UIScrollview使用

改变内容偏移

- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated; // animate at constant velocity to new offset

显示contentsize中的某部分

- (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated; // scroll so rect is just visible (nearest edges). nothing if rect completely visible

注意:

1. 使用 - (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated 时, 需要注意,

在uiscrollview的委托中只有, 以下这个方法可以阻止减速, 并且更改内容偏移, 一就是setContentOffset这个方法

- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView;

2. viewForZoomingInScrollView: 需要设置

minimumZoomScale

maximumZoomScale 才能够调用

uiscrollview缩放图片至少实现一下两个代理, 但能让缩放过程更加自然

//实现图片在缩放过程中居中

//scrollView正在缩放

- (void)scrollViewDidZoom:(UIScrollView *)scrollView

{

    CGFloat offsetX = (scrollView.bounds.size.width > scrollView.contentSize.width)?(scrollView.bounds.size.width - scrollView.contentSize.width)/ : 0.0;

    CGFloat offsetY = (scrollView.bounds.size.height > scrollView.contentSize.height)?(scrollView.bounds.size.height - scrollView.contentSize.height)/ : 0.0;

    UIView *v = [scrollView.subviews objectAtIndex:];

    v.center = CGPointMake(scrollView.contentSize.width/ + offsetX,scrollView.contentSize.height/ + offsetY);

}

#pragma mark - UIScrollViewDelegate

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView

{

    return _imageView;

}

巴特西

UIScrollview使用

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