我如何重复这个动画？

Question

我有一个 UIImageView，它在视图加载时移动。 它首先会向上 +100，然后将 a BOOL 设置为已完成。

当 BOOL 设置为完成时，它将执行另一个动画，将 UIImageView 放回其原始位置。当我的 UIImageView 然后回到原来的位置时，它应该重新开始整个事情。这种重复应该永远持续下去！我该怎么做？

这是我的代码：

[UIView animateWithDuration:0.5
     animations:^

     {
         //move up
         Person.center = CGPointMake(Person.center.x, Person.center.y +100);

     }
                     completion:^(BOOL completed)
     {
         if (completed)
         {
             //completed move up..now move down
             [UIView animateWithDuration:0.5
                              animations:^
              {
                  Person.center = CGPointMake(Person.center.x, Person.center.y -100);
              }

              ];
         }
     }];

Answer 1

试试这个代码...

-(void)repeatForever
{
[UIView animateWithDuration:0.5
                 animations:^

 {
     //move up
     Person.center = CGPointMake(Person.center.x, Person.center.y +100);

 }
                 completion:^(BOOL completed)
 {
     if (completed)
     {
         //completed move up..now move down
         [UIView animateWithDuration:0.5 animations:^{

             Person.center = CGPointMake(Person.center.x, Person.center.y -100);

         } completion:^(BOOL finished) {
             [self repeatForever];
         }];
     }
 }];

}