UIScrollView的基本属性

UIScrollView 常用属性 和 方法

常用属性

滚动内容属性

/// 内容偏移位置@property(nonatomic)         CGPoint                      contentOffset;                  // default CGPointZero/// 内容大小，设置了才可以滚动@property(nonatomic)         CGSize                       contentSize;                    // default CGSizeZero/// 内容间距@property(nonatomic)         UIEdgeInsets                 contentInset;

委托属性

@property(nullable,nonatomic,weak) id<UIScrollViewDelegate>        delegate;

要想监听滚动视图的滚动 / 拖拽 / 缩放 ／ 状态栏交互

• 需要设置 delegate
• 实现相关协议方法

弹簧效果属性

/// 允许弹簧效果@property(nonatomic)         BOOL                         bounces;                        // default YES. if YES, bounces past edge of content and back again/// 始终允许垂直弹@property(nonatomic)         BOOL                         alwaysBounceVertical;           // default NO. if YES and bounces is YES, even if content is smaller than bounds, allow drag vertically/// 始终允许水平弹@property(nonatomic)         BOOL                         alwaysBounceHorizontal;

分页属性

/// 允许分页@property(nonatomic,getter=isPagingEnabled) BOOL          pagingEnabled __TVOS_PROHIBITED;// default NO. if YES, stop on multiples of view bounds

指示器属性

/// 显示水平指示器@property(nonatomic)         BOOL                         showsHorizontalScrollIndicator; // default YES. show indicator while we are tracking. fades out after tracking/// 显示垂直指示器@property(nonatomic)         BOOL                         showsVerticalScrollIndicator;   // default YES. show indicator while we are tracking. fades out after tracking/// 指示器间距@property(nonatomic)         UIEdgeInsets                 scrollIndicatorInsets;          // default is UIEdgeInsetsZero. adjust indicators inside of insets/// 指示器样式@property(nonatomic)         UIScrollViewIndicatorStyle   indicatorStyle;                 // default is UIScrollViewIndicatorStyleDefault

在 scrollView 中指示器本质上就是 UIImageView

通过查看视图层次结构可以看到

缩放属性

/// 最小缩放比例@property(nonatomic) CGFloat minimumZoomScale;     // default is 1.0/// 最大缩放比例@property(nonatomic) CGFloat maximumZoomScale;     // default is 1.0. must be > minimum zoom scale to enable zooming

要允许缩放

• 必须设置以上两个属性
• 同时遵守协议
• 实现协议方法 -viewForZoomingInScrollView:

状态栏属性

/// 点击状态栏滚动到顶部@property(nonatomic) BOOL  scrollsToTop __TVOS_PROHIBITED;          // default is YES.

一个视图中，如果有多个 scrollView

只有唯一一个 scrollView 的 scrollsToTop 属性设置为 YES，才支持点击状态栏滚动到顶部

键盘属性

/// 键盘解除模式@property(nonatomic) UIScrollViewKeyboardDismissMode keyboardDismissMode NS_AVAILABLE_IOS(7_0); // default is UIScrollViewKeyboardDismissModeNone

如果是 UITextView，通常需要将 alwaysBounceVertical 属性设置为 YES

typedef NS_ENUM(NSInteger, UIScrollViewKeyboardDismissMode) {    // 无    UIScrollViewKeyboardDismissModeNone,    // 拖拽关闭键盘    UIScrollViewKeyboardDismissModeOnDrag,      // dismisses the keyboard when a drag begins    // 必须要拖拽到键盘才可以关闭键盘，很少使用    UIScrollViewKeyboardDismissModeInteractive, // the keyboard follows the dragging touch off screen, and may be pulled upward again to cancel the dismiss} NS_ENUM_AVAILABLE_IOS(7_0);

常用方法

/// 动画设置偏移位置- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated;  // animate at constant velocity to new offset/// 动画设置滚动区域- (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated;         // scroll so rect is just visible (nearest edges). nothing if rect completely visible