java - Working with HashMap it shown an error?

Question

I am working with hash map and it shows an error:-

The method add(HashMap<String,String>) in the type ArrayList<HashMap<String,String>> is not applicable for the arguments (String)

on this line:

songsList.add(fullpath);

---

EDIT:

private ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();
private Cursor musiccursor, videocursor; // projection for audio media files
String[] music = { MediaStore.Audio.Media._ID,MediaStore.Audio.Media.DATA,MediaStore.Audio.Media.DI‌​SPLAY_NAME, MediaStore.Video.Media.SIZE }; // projection for video media files
String[] video = { MediaStore.Video.Media._ID,MediaStore.Video.Media.DATA,MediaStore.Video.Media.DI‌​SPLAY_NAME, MediaStore.Video.Media.SIZE };

Answer 1

HashMap 是一个泛型。它可以采用任何单一类型的变量，但它只能采用它被声明为的类型。如果看起来这被声明为采用 ArrayList 但您尝试添加字符串，反之亦然。