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POWhy am I getting an NPE error when using my custom listview adapter?
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copied!<p>This would be a lengthy question with lots of code in it so to those who would take time to read it Thank you so much!</p> <p>So basically I have an application made using Eclipse. The MAIN ACTIVITY is extended as FragmentActivity, called MenuMain.java. This activity have three fragments defined in its xml. And the one I am having problems with is the third one.</p> <p>What I want to do is when the user clicks a button on the middle fragment, it would add content into a custom listview which is the third fragment.</p> <p>Here is my class for displaying the content on the middle fragment.</p> <p>ImageFragment.java</p> <pre><code>package com.thesis.menubook; import java.util.ArrayList; import android.app.ProgressDialog; import android.os.AsyncTask; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentTransaction; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.RelativeLayout; import android.widget.TextView; import android.widget.Toast; public class ImageFragment extends Fragment { ProgressDialog pDialog; private int imageResourceId; private ArrayList<String> menu_id = new ArrayList<String>(); private ArrayList<String> menu_name = new ArrayList<String>(); private ArrayList<String> menu_description = new ArrayList<String>(); int page = 0; String orderQuantity = ""; EditText quantity; ListView lv; public ImageFragment(int imageResource, ArrayList<String> mid, ArrayList<String> mname, ArrayList<String> mdesc, int pg) { this.imageResourceId = imageResource; this.menu_id = mid; this.menu_name = mname; this.menu_description = mdesc; this.page = pg; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.layout_menu, container, false); Button next = (Button)view.findViewById(R.id.next); Button back = (Button)view.findViewById(R.id.back); Button add = (Button)view.findViewById(R.id.add); quantity = (EditText) view.findViewById(R.id.editText1); RelativeLayout layout = (RelativeLayout) view.findViewById(R.id.main_layout); layout.setBackgroundResource(imageResourceId); //Change ID on Layout TextView id = (TextView) view.findViewById(R.id.menu_id); id.setText(menu_id.get(page)); //Change name on layout TextView name = (TextView) view.findViewById(R.id.menu_name); name.setText(menu_name.get(page)); //change description on layout TextView desc = (TextView) view.findViewById(R.id.menu_description); desc.setText(menu_description.get(page)); // set next page button listener next.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View v){ if(page < menu_id.size()-1) { page++; Toast.makeText(getActivity(), "Next", Toast.LENGTH_LONG).show(); loadMenuItem(page); } else { Toast.makeText(getActivity(), "You are at the end of the page", Toast.LENGTH_LONG).show(); } } }); // set back page button listener back.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View v){ if(page != 0) { page--; Toast.makeText(getActivity(), "Next", Toast.LENGTH_LONG).show(); loadMenuItem(page); } else { Toast.makeText(getActivity(), "You are at the start of the page", Toast.LENGTH_LONG).show(); } } }); //set add to orderlist button listener add.setOnClickListener( new View.OnClickListener() { @Override public void onClick(View v) { if(quantity.getText().toString() != "" || quantity.getText().toString() != "0" || quantity.getText().toString() != "00"){ lv = (ListView) v.findViewById(R.id.orderListView); new AddToList().execute(""); } else { Toast.makeText(getActivity(), "Please put quantity", Toast.LENGTH_LONG).show(); } } }); return view; } public void loadMenuItem(int pahina) { FragmentManager fm = getFragmentManager(); if (fm != null) { FragmentTransaction ft = fm.beginTransaction(); ft.replace(R.id.menu_fragment, new ImageFragment(R.drawable.caesar_salad, menu_id, menu_name,menu_description, pahina)); ft.commit(); } } class AddToList extends AsyncTask<String, String, String> { ArrayList<DataArray> dataArray = new ArrayList<DataArray>(); DataArray data = new DataArray(); /** * Before starting background thread Show Progress Dialog * */ @Override protected void onPreExecute() { super.onPreExecute(); pDialog = new ProgressDialog(getActivity()); Log.d("Activity Context", getActivity().toString() + ""); pDialog.setMessage("Adding to list. Please wait..."); pDialog.setIndeterminate(false); pDialog.setCancelable(false); pDialog.show(); } /** * Getting product details in background thread * */ protected String doInBackground(String... param) { data.setID(menu_id.get(page)); data.setName(menu_name.get(page)); data.setQuantity(quantity.getText().toString()); dataArray.add(data); Log.d("Order Data ID: ", data.getID() + ""); Log.d("Order Data Name: ", data.getName() + ""); Log.d("Order Data Quantity: ", data.getQuantity() + ""); return null; } /** * After completing background task Dismiss the progress dialog * **/ @Override protected void onPostExecute(String result) { pDialog.dismiss(); lv.setAdapter(new MyCustomAdapter(getActivity(), dataArray)); } } } </code></pre> <p>I get an error here