iOS中scrollview自动滚动的实现
http://bbs.csdn.net/topics/390347330
原问题是，我要展现给用户的内容放在scrollview中，让内容从上到底自动滚动，我最开始用的是DDAutoscrollview，但是无法实现。
一种解决方案见下边，更多解决方案见：http://ask.csdn.net/questions/374
.h文件
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@interface Interface1 : UIViewController { IBOutlet UIScrollView *scroller; IBOutlet UILabel *warnung;}@property (nonatomic, retain) IBOutlet UIScrollView* scrollView; |
.m文件
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- (void)viewDidAppear:(BOOL)animated{ [super viewDidAppear:animated]; CGPoint bottomOffset = CGPointMake(self.scrollView.contentOffset.x, self.scrollView.contentSize.height - self.scrollView.bounds.size.height); [self.scrollView setContentOffset:bottomOffset animated:NO]; CGPoint newOffset = self.scrollView.contentOffset; newOffset.y = 0; [self.scrollView setContentOffset:newOffset animated:YES];}- (void)viewDidLoad{ [scroller setScrollEnabled:YES]; [scroller setContentSize:CGSizeMake(320, 420)]; [super viewDidLoad];} |
使用setContentOffset:animated:
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UIScrollView *scrollView = ...;CGPoint newOffset = scrollView.contentOffset;newOffset.y = 0;[scrollView setContentOffset:newOffset animated:YES]; |
如果需要开场动画的效果，在scrollView的viewcontroller实现
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- (void)viewDidLoad{ [super viewDidLoad]; // ... CGPoint bottomOffset = CGPointMake(self.scrollView.contentOffset.x, self.scrollView.contentSize.height - self.scrollView.bounds.size.height); [self.scrollView setContentOffset:bottomOffset animated:NO];}- (void)viewDidAppear:(BOOL)animated{ [super viewDidAppear:animated]; CGPoint newOffset = self.scrollView.contentOffset; newOffset.y = 0; [self.scrollView setContentOffset:newOffset animated:YES];} |
移动的慢点，用timer实现：
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- (void)viewDidLoad{ [super viewDidLoad]; // ... CGPoint bottomOffset = CGPointMake(self.scrollView.contentOffset.x, self.scrollView.contentSize.height - self.scrollView.bounds.size.height); [self.scrollView setContentOffset:bottomOffset animated:NO];}- (void)viewDidAppear:(BOOL)animated{ [super viewDidAppear: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; [NSTimer scheduledTimerWithTimeInterval:timerInterval target:self selector:@selector(scrollScrollView:) userInfo:nil repeats:YES];}- (void)scrollScrollView:(NSTimer *)timer{ CGPoint newScrollViewContentOffset = 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) { [timer invalidate]; } //最后设置scollView's contentOffset self.scrollView.contentOffset = newScrollViewContentOffset;} |
