imageView.center.x 赋值;错误

imageView.center.x += 1;为什么出错?

center一次赋值,.x不能这么赋值.

如:

这样是错误的做法:

player.center.x = player.center.x + 2;

正确的做法:

player.center = CGPointMake(player.center.x + 2, player.center.y);