12939280/uipageviewcontroller-navigates-to-wrong-page-with-scroll-transition-style
由于我的demo并没有出现这个问题,所以暂未深入研究.
