使用片段Android获取mysql数据库信息

Question

我尝试从我的android应用程序中的mysql数据库（phpmyadmin）获取信息。 例如，我使用php文件连接数据库，而其他一些您不需要查看的文件。

我的mainActivity中有以下代码：

String JSON_STRING;
JSONObject jsonObject;
JSONArray jsonArray;
ContactAdapter contactAdapter;
ListView listView;

public void getJSON(View View) 
{
    new BackgroundTask().execute();
}

    class BackgroundTask extends AsyncTask<Void, Void, String> 
    {
        String json_url;

        @Override
        protected void onPreExecute() {

            json_url = "http://firejackal.fr/script.php";
        }

        @Override
        protected String doInBackground(Void... params) {

            try {
                URL url = new URL(json_url);
                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                InputStream inputStream = httpURLConnection.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                StringBuilder stringBuilder = new StringBuilder();
                while ((JSON_STRING = bufferedReader.readLine()) != null) {
                    stringBuilder.append(JSON_STRING + "\n");
                }

                bufferedReader.close();
                inputStream.close();
                httpURLConnection.disconnect();
                return stringBuilder.toString().trim();

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }    

            return null;
        }

        @Override
        protected void onProgressUpdate(Void... values) {
            super.onProgressUpdate(values);
        }

    }

    public void parseJSON(View view) {

        if (JSON_STRING == null) {

            Toast.makeText(getApplicationContext(), "First get JSON", Toast.LENGTH_LONG).show();

        } else {

            Intent intent = new Intent(this, Podium.class);
            intent.putExtra("JSON_DATA", JSON_STRING);
            startActivity(intent);

        }

    }

使用void ParseJSON时，我在podium的OnCreate中使用以下代码在称为podium的新片段上显示信息：

String JSON_STRING;
JSONObject jsonObject;
JSONArray jsonArray;
ContactAdapter contactAdapter;
ListView listView;

listView = (ListView) getView().findViewById(R.id.listview);

contactAdapter = new ContactAdapter(this.getContext(),R.layout.row_layout);
listView.setAdapter(contactAdapter);
JSON_STRING=getActivity().getIntent().getExtras().getString("JSON_DATA");
    try {
        jsonObject = new JSONObject(JSON_STRING);
        jsonArray = jsonObject.getJSONArray("server_response");
        int count = 0;
        String id_post,id_user_post, place_post, date_post;

        while(count < jsonArray.length()){

            JSONObject JO = jsonArray.getJSONObject(count);
            id_user_post = JO.getString("id_user_post");
            place_post = JO.getString("place_post");
            date_post = JO.getString("date_post");

            Contacts contacts = new Contacts(id_user_post, place_post, date_post);
            contactAdapter.add(contacts);
            count++;

        }

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

但是，如果讲台是活动而不是片段，则此代码有效。 但是讲台是一个片段，将此代码放在onCreateView中会使它无法正常工作。

我给你contacts.java：

public class Contacts {

    private String id_user_post, place_post, date_post;

    public Contacts(String id_user_post, String place_post, String date_post){

        this.setId_user_post(id_user_post);
        this.setPlace_post(place_post);
        this.setDate_post(date_post);

    }

    public String getId_user_post() {
        return id_user_post;
    }

    public void setId_user_post(String id_user_post) {
        this.id_user_post = id_user_post;
    }

    public String getPlace_post() {
        return place_post;
    }

    public void setPlace_post(String place_post) {
        this.place_post = place_post;
    }

    public String getDate_post() {
        return date_post;
    }

    public void setDate_post(String date_post) {
        this.date_post = date_post;
    }

}

和contactAdapter.java：

public class ContactAdapter extends ArrayAdapter {

    List list = new ArrayList();

    public ContactAdapter(Context context, int resource) {
        super(context, resource);
    }

    public void add(Contacts object) {
        super.add(object);
        list.add(object);
    }

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

    @Override
    public Object getItem(int position) {
        return list.get(position);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        View row;
        row = convertView;
        ContactHolder contactHolder;

        if(row == null){

            LayoutInflater layoutInflater = (LayoutInflater)this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = layoutInflater.inflate(R.layout.row_layout,parent,false);
            contactHolder = new ContactHolder();
            contactHolder.tx_id_user_post = (TextView)row.findViewById(R.id.tx_id_user_post);
            contactHolder.tx_place_post = (TextView)row.findViewById(R.id.tx_place_post);
            contactHolder.tx_date_post = (TextView)row.findViewById(R.id.tx_date_post);
            row.setTag(contactHolder);

        }else {

            contactHolder = (ContactHolder)row.getTag();
        }

        Contacts contacts = (Contacts)this.getItem(position);
        contactHolder.tx_id_user_post.setText(contacts.getId_user_post());
        contactHolder.tx_place_post.setText(contacts.getPlace_post());
        contactHolder.tx_date_post.setText(contacts.getDate_post());

        return row;
    }

    static class ContactHolder{

        TextView tx_id_user_post, tx_place_post, tx_date_post;

    }
}

那么，您可以帮我适应这一部分，使其片段化吗？

如果您需要查看其他文件，请告诉我。

Answer 1

尝试使用这种方法：

将此代码添加到片段中

public static PodiumFragment newInstance(String  mJsonData) {

    PodiumFragment mFragment = new PodiumFragment();

    Bundle args = new Bundle();
    args.putString("JSON_DATA", mJsonData);
    mFragment.setArguments(args);

    return mFragment;
}

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


    if (getArguments() != null) {
        if(getArguments().containsKey("JSON_DATA")){
            JSON_STRING = getArguments().getString("JSON_DATA");
        }
    }

    //YOUR CODE

}

创建片段时添加以下行：

Fragment fragment = PodiumFragment.newInstance(JSON_STRING);


FragmentManager mFragmentManager = getSupportFragmentManager();
FragmentTransaction mFragmentTransaction =    mFragmentManager.beginTransaction();
mFragmentTransaction.replace(R.id.podium_frament, fragment);
mFragmentTransaction.commit();

Answer 2

我认为你可以使用：contactAdapter = new ContactAdapter（getActivity（），R.layout.row_layout）;

在您的onCreate中放在podiumFragment中。