android - How to pass an object between fragments which are in actionbar navigation mode?

Question

In my app there are two fragments (MenuFragment, BasketFragment) and they are located in actionbar tab in navigation mode.

In MenuFragment i hold objects of Product class (Parcelable) in ArrayList in a listview. What i want to do is to carry product to BasketFragment in runtime when i click the item.

I have tried to do that with callback interface and bundle approaches so far and i have always faced with NullPointerException.

Please help me with that. If you would give code example, will be very appreciated.

Answer 1

使用回调接口是正确的方法。如果没有看到你得到的 NullPointerException 的堆栈跟踪，我会假设这是因为回调没有正确设置。我认为如果你这样做，onAttach()它应该可以正常工作：

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    try{
        mCallback = (BasketCallback)activity;
    }catch(ClassCastException ex){
        throw new ClassCastException(activity.getLocalClassName() + " must implement BasketCallback");
    }
}

然后，您可以从您的片段调用您的回调方法，并让活动使用传递对象到第二个片段getSupportFragmentManager().findFragmentById(R.id.basket_fragment);