Question

我的片段中有ViewPager，并且我正尝试从服务器加载ViewPager中的图像。已成功从Logcat的服务器中获取图像，但无法在视图分页器中显示，并且应用崩溃。

它在日志猫中显示以下错误：

java.lang.NullPointerException: Argument must not be null
    at com.bumptech.glide.util.Preconditions.checkNotNull(Preconditions.java:31)
    at com.bumptech.glide.util.Preconditions.checkNotNull(Preconditions.java:25)
    at com.bumptech.glide.RequestBuilder.into(RequestBuilder.java:675)
    at Adapters.HomeOfferAdapter.instantiateItem(HomeOfferAdapter.java:57)
    at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:1010)
    at android.support.v4.view.ViewPager.populate(ViewPager.java:1158)
    at android.support.v4.view.ViewPager.populate(ViewPager.java:1092)
    at android.support.v4.view.ViewPager.setAdapter(ViewPager.java:540)
    at com.app.bookbudiapp.Home$4$1.run(Home.java:371)
    at android.os.Handler.handleCallback(Handler.java:790)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:7000)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:441)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1408)

这是我的下面的代码：

HomeOfferAdapter.java

public class HomeOfferAdapter extends PagerAdapter {

private Context context;
private LayoutInflater layoutInflater;
private List<HomeOffersModel> banners;

public HomeOfferAdapter(List<HomeOffersModel> banners,Context context){

             this.banners = banners;
             this.context = context;
}

@Override
public int getCount() {
    return banners.size();
}

@Override
public boolean isViewFromObject(@NonNull View view, @NonNull Object o) {
    return view == o;
}

@NonNull
@Override
public Object instantiateItem(@NonNull ViewGroup container, int position) {

    layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    assert layoutInflater != null;
    View view = layoutInflater.inflate(R.layout.onboard_frag,container,false);

    ImageView slideImage = view.findViewById(R.id.offerImage);

    HomeOffersModel model = banners.get(position);

    RequestOptions options = new RequestOptions();
    options.placeholder(R.drawable.openbook);

    Glide.with(context).load(model.getOffers()).apply(options).into(slideImage);

    container.addView(view);

    return view;
}

@Override
public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
    container.removeView((LinearLayout)object);
  }
}

Home.java

public class Home extends Fragment {

ViewPager homeOffers;
HomeOfferAdapter offerAdapter;
List<HomeOffersModel> banners;

private static final String HOME_OFFERS = "https://example.com";

public Home() {
    // Required empty public constructor
    } 

 @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.fragment_home, container, false);

    homeOffers = view.findViewById(R.id.homeOffers);

    banners = new ArrayList<>();

     OkHttpClient client = new OkHttpClient.Builder()
                          .connectTimeout(22,TimeUnit.SECONDS)
                          .readTimeout(22,TimeUnit.SECONDS)
                          .writeTimeout(22,TimeUnit.SECONDS)
                          .build();

    Request request = new Request.Builder().url(HOME_OFFERS).build();

    client.newCall(request).enqueue(new Callback() {

        @Override
        public void onResponse(Call call, final Response response) throws IOException {

            if(getActivity() != null) {

                getActivity().runOnUiThread(new Runnable() {
                    @Override
                    public void run() {

                        try {

                            JSONArray jsonArray = new JSONArray(response.body().string());

                            for (int i=0 ; i<jsonArray.length(); i++) {

                                JSONObject jsonObject = jsonArray.getJSONObject(i);

                                String str = jsonObject.getString("Image");

                                Log.d("response",str);

                                HomeOffersModel model = new HomeOffersModel(str);
                                banners.add(model);

                            }

                            offerAdapter = new HomeOfferAdapter(banners, getActivity());
                            homeOffers.setAdapter(offerAdapter);

                        } catch (JSONException e) {
                            e.printStackTrace();
                        } catch (IOException e) {
                            e.printStackTrace();
                        } finally {

                            response.close();
                        }
                    }
                });

            }
        }

        @Override
        public void onFailure(Call call, final IOException e) {

            getActivity().runOnUiThread(new Runnable() {
                @Override
                public void run() {

                    TastyToast.makeText(getActivity(),e.getMessage(),TastyToast.LENGTH_SHORT,TastyToast.ERROR).show();
                }
            });
        }

    });

    return view;
   }
}

HomeOffersModel.java

public class HomeOffersModel {

String offers;

public HomeOffersModel(){

}

public HomeOffersModel(String offers){

    this.offers = offers;
}

public String getOffers() {
    return offers;
}

public void setOffers(String offers) {
    this.offers = offers;
 }
}

有人请让我知道为什么我已经正确设置了适配器，但还是收到上述错误。任何帮助将不胜感激。

谢谢

图像未加载到视图分页器中

0 个答案: