Question

我的var obj = localStorage.getItem('obj'); if(obj !== null) { .... //show the obj in label or do what you want with it ... }出现错误，这是我的代码，错误指向此代码，其错误指向Adapter，它说：

错误：类型不兼容：HomeFragment无法转换为上下文

HomeFragment.java

这是我的 HomeFragment.java

adapter = new Adapter(models,this);

然后是我的 Adapter.java

public class HomeFragment extends Fragment {

    //cardview
    ViewPager viewPager;
    Adapter adapter;
    List<Model> models;
    Integer[]colors = null;
    ArgbEvaluator argbEvaluator = new ArgbEvaluator();


    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_home,container,false);

        //cardview
        models = new ArrayList<>();
        models.add(new Model(R.drawable.brochure,"Brochure","Lorem ipsum dolor sit amet"));
        models.add(new Model(R.drawable.sticker,"Sticker","Lorem ipsum dolor sit amet"));
       models.add(new Model(R.drawable.poster,"Poster","Lorem ipsum dolor sit amet"));
       models.add(new Model(R.drawable.namecard,"Name Card","Lorem ipsum dolor sit amet"));

        adapter = new Adapter(models,this);

        viewPager = getView().findViewById(R.id.viewPager);
        viewPager.setAdapter(adapter);
        viewPager.setPadding(130,0,130,0);
    }
}

Answer 1

更改此：

adapter = new Adapter(models,this);

对此：

adapter = new Adapter(models, (Context) getActivity());

您必须通过Context。并且Activity可以强制转换为Context，而Fragment不能强制转换。

因此，您必须检索Activity正在执行的当前getActivity()的实例。

如果您想在Adapter中创建Activity的实例，则可以通过简单地传递this来实现，就像我之前说过的，强制转换Activity -可以Context，但不能Fragment。因此Activity将被强制转换为Context，但是当您想在Fragment中创建相同内容时，就不能简单地传递this，从而引发错误。 / p>

正如您在评论中所说，现在还有另一个错误，这是因为您已经在该方法的第一行return处获得了某些内容，因此，该行下的每一行将永远无法到达，这就是为什么出现该错误，请放置此行

return inflater.inflate(R.layout.fragment_home,container,false);

最后，错误将消失。

在您的方法中进行了更多编辑之后，您的OnCreateView将看起来像这样：

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

    view = inflater.inflate(R.layout.fragment_home, container, false); // Created a instance of View which we can return later.

    //cardview
    models = new ArrayList<>();
    models.add(new Model(R.drawable.brochure,"Brochure","Lorem ipsum dolor sit amet"));
    models.add(new Model(R.drawable.sticker,"Sticker","Lorem ipsum dolor sit amet"));
    models.add(new Model(R.drawable.poster,"Poster","Lorem ipsum dolor sit amet"));
    models.add(new Model(R.drawable.namecard,"Name Card","Lorem ipsum dolor sit amet"));

    adapter = new Adapter(models,this);

    viewPager = view.findViewById(R.id.viewPager); // Change getView() to view here.
    viewPager.setAdapter(adapter);
    viewPager.setPadding(130,0,130,0);

    return view; // Returned the view.
}

Answer 2

使用this代替getActivity()

更改此

adapter = new Adapter(models,this);

到

adapter = new Adapter(models,getActivity());

错误：类型不兼容：HomeFragment无法转换为上下文

2 个答案: