How to save the value of the field(field type is "true_false") immedately in ACF?

Here is my situation:
1.I have set a field called "cat" which its field type is "select" and the field option taxonomy is category in ACF.

2.I have three post category in my site:"boy","girl" and "teacher".

3.I have set a field called "te" which its field type is "text",and I set its conditional-logic is:Only when the "cat" field's value is "boy" did the "te" field show.

4.When I edit post,the "te" field will show or hide immediately after I change the value of "cat" field.

5.However,it's useless for other "select" field type such as "radio"?"checkbox"?"true_false" and so on.
I wrote the code in function.php like this:

if( get_field("is_tw") ) //"is_tw" is a kind of "true_false" field type.
		echo "succeed";

However,when I choose "is_tw",it print nothing.Only I click "save draft" did the screen print "succeed".
I can't see the result immediately after I chooes.

6.Is there any way to solve this problem?Thank you very much!