需求 - 14 - "ShouldWillDid" - 1

<pre name="code" class="objc">- (BOOL)textViewShouldBeginEditing:(UITextView *)textView;
- (BOOL)textViewShouldEndEditing:(UITextView *)textView;

- (void)textViewDidBeginEditing:(UITextView *)textView;
- (void)textViewDidEndEditing:(UITextView *)textView;

我们常常能看到这样的Should Begin End  Will Did 状态性的一些函数方法。

这里给出一个用通知来实现的例子：

给出extern 全局 或者宏定义的一些变量定义，参照苹果原生的一些例子，如：

UIKIT_EXTERN NSString * const UITextViewTextDidBeginEditingNotification;
UIKIT_EXTERN NSString * const UITextViewTextDidChangeNotification;
UIKIT_EXTERN NSString * const UITextViewTextDidEndEditingNotification;

我们可以这样定义：

extern NSString *const KGModalWillShowNotification;
extern NSString *const KGModalDidShowNotification;
extern NSString *const KGModalWillHideNotification;
extern NSString *const KGModalDidHideNotification;

NSString *const KGModalWillShowNotification = @"KGModalWillShowNotification";
NSString *const KGModalDidShowNotification = @"KGModalDidShowNotification";
NSString *const KGModalWillHideNotification = @"KGModalWillHideNotification";
NSString *const KGModalDidHideNotification = @"KGModalDidHideNotification";

然后分别在实现这个操作前后发出通知，即可：

dispatch_async(dispatch_get_main_queue(), ^{

//Here
[[NSNotificationCenter defaultCenter] postNotificationName:KGModalWillShowNotification object:self];

[self.window makeKeyAndVisible];

if(animated){
viewController.styleView.alpha = 0;
[UIView animateWithDuration:kFadeInAnimationDuration animations:^{
viewController.styleView.alpha = 1;
}];

containerView.alpha = 0;
containerView.layer.shouldRasterize = YES;
containerView.transform = CGAffineTransformScale(CGAffineTransformIdentity, 0.4, 0.4);
[UIView animateWithDuration:kTransformPart1AnimationDuration animations:^{
containerView.alpha = 1;
containerView.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1.1, 1.1);
} completion:^(BOOL finished) {
[UIView animateWithDuration:kTransformPart2AnimationDuration delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{
containerView.alpha = 1;
containerView.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1, 1);
} completion:^(BOOL finished2) {
containerView.layer.shouldRasterize = NO;

//Here.
[[NSNotificationCenter defaultCenter] postNotificationName:KGModalDidShowNotification object:self];

}];
}];
}
});

最后是实现的操作：

- (void)willShow:(NSNotification *)notification{
NSLog(@"will show");
}

- (void)didShow:(NSNotification *)notification{
NSLog(@"did show");
}

下一节会讲解delegate怎么来实现这种状态的方法。