Take values from ArrayList<HashMap<String, String>> [closed]

问题

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.

Closed 6 years ago.

I have a problem about getting a value from my ArrayList<HashMap<String, String>>.

My code is:

ArrayList<HashMap<String, String>> myArrayList;

and then:

HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
myArrayList.add(map);

If I want to get the name, for example, I tried as follow but I obtain a runtime error (the application crashes):

System.out.println(myArrayList.get(1).get(TAG_NAME));

How can I solve it?

Thank you very much!

回答1:

System.out.println(myArrayList.get(1).get(TAG_NAME));

ArrayList is 0-based. get(0) instead.

回答2:

You can loop through the list like this

   for(Map<String, String> map : myArrayList)
    {
        String tagName = map.get(TAG_NAME);
        System.out.println(tagNAme);
    }

来源：https://stackoverflow.com/questions/16544928/take-values-from-arraylisthashmapstring-string