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
@interface Interface1 : UIViewController { IBOutlet UIScrollView *scroller; IBOutlet UILabel *warnung; } @property (nonatomic, retain) IBOutlet UIScrollView* scrollView;
.m文件
- (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:
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
- (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:
- (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; }