源码地址IBActionSheet
最初接触到IBActionSheet是因为用UIActionSheet的时候，项目组有人说会导致内存泄露，在delegate那里，查了一下文档
weak 声明，肯定不会引起内存泄露啦。ios8以后已经不赞成使用UIActionSheet了，话说回来，IBActionSheet 是可以自己定制的UIActionSheet，类似ios7风格，而且按钮类型可以自己定制！ 系统的添加标题方式如下：
<pre><code>- (NSInteger)addButtonWithTitle:(NSString *)title;
- (NSString *)buttonTitleAtIndex:(NSInteger)buttonIndex;
</code></pre>
IBActionSheet的就丰富多了
<pre><code>- (NSInteger)addButtonWithTitle:(NSString *)title;
- (void)dismissWithClickedButtonIndex:(NSInteger)buttonIndex animated:(BOOL)animated;
- (id)initWithTitle:(NSString *)title delegate:(id<IBActionSheetDelegate>)delegate cancelButtonTitle:(NSString *)cancelTitle destructiveButtonTitle:(NSString *)destructiveTitle otherButtonTitles:(NSString *)otherTitles, ... NS_REQUIRES_NIL_TERMINATION;
- (id)initWithTitle:(NSString *)title callback:(IBActionCallback)callback cancelButtonTitle:(NSString *)cancelTitle destructiveButtonTitle:(NSString *)destructiveTitle otherButtonTitles:(NSString *)otherTitles, ... NS_REQUIRES_NIL_TERMINATION;
- (id)initWithTitle:(NSString *)title delegate:(id<IBActionSheetDelegate>)delegate cancelButtonTitle:(NSString *)cancelTitle destructiveButtonTitle:(NSString *)destructiveTitle otherButtonTitlesArray:(NSArray *)otherTitlesArray;
- (id)initWithTitle:(NSString *)title callback:(IBActionCallback)callback cancelButtonTitle:(NSString *)cancelTitle destructiveButtonTitle:(NSString *)destructiveTitle otherButtonTitlesArray:(NSArray *)otherTitlesArray;
- (NSInteger)numberOfButtons;
- (NSString *)buttonTitleAtIndex:(NSInteger)index;
- (void)rotateToCurrentOrientation;
// fonts - (void)setFont:(UIFont *)font;
- (void)setTitleFont:(UIFont *)font;
- (void)setFont:(UIFont *)font forButtonAtIndex:(NSInteger)index;
</code></pre>
还有其他添加的方式，主要是支持block,大爱呀！
源码分析：点击黑色半透明区域消失：
<pre><code>UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(cancelSelection)];
tap.numberOfTapsRequired = 1;
[self.transparentView addGestureRecognizer:tap];</code></pre>
先判断回调函数有木有处理，然后删除，因为删除有动画过程所以单独处理了一下
<pre><code>- (void) cancelSelection {
if(self.callback) self.callback(self, NSIntegerMax);
[self removeFromView];
}
</code></pre>
<pre><code>removeFromView</code></pre>处理消失的过程！
这里因为兼容了ios7以前的版本！所以使用<pre><code>#define SYSTEM_VERSION_LESS_THAN(version) ([[[UIDevice currentDevice] systemVersion] compare:version options:NSNumericSearch] == NSOrderedAscending)
</code></pre>判断了一下。为了使用ios7才有的动画函数：<pre><code>+ (void)animateWithDuration:(NSTimeInterval)duration delay:(NSTimeInterval)delay usingSpringWithDamping:(CGFloat)dampingRatio initialSpringVelocity:(CGFloat)velocity options:(UIViewAnimationOptions)options animations:(void (^)(void))animations completion:(void (^)(BOOL finished))completion NS_AVAILABLE_IOS(7_0);
</code></pre>增加了阻尼系数，弹性系数，让动画看起来更加真实，逼真！
还有一点比较有趣的函数：
- (void)setMaskTo:(UIView*)view byRoundingCorners:(UIRectCorner)corners
{
UIBezierPath *rounded = [UIBezierPath bezierPathWithRoundedRect:view.bounds
byRoundingCorners:corners
cornerRadii:CGSizeMake(4.0, 4.0)];
CAShapeLayer *shape = [[CAShapeLayer alloc] init];
[shape setPath:rounded.CGPath];
view.layer.mask = shape;
}
通常的方法设置圆角，会导致四个边角都会有圆角，如果只要设置一个方向的圆角，可以考虑这种方法。好饿，今天源码读到这里暂时！
