Jsonを通じてデータベースからデータを取得する方法は？

Question

私はスピナー項目を選択している間、データベースからデータを取得したいと思います。 は、ここで私は、両方のJavaファイルを貼り付けている私の

package com.example.sachin.omcommunication; 

import android.content.Context; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.BaseAdapter; 
import android.widget.TextView; 

import java.util.ArrayList; 
import java.util.HashMap; 

public class ListViewAdapter3 extends BaseAdapter { 
    Context cntx; 

    ArrayList<String> itemwod = new ArrayList<String>(); 
    ArrayList<String> itemorder = new ArrayList<String>(); 
    ArrayList<String> item_remark= new ArrayList<String>(); 
    ArrayList<String> item_date = new ArrayList<String>(); 

    LayoutInflater inflater; 
    ArrayList<HashMap<String, String>> data; 


    public ListViewAdapter3(Context context, 
          ArrayList<String> itm_wod, 
          ArrayList<String> itm_order, 
          ArrayList<String> itm_remark, 
          ArrayList<String> itm_date 
    ) { 
     // TODO Auto-generated constructor stub 
     cntx = context; 


     itemwod = itm_wod; 
     itemorder = itm_order; 
     item_remark = itm_remark; 
     item_date = itm_date; 


    } 

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

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

    @Override 
    public long getItemId(int position) { 
     return position; 
    } 

    @SuppressWarnings("deprecation") 
    public View getView(final int position, View convertView, ViewGroup parent) { 

     TextView orderWOD, order, order_remarks, order_date; 

     inflater = (LayoutInflater) cntx 
       .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 

     LayoutInflater inflater = LayoutInflater.from(cntx); 
     convertView = inflater.inflate(R.layout.raw_order, parent, 
       false); 


     orderWOD = (TextView) convertView.findViewById(R.id.orderWOD); 
     order = (TextView) convertView.findViewById(R.id.order); 
     order_remarks = (TextView) convertView.findViewById(R.id.order_remarks); 
     order_date = (TextView) convertView.findViewById(R.id.order_date); 

     orderWOD.setText(itemwod.get(position)); 
     order.setText(itemorder.get(position)); 
     order_remarks.setText(item_remark.get(position)); 
     order_date.setText(item_date.get(position)); 


     return convertView; 
    } 

} 

Listviewadapter3.java

、今

package com.example.sachin.omcommunication; 

import android.app.Activity; 
import android.app.Fragment; 
import android.app.ProgressDialog; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.support.design.widget.Snackbar; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ArrayAdapter; 
import android.widget.Button; 
import android.widget.ListView; 
import android.widget.Spinner; 
import android.widget.TextView; 

import org.apache.http.NameValuePair; 
import org.apache.http.message.BasicNameValuePair; 
import org.json.JSONArray; 
import org.json.JSONObject; 

import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 

public class Order extends Fragment { 
    private Spinner today; 
    private String[] strtoday; 
    private TextView orderWOD,order,order_remarks,order_date; 
    private ListView lv; 
    private Button btnorder; 
    Activity activity; 


    private static final String TAG_SUCCESS = "success"; 
    static String TAG_RESULTS = "Order"; 
    //static String TAG_VISIT = "VISIT"; 
    static String TAG_O_PARTIES= "o_parties"; 
    static String TAG_O_PRODUCT= "o_product"; 
    static String TAG_O_REMARK = "o_remark"; 
    static String TAG_O_DATE= "o_date"; 
    String cat = "21"; 

    String strtodaystr; 
    JSONObject jsonobject; 
    //JSONArray jsonarray; 
    // String img; 
    ListViewAdapter3 listadapter3; 
    ProgressDialog mProgressDialog; 

    ArrayList<HashMap<String, String>> arraylist; 
    // private static String url_profile ="http://websofthub.co.in/fetchmember.php"; 
    private static String url_profile = "http://10.0.2.2/portal/fetchorder.php"; 
    // String g; 

    JSONParser jParser = new JSONParser(); 

    ArrayList<String> itemwod = new ArrayList<String>(); 
    ArrayList<String> itemorder = new ArrayList<String>(); 
    ArrayList<String> item_remark= new ArrayList<String>(); 
    ArrayList<String> item_date = new ArrayList<String>(); 


    View view; 
    public Order(){}; 


    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     // Inflate the layout for this fragment 
     // don't look at this layout it's just a listView to show how to handle the keyboard 
     View view = inflater.inflate(R.layout.activity_order, container, false); 
     getActivity().setTitle("Order"); 
     lv = (ListView) view.findViewById(R.id.listvieworder); 
     today = (Spinner) view.findViewById(R.id.today); 
     btnorder = (Button) view.findViewById(R.id.btnorder); 

     orderWOD = (TextView) view.findViewById(R.id.orderWOD); 
     order = (TextView) view.findViewById(R.id.order); 
     order_remarks = (TextView) view.findViewById(R.id.order_remarks); 
     order_date = (TextView) view.findViewById(R.id.order_date); 

     strtoday = getResources().getStringArray(R.array.visit); 
     ArrayAdapter<String> adaptertoday= new ArrayAdapter<String>(activity, android.R.layout.simple_spinner_item, strtoday); 
     adaptertoday.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
     today.setAdapter(adaptertoday); 


     btnorder.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       strtodaystr = today.getSelectedItem().toString(); 

