GridView：null对象引用上的getLayoutParams

Question

我有一个gridview，我想在那里展示一些图片。我使用BaseAdapter作为适配器。当我运行代码时，会显示以下消息：

  

java.lang.NullPointerException：尝试调用虚方法   “android.view.ViewGroup $的LayoutParams   关于空对象引用的android.view.View.getLayoutParams（）'。

我甚至不确定它意味着什么...我的代码中没有任何内容表示getLayoutParams（）。我该如何解决这个问题？

savedNewsPapers类：

File file;
StringBuilder text;

String tempFolder = "Fira/HUB/temp/";
String personalInformationFolder = "Fira/HUB/PersonalInformation/";
String favoriteAppsGeneral = "Fira/HUB/FavoriteApps/General/";

static String selectedBoxContent = "";
static int currentNumber = 1;

static ArrayList<String> where;


GridView myGrid;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.saved_news_papers);

    Handler handler = new Handler();
    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            createON();
        }
    }, 1000);


}

private void createON() {
    myGrid = (GridView) findViewById(R.id.gridView);

    loadSubscriptions();
}


private void loadSubscriptions() {
    file = new File(Environment.getExternalStorageDirectory(),personalInformationFolder + "newsSubscription" + Integer.toString(currentNumber) + ".txt");

    if (file.exists()) {
        text = new StringBuilder();
        text.setLength(0);
        try {
            BufferedReader bufferedReader = new BufferedReader(new FileReader(file));
            String line;
            while ((line = bufferedReader.readLine()) != null) {
                text.append(line);
            }
            bufferedReader.close();
        }
        catch (IOException e) {}

        if (!text.toString().isEmpty()) {
            where = new ArrayList<>();
            where.add(text.toString());
            Log.e("got called", "loadSusbscription is not empty");
        }

        Log.e("got called", "loadSubscription");


        text.setLength(0);
        currentNumber = currentNumber + 1;
        loadSubscriptions();
    }else {
        Log.e("got called", "loadSusbscription doesnt exist");
        myGrid.setAdapter(new VivzAdapter(this));
        Log.e("got called", "Adapter set");
    }
}



class VivzAdapter extends BaseAdapter {

    ArrayList<String> list;
    Context context;

    VivzAdapter(Context context) {
        Log.e("got called", "VivzAdapter");
        this.context = context;
        list = savedNewsPapers.where;
    }

    @Override
    public int getCount() {
        Log.e("got called", "getCount");
        return list.size();
    }

    @Override
    public Object getItem(int i) {
        Log.e("got called", "getItem");
        return list.get(i);
    }

    @Override
    public long getItemId(int i) {
        Log.e("got called", "getItemID");
        return i;
    }

    class ViewHolder {
        ImageView myImageView;
        ViewHolder(View v) {
            Log.e("got called", "ViewHolder");
            myImageView = (ImageView) v.findViewById(R.id.imageView);
            Log.e("got called", "ViewHolder found image");
        }
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {

        Log.e("got called", "getView");



        View row = view;
        ViewHolder holder = null;
        if(row == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(R.layout.single_item, viewGroup, false);
            holder = new ViewHolder(row);
            row.setTag(holder);
        }else {
            holder = (ViewHolder) row.getTag();
        }


        String listItem = list.get(i);

        if (listItem.equals("BBC")) {
            Log.e("SUCCESS", "CONG FUCKING GRATULATION!");
            holder.myImageView.setImageResource(R.drawable.amazon_music_with_title);
        }else {
            holder.myImageView.setImageResource(R.drawable.amazon_music_with_title);
        }



        return null;
    }


    private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {

        ImageView bmImage;

        public DownloadImageTask(ImageView bmImage) {
            this.bmImage = bmImage;
        }

        protected Bitmap doInBackground(String... urls) {
            String urldisplay = urls[0];
            Bitmap mIcon11 = null;
            try {
                InputStream in = new java.net.URL(urldisplay).openStream();
                mIcon11 = BitmapFactory.decodeStream(in);
            } catch (Exception e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return mIcon11;
        }

        protected void onPostExecute(Bitmap result) {
            bmImage.setImageBitmap(result);
        }
    }
}