使用 json rereiver php mysql 在片段中填充列表视图

Posted 2023-04-18

【中文标题】使用 json rereiver php mysql 在片段中填充列表视图

【英文标题】：populate a listview in fragment with a json rereiver php mysql

【发布时间】：2019-11-02 11:40:41

【问题描述】：

我对片段相当陌生，但我的代码对我来说似乎足够合乎逻辑，但它仍然崩溃或根本没有结果我不知道它出了什么问题，我从 php 获取一个 json 文件api，包括解析它们并将它们列在片段内的列表视图中的“Annances”广告， 这是我的片段类和适配器

如果有人可以参考我可以学习的代码或提供线索我哪里出错了，谢谢

public class MainFragment extends Fragment

private String URLstring = "http://192.168.1.38/api/annonce/read.php";
private static ProgressDialog mProgressDialog;
private ListView lv;
ArrayList<DataModel> dataModelArrayList = new ArrayList<DataModel> ();
private ListAdapter1 listAdapter1;

public static MainFragment newInstance() 
    MainFragment fragment = new MainFragment();
    return fragment;


@Override
public void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);


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

    View v=inflater.inflate(R.layout.main_fragment, container, false);


    lv  = v.findViewById(R.id.lv);

    new JsonTask().execute(URLstring); 
    return v;


private class JsonTask extends AsyncTask<String, String, String> 
    protected void onPreExecute() 

    

    protected String doInBackground(String... params) 
        HttpURLConnection connection = null;
        BufferedReader reader = null;
        try 
            URL url = new URL(params[0]);
            connection = (HttpURLConnection) url.openConnection();
            connection.connect();
            InputStream stream = connection.getInputStream();
            reader = new BufferedReader(new InputStreamReader(stream));
            StringBuffer buffer = new StringBuffer();
            String line;
            String file_name="";
            while ((line = reader.readLine()) != null) 
                try 
                    JSONObject dataobj = new JSONObject(line);
                    DataModel playerModel = new DataModel();
                    playerModel.setPhoto_principale(dataobj.getString("Photo_principale"));
                    playerModel.setTitre_annonce(dataobj.getString("Titre_annonce"));
                    playerModel.setDescription(dataobj.getString("Description"));
                    playerModel.setQuartier(dataobj.getString("Quartier"));
                    dataModelArrayList.add(playerModel);
                
                catch (Exception e)
                buffer.append(line + "\n");
            
            return buffer.toString();
         catch (MalformedURLException e) 
            e.printStackTrace();
         catch (IOException e) 
            e.printStackTrace();
         finally 
            if (connection != null) 
                connection.disconnect();
            
            try 
                if (reader != null) 
                    reader.close();
                
             catch (IOException e) 
                e.printStackTrace();
            
        
        return null;
    


    @Override
    protected void onPostExecute(String result) 

        super.onPostExecute(result);
        setupListview();

    





private void setupListview()
    removeSimpleProgressDialog();  //will remove progress dialog
    listAdapter1 = new ListAdapter1(getActivity(),dataModelArrayList); // Here we talk about getActivity() because you are using Fragment not 
    //an actual activity so you call it getActivity()
    lv.setAdapter(listAdapter1);



public static void removeSimpleProgressDialog() 
    try 
        if (mProgressDialog != null) 
            if (mProgressDialog.isShowing()) 
                mProgressDialog.dismiss();
                mProgressDialog = null;
            
        
     catch (IllegalArgumentException ie) 
        ie.printStackTrace();

     catch (RuntimeException re) 
        re.printStackTrace();
     catch (Exception e) 
        e.printStackTrace();
    

这是适配器类

public class ListAdapter1 extends BaseAdapter 

private Context context;
private ArrayList<DataModel> dataModelArrayList;
public ListAdapter1(Context context, ArrayList<DataModel> dataModelArrayList) 

    this.context = context;
    this.dataModelArrayList = dataModelArrayList;

@Override
public int getViewTypeCount() 
    return getCount();

@Override
public int getItemViewType(int position) 

    return position;


@Override
public int getCount() 
    return dataModelArrayList.size();


@Override
public Object getItem(int position) 
    return dataModelArrayList.get(position);


@Override
public long getItemId(int position) 
    return 0;


@Override
public View getView(int position, View convertView, ViewGroup parent) 
    ViewHolder holder;

    if (convertView == null) 
        holder = new ViewHolder();
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.item_list, null);

        holder.photo_principale = (ImageView) convertView.findViewById(R.id.image);
        holder.titre_annonce = (TextView) convertView.findViewById(R.id.titre_annonce);
        holder.description = (TextView) convertView.findViewById(R.id.description);
        holder.quartier = (TextView) convertView.findViewById(R.id.quartier);

        convertView.setTag(holder);
    else 
        // the getTag returns the viewHolder object set as a tag to the view
        holder = (ViewHolder)convertView.getTag();
    

    Picasso.get().load(dataModelArrayList.get(position).getPhoto_principale()).into(holder.photo_principale);
    holder.titre_annonce.setText(dataModelArrayList.get(position).getTitre_annonce());
    holder.description.setText(dataModelArrayList.get(position).getDescription());
    holder.quartier.setText(dataModelArrayList.get(position).getQuartier());

    return convertView;


private class ViewHolder 
    // changed protected to public
    public  TextView titre_annonce, description, quartier;
    public ImageView photo_principale;

【参考方案1】：

使用 volley 库来处理 JSON。 看看这个答案 How do you use the android Volley API?

其他链接

https://www.geeksforgeeks.org/volley-library-in-android/ https://developer.android.com/training/volley/index.html

一些重要的检查点

在电脑上测试url 测试你的手机是否连接到localhost，查看这个链接https://www.webucator.com/blog/2016/05/accessing-your-local-web-server-from-a-mobile-device-using-xampp/

同时

在onCreateView方法中实例化适配器类并传递相关参数

@覆盖 public View onCreateView(LayoutInflater inflater, ViewGroup 容器, 捆绑 savedInstanceState)

View v=inflater.inflate(R.layout.main_fragment, container, false);


lv  = v.findViewById(R.id.lv);
//note this change
listAdapter1 = new ListAdapter1(getActivity(),dataModelArrayList);

new JsonTask().execute(URLstring); 
return v;

但是为了简化你的工作，下次就用凌空抽球