iOS中scrollview自动滚动的实现

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;  

}