你需要确定谁真正有兴趣看到这个新列表。假设感兴趣的部分是某个类listusingclass的示例，这应该是可行的。

final ListUsingClass listUser = new ListUsingClass(); // or assign to existing reference
saveBtnYes.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    listUser.setActivityNames(saveBtnYesFunc(currentYesBtnId));
                 }
            });

你的问题不太清楚，我想你希望 Button 单击，则 Array ( activityNames )它被保存在某处。你可以这样做，如果我明白的话：

class YourClass {  //almost surely it extends Activity (or AppCompatActivity)

    private List<String> thePlaceWhereTheArrayWillBeLocated = new ArrayList<String>();  //You should define a class varibale where the result of saveBtnYesFunc will ends up (I think that the content is of String type)

    ... onCreate(...) {
    super.onCreate(savedInstanceState);
    ...
    ...
    saveBtnYes.setOnClickListener(new View.OnClickListener() {   //I don't know if it's inside the onCreate, but it could be here
            @Override
            public void onClick(View v) {
                thePlaceWhereTheArrayWillBeLocated = saveBtnYesFunc(currentYesBtnId);  //Maybe some type casts are needed
                //tempActivityList =activityNames;
                //return activityNames;    //This line is totally incorrect
            }
        });
    }

    void wheneverFunctionYouWant() {
        //do whatever you want with thePlaceWhereTheArrayWillBeLocated 
    }
}