when I call my custom adapter in this line <code>lv.setAdapter(new MyCustomAdapter(getActivity(), dataArray));</code> which is on the onPostExecute()</p> <p>I define my custom adapter like this</p> <p>MyCustomAdapter.java</p> <pre><code>package com.thesis.menubook; import java.util.ArrayList; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.TextView; public class MyCustomAdapter extends BaseAdapter { private static ArrayList<DataArray> orderData; private LayoutInflater mInflater; public MyCustomAdapter(Context context, ArrayList<DataArray> passed) { orderData = passed; mInflater = LayoutInflater.from(context); } public int getCount() { return orderData.size(); } public Object getItem(int position) { return orderData.get(position); } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder; if (convertView == null) { convertView = mInflater.inflate(R.layout.custom_order_list, null); holder = new ViewHolder(); holder.txtID = (TextView) convertView.findViewById(R.id.id); holder.txtName = (TextView) convertView.findViewById(R.id.name); holder.txtQuantity = (TextView) convertView.findViewById(R.id.quantity); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } holder.txtID.setText(orderData.get(position).getID()); holder.txtName.setText(orderData.get(position).getName()); holder.txtQuantity.setText(orderData.get(position).getQuantity()); return convertView; } static class ViewHolder { TextView txtID; TextView txtName; TextView txtQuantity; } } </code></pre> <p>And my custom variable DataArray.java is like this. I have no problems with DataArray though as it logs content so I am sure the NPE error does not refer to my use of this class</p> <p>package com.thesis.menubook;</p> <p>public class DataArray {</p> <pre><code> private String menu_ID = ""; private String menu_name = ""; private String quantity = ""; public void setID(String ID) { this.menu_ID = ID; } public String getID() { return menu_ID; } public void setName(String menu_name) { this.menu_name = menu_name; } public String getName() { return menu_name; } public void setQuantity(String quantity) { this.quantity = quantity; } public String getQuantity(){ return quantity; } } </code></pre> <p>I think the problem is because of the <code>getActivity()</code> in this line <code>lv.setAdapter(new MyCustomAdapter(getActivity(), dataArray));</code> on ImageFragment. I have tried:</p> <pre><code>getActivity().getApplicationCOntext() getActivity().getBaseContext() getActivity().getParent().getApplicationContext() getActivity().getParent().getBaseContext() </code></pre> <p>to NO avail.</p> <p>So how do I get around this? </p> <p>Here are the other less important classes and xml files which you may need to analyze to help me.</p> <p>OrderListFragment.java</p> <pre><code>package com.thesis.menubook; import android.annotation.TargetApi; import android.os.Build; import android.os.Bundle; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; @TargetApi(Build.VERSION_CODES.HONEYCOMB) public class OrderListFragment extends Fragment{ @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.activity_order_list, container, false); return view; } } </code></pre> <p>activity_order_list.xml</p> <pre><code><?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <TextView android:id="@+id/orderlist" android:layout_width="505dp" android:layout_height="wrap_content" android:paddingLeft="6dip" android:paddingTop="6dip" android:text="@string/orderlist" android:textSize="17sp" android:textStyle="bold" /> <ListView android:id="@+id/orderListView" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout> </code></pre> <p>custom_order_list.xml</p> <pre><code><?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" android:paddingBottom="10dip" android:paddingLeft="10dip" android:paddingTop="10dip" > <TextView android:id="@+id/id" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textColor="#C20000" android:textSize="14sp" android:textStyle="bold" /> <TextView android:id="@+id/name" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/quantity" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </LinearLayout> </code></pre> <p>activity_menu_main.xml</p> <pre><code><?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id = "@+id/activity_main_large" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="horizontal" xmlns:tools="http://schemas.android.com/tools"> <fragment android:id="@+id/menu_category_fragment" android:name="com.thesis.menubook.MenuCategory" android:layout_width="0dip" android:layout_height="match_parent" android:layout_weight="0.14" layout="@layout/activity_menu_category" /> <fragment android:id="@+id/menu_fragment" android:name="com.thesis.menubook.MenuFragment" android:layout_width="0dip" android:layout_height="match_parent" android:layout_weight="0.71" layout="@layout/activity_menu_fragment" /> <fragment android:id="@+id/orderlist_fragment" android:name="com.thesis.menubook.OrderListFragment" android:layout_width="167dp" android:layout_height="match_parent" layout="@layout/activity_order_list" /> </LinearLayout> </code></pre> <p>layout_menu.xml (the middle fragment content xml)</p> <pre><code><?