Using a Context Menu to delete from a SQLite database in Android

I have created a list view that displays the n开发者_JAVA百科ames and dates of items stored in a SQLite database, now I want to use a Context Menu to modify these items stored in the database such as edit the name, delete, and view.

This is the code for the list view:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.listview);

    SQLiteDatabase myDB = null; 
    myDB = this.openOrCreateDatabase(MY_DB_NAME, MODE_PRIVATE, null);

    Cursor cur = myDB.rawQuery("SELECT _id, trackname, tracktime" + " FROM " + MY_DB_TABLE, null);
    ListAdapter adapter = new SimpleCursorAdapter(this, R.layout.listview, cur,
    new String[] { Constants.TRACK_NAME, Constants.TRACK_TIME}, new int[] { R.id.text1, R.id.text2});
    ListView list = (ListView)findViewById(R.id.list);
    list.setAdapter(adapter);
    registerForContextMenu(list);
}

and the Context Menu...

public void onCreateContextMenu(ContextMenu menu, View v,
        ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    menu.setHeaderTitle("Track Options");
    menu.add(0, CHANGE_NAME, 0, "Change name");

    menu.add(0, VIEW_TRACK, 0, "View track");

    menu.add(0, SEND_TRACK, 0, "Send track");

    menu.add(0, DELETE_TRACK, 0, "Delete track");


}

I have used a Switch statement to control the menu items..

public boolean onContextItemSelected(MenuItem item) {
   switch (item.getItemId()){
   case CHANGE_NAME:
       changename();
       return true;

   case DELETE_TRACK:
       deletetrack();
       return true;

   default:
   return super.onContextItemSelected(item);
}

So how would I go ahead and map the deletetrack(); method to find the ID of the track stored in the database to the item that has been selected in the list view?

in your onContextItemSelected(), do something like this:

@Override
public boolean onContextItemSelected(MenuItem item) {
    AdapterView.AdapterContextMenuInfo info = 
        (AdapterView.AdapterContextMenuInfo)item.getMenuInfo();

            Track track = (Track)mAdapter.getItem(info.position);

The key is "position", which will give you the index of the item selected.

I tried this method and many others but none worked for me. This is how I finally got it work:

1. I created a method in my database handler class (your class that extends SQLiteOpenHelper) that retrieves all the ids in my database:

public ArrayList<HashMap<String, String>> selectAllIds() {
    try {
        ArrayList<HashMap<String, String>> idArrayList = new ArrayList<HashMap<String, String>>();
        HashMap<String, String> map;

        SQLiteDatabase database = this.getReadableDatabase();

        String query = "SELECT * FROM " + DEBTS_TABLE_NAME;

        Cursor cursor = database.rawQuery(query, null);

        if (cursor != null) {
            if (cursor.moveToFirst()) {
                do {
                    map = new HashMap<String, String>();
                    map.put("id", cursor.getString(0));
                    idArrayList.add(map);

                } while (cursor.moveToNext());
            }
        }
        if (cursor != null) {
            cursor.close();
        }
        database.close();
        return idArrayList;


    } catch (Exception e) {
        return null;
    }

}

2. In the class or Fragment that has the onContextItemSelected method, declare this:

 ArrayList<HashMap<String, String>> myIds;

3. Then in my onContextItemSelected method:

public boolean onContextItemSelected(MenuItem item) {
    AdapterView.AdapterContextMenuInfo info =

 (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();

    myIds = debtDatabaseHandler.selectAllIds();
    int id = Integer.parseInt(myIds.get(info.position).get("id"));

the id in my database is of type Integer that's why I had to parse it.If your id is a String, just do:

String id = myIds.get(info.position).get("id");

4. Finally, pass this id to the call to delete a row in the database:

yourDatabase.deleteMethod(id);

Idea Credit: Android Delete Rows Data in SQLite Database (Android SQLite)

I can't add comment to @synic 's answer, but it's totally works for me. The code below can get the item of Listview:

AdapterView.AdapterContextMenuInfo info = 
            (AdapterView.AdapterContextMenuInfo)aItem.getMenuInfo();

Then you can do what you want to the item, like getId(), getName(), getDate() or something. Wish you glad.