scrollView常用属性

• contentSize: 内容大小，设置了才可以滚动
• contentOffset: 内容偏移位置
• contentInset: 内容间距
• pagingEnabled: 是否允许分页
• bounces: 是否允许弹簧效果
• showsHorizontalScrollIndicator: 是否允许显示水平指示器(滚动条)
• showsVerticalScrollIndicator: 是否允许显示垂直指示器(滚动条)

---

• 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