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/main_layout" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@drawable/caesar_salad" android:gravity="top|bottom|center_vertical" android:paddingLeft="16dp" android:paddingRight="16dp" android:paddingTop="16dp" android:visibility="visible" > <TextView android:id="@+id/menu_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/menu_name" android:textSize="40sp" android:background="#2f000000" android:textColor = "@android:color/white"/> <TextView android:id="@+id/menu_id" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/menu_name" android:textSize="40sp" android:layout_marginLeft="10dp" android:layout_toRightOf="@+id/menu_name" android:background="#2f000000" android:textColor = "@android:color/white" android:visibility="invisible"/> <TableLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/tableLayout1" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_below="@+id/menu_name" android:layout_marginTop="20dp" > <TableRow android:id="@+id/tableRow1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="5dip" > <TextView android:id="@+id/menu_description" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="#2f000000" android:textColor="@android:color/white" android:textSize="20sp" android:textStyle="italic" android:typeface="sans" android:text ="@string/menu_description" android:layout_margin="10dp"> </TextView> <TextView android:id="@+id/menu_price" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="#2f000000" android:textColor="@android:color/white" android:textSize="20sp" android:textStyle="italic" android:typeface="sans" android:text ="@string/menu_price" android:layout_margin="10dp"/> </TableRow> </TableLayout> <TextView android:id="@+id/quantity" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/menu_description" android:layout_alignParentBottom="true" android:layout_marginBottom="20dp" android:background="#2f000000" android:text="@string/quantity" android:textColor="@android:color/white" android:textSize="25sp" android:textStyle="italic" android:typeface="sans"/> <EditText android:id="@+id/editText1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@+id/quantity" android:layout_alignTop="@+id/quantity" android:layout_centerHorizontal="true" android:layout_toRightOf="@+id/quantity" android:layout_marginLeft="5dp" android:background="@android:color/white" android:ems="2" android:maxLength="2" android:inputType="number"> <requestFocus /> </EditText> <Button android:id="@+id/add" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBaseline="@+id/editText1" android:layout_toRightOf="@+id/editText1" android:layout_centerHorizontal="true" android:text="@string/add" android:textColor="@android:color/white"/> <Button android:id="@+id/next" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_above="@+id/tableLayout1" android:layout_alignRight="@+id/tableLayout1" android:layout_marginRight="42dp" android:text="@string/next" android:textSize="20sp" /> <Button android:id="@+id/back" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_above="@+id/tableLayout1" android:layout_marginRight="26dp" android:layout_toLeftOf="@+id/next" android:text="@string/back" android:textSize="20sp" /> </RelativeLayout> </code></pre> <p>Here is my LogCat</p> <pre><code>02-16 13:25:25.541: D/Order Data ID:(502): 001 02-16 13:25:25.541: D/Order Data Name:(502): Chicken 02-16 13:25:25.541: D/Order Data Quantity:(502): 8 02-16 13:25:25.865: E/AndroidRuntime(502): FATAL EXCEPTION: main 02-16 13:25:25.865: E/AndroidRuntime(502): java.lang.NullPointerException 02-16 13:25:25.865: E/AndroidRuntime(502): at com.thesis.menubook.ImageFragment$AddToList.onPostExecute(ImageFragment.java:182) 02-16 13:25:25.865: E/AndroidRuntime(502): at com.thesis.menubook.ImageFragment$AddToList.onPostExecute(ImageFragment.java:1) 02-16 13:25:25.865: E/AndroidRuntime(502): at android.os.AsyncTask.finish(AsyncTask.java:590) 02-16 13:25:25.865: E/AndroidRuntime(502): at android.os.AsyncTask.access$600(AsyncTask.java:149) 02-16 13:25:25.865: E/AndroidRuntime(502): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:603) 02-16 13:25:25.865: E/AndroidRuntime(502): at android.os.Handler.dispatchMessage(Handler.java:99) 02-16 13:25:25.865: E/AndroidRuntime(502): at android.os.Looper.loop(Looper.java:132) 02-16 13:25:25.865: E/AndroidRuntime(502): at android.app.ActivityThread.main(ActivityThread.java:4025) 02-16 13:25:25.865: E/AndroidRuntime(502): at java.lang.reflect.Method.invokeNative(Native Method) 02-16 13:25:25.865: E/AndroidRuntime(502): at java.lang.reflect.Method.invoke(Method.java:491) 02-16 13:25:25.865: E/AndroidRuntime(502): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841) 02-16 13:25:25.865: E/AndroidRuntime(502): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599) 02-16 13:25:25.865: E/AndroidRuntime(502): at dalvik.system.NativeStart.main(Native Method) 02-16 13:25:26.587: D/dalvikvm(502): GC_CONCURRENT freed 126K, 7% free 7635K/8199K, paused 23ms+35ms 02-16 13:25:32.642: I/Process(502): Sending signal. PID: 502 SIG: 9 </code></pre>

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