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PONullPointException on making an arraylist of objects in android
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  1. PONullPointException on making an arraylist of objects in android
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    copied!<p>I'm new in android programming . I'm writing an android program which has two tabs: detailstab in which user fill a form and hit save button. listtab in which display what user insert in edittexts control in details tab. to implement this i made this classes:</p> <p>detail java class :</p> <pre><code>import android.widget.RadioButton; import android.widget.TextView; public class detail { public TextView tvName; public TextView tvAdr; public TextView tvNote; public RadioButton rb_0; public RadioButton rb_1; public RadioButton rb_2; public int radioValue; //public final TextView tvRadioValue=null; } </code></pre> <p>details activity class in which i make an arraylist and add objects from detail:</p> <pre><code>import java.util.ArrayList; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.RadioButton; import android.widget.RadioGroup; import android.widget.TextView; public class details extends Activity { public ArrayList&lt;detail&gt; detaillist=new ArrayList&lt;detail&gt;(); public EditText etName; public EditText etAdr; public EditText etNote; public RadioGroup rg; public RadioButton rb_0; public RadioButton rb_1; public RadioButton rb_2; static details detailsActivity; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); detailsActivity=this; setContentView(R.layout.details_tab); Button btnSave=(Button) findViewById(R.id.button1); //define an arraylist to add detail object to it etName=(EditText) findViewById(R.id.editText1); etAdr=(EditText) findViewById(R.id.editText2); etNote=(EditText) findViewById(R.id.editText3); rg=(RadioGroup) findViewById(R.id.radioGroup1); rb_0=(RadioButton) findViewById(R.id.radio0); rb_1=(RadioButton) findViewById(R.id.radio1); rb_2=(RadioButton) findViewById(R.id.radio2); btnSave.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View arg0) { final detail d=new detail(); makeDetailList(d); //clear textboxes clear(etName); clear(etAdr); clear(etNote); rg.check(R.id.radio0); } }); } public void clear(View v) { EditText edittext=new EditText(null); edittext.setText(""); } public ArrayList&lt;detail&gt; makeDetailList(detail d){ d.tvName.setText(etName.getText()); d.tvAdr.setText(etAdr.getText()); //d.tvNote.setText(etNote.getText()); if(rb_0.isSelected()) { d.radioValue=0; //d.tvRadioValue.setText(rb_0.getText()); } else if (rb_1.isSelected()) { d.radioValue=1; //d.tvRadioValue.setText(rb_1.getText()); } else if (rb_1.isSelected()) { d.radioValue=2; //d.tvRadioValue.setText(rb_2.getText()); } detaillist.add(d); return detaillist; } public static details getInstance(){ return detailsActivity; } } </code></pre> <p>and finally lists activity class this class contains a listview to display data from details tab:</p> <pre><code> public class list extends Activity { //details details=new details(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.list_tab); ListView lv=(ListView) findViewById(R.id.listView1); //details details=new details(); //ArrayList mylist=details.getInstance().detaillist; MyAdapter adapter=new MyAdapter(this,android.R.layout.simple_list_item_1 , R.id.textView1, details.getInstance().detaillist); lv.setAdapter(adapter); // ArrayAdapter&lt;details&gt; adapter=new ArrayAdapter&lt;details&gt;(this,R.layout.my_list,R.id.textView1,R.id.textView2,)); } private class MyAdapter extends ArrayAdapter&lt;String&gt;{ public MyAdapter(Context context, int resource, int textViewResourceId, ArrayList&lt;detail&gt; detaillist) { super(context, resource, textViewResourceId); // TODO Auto-generated constructor stub } @Override public View getView(int position, View convertView, ViewGroup parent) { LayoutInflater inflater=(LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); View row=inflater.inflate(R.layout.my_list, parent,false); ArrayList&lt;detail&gt; items=details.getInstance().detaillist; ImageView ivR=(ImageView) row.findViewById(R.id.imageView1); TextView tvN=(TextView) row.findViewById(R.id.textView1); TextView tvA=(TextView) row.findViewById(R.id.textView2); tvN.setText(items.get(position).tvName.getText()); tvA.setText(items.get(position).tvAdr.getText()); if(items.get(position) != null) { if(items.get(position).radioValue==0) { ivR.setImageResource(R.drawable.t); } else if(items.get(position).radioValue==1) { ivR.setImageResource(R.drawable.t); } else if(items.get(position).radioValue==2) { ivR.setImageResource(R.drawable.t); } } return row; } } } </code></pre> <p>I receive a NullPointException error onmakeDetailList(d) method . where is the problem? I really appreciate your help best regards</p>
 

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