       //listvieworder.clearChoices(); 
       itemwod.clear(); 
       itemorder.clear(); 
       item_remark.clear(); 
       item_date.clear(); 

       new DownloadJSON().execute(); 

      } 
     }); 
     return view; 
    } 

    private class DownloadJSON extends AsyncTask<Void, Void, Void> { 

     @Override 
     protected void onPreExecute() { 
      super.onPreExecute(); 
      // Create a progressdialog 
      mProgressDialog = new ProgressDialog(getActivity()); 

      mProgressDialog.setTitle("Please Wait"); 
      // Set progressdialog message 
      mProgressDialog.setMessage("Loading..."); 
      mProgressDialog.setIndeterminate(false); 
      // Show progressdialog 
      mProgressDialog.show(); 

     } 
     @Override 
     protected Void doInBackground(Void... args) { 
      // Create an array 
      try { 
       arraylist = new ArrayList<HashMap<String, String>>(); 

       List<NameValuePair> params = new ArrayList<NameValuePair>(); 
       params.add(new BasicNameValuePair(TAG_O_DATE, strtodaystr)); 
       JSONObject json = jParser.makeHttpRequest(url_profile, "GET", params); 
       int success1 = Integer.parseInt(json.getString(TAG_SUCCESS)); 
       Log.d("success", json.toString()); 
       if (success1 == 0) { 
        Snackbar.make(view, "Not Data Found", Snackbar.LENGTH_LONG).show(); 
       } 
       if (success1 == 1) { 
        JSONArray ownerObj = json.getJSONArray("Ordera"); 

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

         jsonobject = ownerObj.getJSONObject(i); 

         //if (jsonobject.getString(TAG_M_YEAR).equalsIgnoreCase(stryearstr) || jsonobject.getString(TAG_M_MONTH).equalsIgnoreCase(strmonthstr)) { 
         itemwod.add(jsonobject.getString(TAG_O_PARTIES)); 
         itemorder.add(jsonobject.getString(TAG_O_PRODUCT)); 
         item_remark.add(jsonobject.getString(TAG_O_REMARK)); 
         item_date.add(jsonobject.getString(TAG_O_DATE)); 


         Log.d("today", itemwod.get(0)); 
         //} 
        } 
       } 
      } catch (Exception e) { 

      } 
      return null; 
     } 

     @Override 
     protected void onPostExecute(Void args) { 
      // Locate the listview in listview_main.xml 
      listadapter3 = new ListViewAdapter3(getActivity(), itemwod, itemorder, item_remark, item_date); 

      // Set the adapter to the ListView 
      lv.setAdapter(listadapter3); 
      // Close the progressdialog 
      mProgressDialog.dismiss(); 
     } 
    } 
} 

Order.java

を私のプロジェクトの完全なコード..

を貼り付けました。..

今、.xmlファイル

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" 
    tools:context="com.example.sachin.omcommunication.Order"> 
    <LinearLayout 
     android:layout_height="wrap_content" 
     android:layout_width="match_parent" 
     android:layout_marginTop="20dp" 
     android:orientation="horizontal"> 

     <Spinner 
      android:id="@+id/today" 
      android:layout_width="200dp" 
      android:layout_height="40dp" 
      android:layout_weight="1" 
      android:layout_gravity="center" 
      android:gravity="center" 
      android:entries="@array/visit" 
      /> 

     <Button 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="Submit" 
      android:id="@+id/btnorder" 
      android:layout_weight="1" 
      android:textSize="20dp"/> 

    </LinearLayout> 



    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="0dp" 
     android:layout_marginTop="10dp" 
     android:layout_weight="10" 
     android:orientation="vertical"> 

     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="0dp" 
      android:layout_weight="3"> 

      <View 
       android:layout_width="match_parent" 
       android:layout_height="4dp" 
       android:background="#a35870"></View> 
     </LinearLayout> 

     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="0dp" 
      android:layout_weight="98" 
      android:orientation="horizontal"> 

      <LinearLayout 
       android:layout_width="0dp" 
       android:layout_height="match_parent" 
       android:layout_weight="17" 
       android:background="#FFAE5E5E" 
       android:orientation="horizontal"> 

       <LinearLayout 
        android:layout_width="0dp" 
        android:layout_height="match_parent" 
        android:layout_weight="98" 
        android:orientation="horizontal"> 

        <TextView 
         android:id="@+id/orderWOD" 
         android:layout_width="match_parent" 
         android:layout_height="match_parent" 
         android:layout_gravity="center" 
         android:gravity="center" 
         android:text="WOD" 
         android:textAppearance="?android:attr/textAppearanceMedium" 
         android:textColor="#000" 
         android:textSize="13dp" 
         android:textStyle="bold" /> 
       </LinearLayout> 

