iOS中scrollview自動滾動的實現 – iPhone手機開發技術文章 iPhone軟體開發教學課程

.h文件

[plain]  

 @interface Interface1 : UIViewController {  

  

    IBOutlet UIScrollView *scroller;  

    IBOutlet UILabel *warnung;  

  

}  

  

  

@property (nonatomic, retain) IBOutlet UIScrollView* 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.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:

[plain]  

UIScrollView *scrollView = …;  

CGPoint newOffset = scrollView.contentOffset;  

newOffset.y = 0;  

[scrollView setContentOffset:newOffset animated:YES];  

 

如果需要開場動畫的效果,在scrollView的viewcontroller實現

[plain]  

– (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];  

}  

 

移動的慢點,用timer實現:

[plain]  

– (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);  

  

    //設置延遲時間  

    float scrollDurationInSeconds = 4.0;  

  

    //計算timer間隔  

  

  

    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;  

  

    //向上移動 1px  

    newScrollViewContentOffset.y -= 1;  

  

  

    newScrollViewContentOffset.y = MAX(0, newScrollViewContentOffset.y);  

  

    //如果到頂瞭,timer中止  

    if (newScrollViewContentOffset.y == 0) {  

        [timer invalidate];  

    }  

  

    //最後設置scollView's contentOffset  

    self.scrollView.contentOffset = newScrollViewContentOffset;  

}  

 

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