iOS中scrollview自动滚动的实现

最新推荐文章于 2022-04-29 23:07:26 发布

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最新推荐文章于 2022-04-29 23:07:26 发布

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分类专栏： scrollView 文章标签： ios开发

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本博客详细介绍了在iOS应用中如何实现scrollview的自动滚动，包括使用setContentOffset:animated:方法设置滚动位置，利用viewDidLoad和viewDidAppear生命周期方法进行开场动画效果，以及通过timer实现更平滑的滚动动画。

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iOS中scrollview自动滚动的实现

.h文件

[plain]

@interface Interface1 : UIViewController{

IBOutlet UIScrollView*scroller;

IBOutlet UILabel *warnung;

}

@property (nonatomic, retain) IBOutletUIScrollView* scrollView;

.m文件

[plain]

- (void)viewDidAppear:(BOOL)animated

{

[super viewDidAppear:animated];

CGPoint bottomOffset =CGPointMake(self.scrollView.contentOffset.x, self.scrollView.contentSize.height- self.scrollView.bounds.size.height);

[self.scrollViewsetContentOffset:bottomOffset animated:NO];

CGPoint newOffset = self.scrollView.contentOffset;

newOffset.y = 0;

[self.scrollViewsetContentOffset:newOffset animated:YES];

}

- (void)viewDidLoad

{

[scrollersetScrollEnabled:YES];

[scrollersetContentSize:CGSizeMake(320, 420)];

[superviewDidLoad];

}

使用setContentOffset:animated:

[plain]

UIScrollView *scrollView = ...;

CGPoint newOffset = scrollView.contentOffset;

newOffset.y = 0;

[scrollViewsetContentOffset:newOffset animated:YES];

如果需要开场动画的效果，在scrollView的viewcontroller实现

[plain]

- (void)viewDidLoad

{

[super viewDidLoad];

// ...

CGPoint bottomOffset =CGPointMake(self.scrollView.contentOffset.x, self.scrollView.contentSize.height- self.scrollView.bounds.size.height);

[self.scrollViewsetContentOffset:bottomOffset animated:NO];

}

- (void)viewDidAppear:(BOOL)animated

{

[superviewDidAppear:animated];

CGPoint newOffset = self.scrollView.contentOffset;

newOffset.y = 0;

[self.scrollViewsetContentOffset:newOffset animated:YES];

}

移动的慢点，用timer实现：

[plain]

- (void)viewDidLoad

{

[super viewDidLoad];

// ...

CGPoint bottomOffset =CGPointMake(self.scrollView.contentOffset.x, self.scrollView.contentSize.height- self.scrollView.bounds.size.height);

[self.scrollViewsetContentOffset:bottomOffset animated:NO];

}

- (void)viewDidAppear:(BOOL)animated

{

[superviewDidAppear:animated];

CGPoint bottomOffset =CGPointMake(self.scrollView.contentOffset.x, self.scrollView.contentSize.height- self.scrollView.bounds.size.height);

//设置延迟时间

float scrollDurationInSeconds= 4.0;

//计算timer间隔

float totalScrollAmount =bottomOffset.y;

float timerInterval =scrollDurationInSeconds / totalScrollAmount;

[NSTimerscheduledTimerWithTimeInterval:timerInterval target:selfselector:@selector(scrollScrollView:) userInfo:nil repeats:YES];

}

- (void)scrollScrollView:(NSTimer *)timer

{

CGPointnewScrollViewContentOffset = self.scrollView.contentOffset;

//向上移动 1px

newScrollViewContentOffset.y-= 1;

newScrollViewContentOffset.y= MAX(0, newScrollViewContentOffset.y);

//如果到顶了，timer中止

if (newScrollViewContentOffset.y== 0) {

[timerinvalidate];

}

//最后设置scollView's contentOffset

self.scrollView.contentOffset= newScrollViewContentOffset;

}