java - 将查看寻呼机详细信息转换为 json 时出错

Question

在本教程的帮助下，我成功让 Viewpager 工作:http://www.androidbegin.com/tutorial/android-viewpager-gallery-images-and-texts-tutorial/]

现在，我正在尝试将 viewpager 中的数据转换为从网站上的 json 文件检索到的日期。我已经使用代码来检索常规列表，它工作正常，但我无法通过 ViewPager 的适配器查明问题导致此错误:

Error:(159, 31) error: constructor ViewPagerAdapter in class ViewPagerAdapter cannot be applied to given types;
required: Context,String[],String[],String[],int[]
found: Activity,ArrayList<HashMap<String,String>>,String,String,String,String
reason: actual and formal argument lists differ in length

这是 fragment 中的代码:

public class WhatsHotFragment extends Fragment {

private TextView DateView;
private ImageView PhotoView;
private TextView whereView;
private TextView infoView;

ViewPager viewPager;
PagerAdapter adapter;


public WhatsHotFragment() {}



private static final String TAG_OS = "results";

private static final String where = "name";
private static final String date = "dates";
private static final String information = "info";
private static final String flag = "avatar_url";



ArrayList<HashMap<String, String>> oslist = new ArrayList<HashMap<String, String>>();


private static String url = "http://celebirious.com/bey/data/style.json";



JSONArray android = null;


@Override
public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);



}



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



    View v = inflater.inflate(R.layout.fragment_whats_hot, null);

    oslist = new ArrayList<HashMap<String, String>>();
    new JSONParse().execute();

    return v;

}

class JSONParse extends AsyncTask<String, String, JSONObject> {
    private ProgressDialog pDialog;

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        infoView = (TextView) getActivity().findViewById(R.id.info);
        whereView = (TextView) getActivity().findViewById(R.id.where);
        DateView = (TextView) getActivity().findViewById(R.id.date);
        PhotoView = (ImageView) getActivity().findViewById(R.id.photo);
        pDialog = new ProgressDialog(getActivity());
        pDialog.setMessage("Getting Data ...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();

    }

    @Override
    protected JSONObject doInBackground(String... args) {

        JSONParser jParser = new JSONParser();
        JSONObject json = jParser.getJSONFromUrl(url);
        return json;
    }


    @Override
    protected void onPostExecute(JSONObject json) {
        pDialog.dismiss();
        try {

            android = json.getJSONArray(TAG_OS);
            for(int i = 0; i < android.length(); i++){
                JSONObject c = android.getJSONObject(i);


                // Storing  JSON item in a Variable
                String infoView = c.getString(information);
                String dateView = c.getString(date);
                String whereView = c.getString(where);
                String PhotoView = c.getString(flag);


                // Adding value HashMap key => value

                HashMap<String, String> map = new HashMap<String, String>();

                map.put(information, infoView);
                map.put(date, dateView);
                map.put(whereView, where);
                map.put(PhotoView, flag);


                oslist.add(map);

                viewPager = (ViewPager) getActivity().findViewById(R.id.pager);
                adapter = new ViewPagerAdapter(getActivity(), oslist, where, date, information, flag);

                viewPager.setAdapter(adapter);


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

    }



}





 }

在 ViewPagerAdapter 中，代码如下:

public class ViewPagerAdapter extends PagerAdapter {
// Declare Variables
Context context;
String[] where;
String[] date;
String[] information;
int[] flag;
LayoutInflater inflater;

public ViewPagerAdapter(Context context, String[] where, String[] date,
        String[] information, int[] flag) {
    this.context = context;
    this.where = where;
    this.date = date;
    this.information = information;
    this.flag = flag;
}

@Override
public int getCount() {
    return where.length;
}

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

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

    // Declare Variables
    TextView txtrank;
    TextView txtcountry;
    TextView txtpopulation;
    ImageView imgflag;

    inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View itemView = inflater.inflate(R.layout.styledeets, container,
            false);

    // Locate the TextViews in viewpager_item.xml
    txtrank = (TextView) itemView.findViewById(R.id.date);
    txtcountry = (TextView) itemView.findViewById(R.id.where);
    txtpopulation = (TextView) itemView.findViewById(R.id.info);

    // Capture position and set to the TextViews
    txtrank.setText(where[position]);
    txtcountry.setText(date[position]);
    txtpopulation.setText(information[position]);

    // Locate the ImageView in viewpager_item.xml
    imgflag = (ImageView) itemView.findViewById(R.id.photo);
    // Capture position and set to the ImageView
    imgflag.setImageResource(flag[position]);

    // Add viewpager_item.xml to ViewPager
    ((ViewPager) container).addView(itemView);

    return itemView;
}

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
    ((ViewPager) container).removeView((RelativeLayout) object);

}
}

我的猜测是这样的: 公共(public) ViewPagerAdapter(Context context, String[] where, String[] date, String[] 信息，int[] 标志) { this.context = 上下文； this.where = 哪里； this.date = 日期； this.信息 = 信息； this.flag = 标志； }

问题是由适配器引起的 - 请问如何解决？

Answer 1

问题是您的 ViewPagerAdapter 类有一个构造函数，要求 Context 上下文、String[] where、String[] date、String[] information、int[] flag -

public ViewPagerAdapter(Context context, String[] where, String[] date,
        String[] information, int[] flag) {
    this.context = context;
    this.where = where;
    this.date = date;
    this.information = information;
    this.flag = flag;
}

但是你正在给予Activity,ArrayList<HashMap<String,String>>,String,String,String,String

您应该将构造函数更改为 -

public ViewPagerAdapter(Context context, ArrayList<HashMap<String,String>> map ,String s1,String s2,String s3,String s4) {
        ///implementation
    }

更多。

你应该改变这行代码，现在它在for循环中，这意味着你在每次迭代时都执行这个操作，将其放在for循环之外:

for(int i = 0; i < android.length(); i++){
            JSONObject c = android.getJSONObject(i);


            // Storing  JSON item in a Variable
            String infoView = c.getString(information);
            String dateView = c.getString(date);
            String whereView = c.getString(where);
            String PhotoView = c.getString(flag);


            // Adding value HashMap key => value

            HashMap<String, String> map = new HashMap<String, String>();

            map.put(information, infoView);
            map.put(date, dateView);
            map.put(whereView, where);
            map.put(PhotoView, flag);


            oslist.add(map);

            viewPager = (ViewPager) getActivity().findViewById(R.id.pager);
            adapter = new ViewPagerAdapter(getActivity(), oslist, where, date, information, flag);

            viewPager.setAdapter(adapter);


        }

更多:

AsyncTask - 不要使用这个，如果 Activity 在操作完成之前丢失，它会给你带来问题。查看 Retrofit 或/和 Okhttp，或者至少使用 AsyncTaskLoader。对于 Json 操作，请查看 Gson 或 Jackson 库。