+ (void)transitionFromView:(UIView *)fromViewtoView:(UIView *)toViewduration:(NSTimeInterval)duration options:(UIViewAnimationOptions)options completion:(void(^)(BOOLfinished))completion;
参数说明:
–duration:动画的持续时间
–options:转场动画的类型
–animations:将改变视图属性的代码放在这个block中
–completion:动画结束后,会自动调用这个block