iOS中scrollview自动滚动的实现

2013-01-15 01:54:04 6.6k 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

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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;

}