YISwipeShiftCaret 介绍
Swipe-to-shift text input caret for iOS (no private APIs)
示例代码：
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// add swipe-shift-caret gestures to all of UITextField/UITextView
[YISwipeShiftCaret install];
//
// or, you can implement gestures manually as follows, adding to non-textInput (wider parent) view:
//
// YISwipeShiftCaretGestureRecognizer* gesture = [[YISwipeShiftCaretGestureRecognizer alloc] initWithTextInput:self.textField];
// [self.window addGestureRecognizer:gesture];
return YES;
}