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;
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.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];
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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;
} |