i liked you 是我以前喜欢你,但不一定表示现在不喜欢. 是否现在不喜欢要看语境和上下文. 如果现在不喜欢,比较准确（并无歧义）的表达是 I have liked you I did like you 而且,说者有时会补充 but/though 什么什么,比如 I have liked you,but things are different now. I did like you,but things changed. Though I no longer feel this way,I did like you. 等等.