       <LinearLayout 
        android:layout_width="0dp" 
        android:layout_height="match_parent" 
        android:layout_weight="2" 
        android:orientation="horizontal"> 

        <View 
         android:layout_width="2dp" 
         android:layout_height="match_parent" 
         android:background="#fff"></View> 
       </LinearLayout> 

      </LinearLayout> 

      <LinearLayout 
       android:layout_width="0dp" 
       android:layout_height="match_parent" 
       android:layout_weight="18" 
       android:background="#FFAE5E5E" 
       android:orientation="horizontal"> 

       <LinearLayout 
        android:layout_width="0dp" 
        android:layout_height="match_parent" 
        android:layout_weight="98" 
        android:orientation="horizontal"> 

        <TextView 
         android:id="@+id/order" 
         android:layout_width="match_parent" 
         android:layout_height="match_parent" 
         android:layout_gravity="center" 
         android:gravity="center" 
         android:text="Order" 
         android:textAppearance="?android:attr/textAppearanceMedium" 
         android:textColor="#000" 
         android:textSize="13dp" 
         android:textStyle="bold" /> 

       </LinearLayout> 

       <LinearLayout 
        android:layout_width="0dp" 
        android:layout_height="match_parent" 
        android:layout_weight="2" 
        android:orientation="horizontal"> 

        <View 
         android:layout_width="2dp" 
         android:layout_height="match_parent" 
         android:background="#fff"></View> 
       </LinearLayout> 
      </LinearLayout> 
      <LinearLayout 
       android:layout_width="0dp" 
       android:layout_height="match_parent" 
       android:layout_weight="18" 
       android:background="#FFAE5E5E" 
       android:orientation="horizontal"> 

       <LinearLayout 
        android:layout_width="0dp" 
        android:layout_height="match_parent" 
        android:layout_weight="98" 
        android:orientation="horizontal"> 

        <TextView 
         android:id="@+id/order_remarks" 
         android:layout_width="match_parent" 
         android:layout_height="match_parent" 
         android:layout_gravity="center" 
         android:gravity="center" 
         android:text="Remarks" 
         android:textAppearance="?android:attr/textAppearanceMedium" 
         android:textColor="#000" 
         android:textSize="13dp" 
         android:textStyle="bold" /> 

       </LinearLayout> 

       <LinearLayout 
        android:layout_width="0dp" 
        android:layout_height="match_parent" 
        android:layout_weight="2" 
        android:orientation="horizontal"> 

        <View 
         android:layout_width="2dp" 
         android:layout_height="match_parent" 
         android:background="#fff"></View> 
       </LinearLayout> 
      </LinearLayout> 


      <LinearLayout 
       android:layout_width="0dp" 
       android:layout_height="match_parent" 
       android:layout_weight="14" 
       android:background="#FFAE5E5E" 
       android:orientation="horizontal"> 

       <TextView 
        android:id="@+id/order_date" 
        android:layout_width="match_parent" 
        android:layout_height="match_parent" 
        android:layout_gravity="center" 
        android:gravity="center" 
        android:text="Date" 
        android:textAppearance="?android:attr/textAppearanceMedium" 
        android:textColor="#000" 
        android:textSize="13dp" 
        android:textStyle="bold" /> 
      </LinearLayout> 
     </LinearLayout> 

     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="0dp" 
      android:layout_weight="2" 
      android:orientation="vertical"> 

      <View 
       android:layout_width="match_parent" 
       android:layout_height="2dp" 
       android:background="#a35870"></View> 

     </LinearLayout> 
    </LinearLayout> 



    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="0dp" 
     android:layout_marginTop="10dp" 
     android:layout_weight="73" 
     android:orientation="vertical"> 

     <ListView 
      android:id="@+id/listvieworder" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" /> 
    </LinearLayout> 
</LinearLayout> 

私はリストビューデータを表示するためのraw.xmlを作成しました。 最後にはのようなエラーが表示されます。

E/AndroidRuntime: FATAL EXCEPTION: main 
Process: com.example.sachin.omcommunication, PID: 23880 
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference 
at android.view.LayoutInflater.from(LayoutInflater.java:229) 
at android.widget.ArrayAdapter.<init>(ArrayAdapter.java:178) 
at android.widget.ArrayAdapter.<init>(ArrayAdapter.java:137) 
at com.example.sachin.omcommunication.Order.onCreateView(Order.java:86) 
at android.app.Fragment.performCreateView(Fragment.java:2220) 
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:973) 
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1148) 
at android.app.BackStackRecord.run(BackStackRecord.java:793) 
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1535) 
at android.app.FragmentManagerImpl$1.run(FragmentManager.java:482) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
08-31 13:18:35.120 23880-23880/com.example.sachin.omcommunication I/Process: Sending signal. PID: 23880 SIG: 9 

Answer 1

あなたが使用する前に、あなたの活動を初期化 あなたのフラグメント内のinit活動ではなかったので、あなたはcom.example.sachin.omcommunication.Order.onCreateView(Order.java:86) でNullPointerExceptionを得ました。

activity = getActivity();