android高效编程之使用本地变量

hava a look at the following code you will find that

 

 We assign the mNotesCursor field to a local variable at the start of the method. This is done as an optimization of the Android code. Accessing a local variable is much more efficient than accessing a field in the Dalvik VM, so by doing this we make only one access to the field, and five accesses to the local variable, making the routine much more efficient. It is recommended that you use this optimization when possible

 

 

   @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);
       
        Cursor c = mNotesCursor;//We assign the mNotesCursor field to a local variable
        c.moveToPosition(position);
        Intent i = new Intent(this,NoteEdit.class);
        i.putExtra(NotesDbAdapter.KEY_ROWID, id);
        i.putExtra(NotesDbAdapter.KEY_TITLE,
                c.getString(c.getColumnIndex(NotesDbAdapter.KEY_TITLE)));
        i.putExtra(NotesDbAdapter.KEY_BODY,
                c.getString(c.getColumnIndex(NotesDbAdapter.KEY_BODY)));
        startActivityForResult(i, ACTIVITY_EDIT);
       
    }