moveToIndex method
Moves to a specific index in the playlist
Returns true if successful, false if the index is out of bounds
Implementation
bool moveToIndex(int index) {
if (_sources.isEmpty || index < 0 || index >= _sources.length) {
return false;
}
if (_currentIndex == index) {
return true;
}
_currentIndex = index;
_notifyIndexChanged();
return true;
}