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POfatal error - null pointer exception
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  1. POfatal error - null pointer exception
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    copied!<p>im getting an a null pointer error, i can't find whats wrong with it. This is the activity code</p> <pre><code> package ie.gmit.gmitapp; import android.os.Bundle; import android.app.ListActivity; import android.content.Context; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.LinearLayout; import android.widget.ListView; import android.widget.TextView; public class BusinessActivity extends ListActivity { protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //setContentView(R.layout.activity_bussiness); //use our own list adapter setListAdapter(new BusinessListAdapter(this)); } protected void onListItemClick(ListView l, View v, int position, long id) { ((BusinessListAdapter)getListAdapter()).toggle(position); } /** * A sample ListAdapter that presents content * from arrays of text and titles. * */ private class BusinessListAdapter extends BaseAdapter { public BusinessListAdapter(Context context) { mContext = context; } /** * The number of items in the list is determined by the number of speeches * in our array. * * @see android.widget.ListAdapter#getCount() */ public int getCount() { return mTitles.length; } /** * Since the data comes from an array, just returning * the index is sufficent to get at the data. If we * were using a more complex data structure, we * would return whatever object represents one * row in the list. * * @see android.widget.ListAdapter#getItem(int) */ public Object getItem(int position) { return position; } /** * Use the array index as a unique id. * @see android.widget.ListAdapter#getItemId(int) */ public long getItemId(int position) { return position; } /** * Make a DescriptionView to hold each row. * @see android.widget.ListAdapter#getView(int, android.view.View, android.view.ViewGroup) */ public View getView(int position, View convertView, ViewGroup parent) { DescriptionView dv; if (convertView == null) { dv = new DescriptionView(mContext, mTitles[position], mDescription[position], mExpanded[position]); } else { dv = (DescriptionView)convertView; dv.setTitle(mTitles[position]); dv.setDescription(mDescription[position]); dv.setExpanded(mExpanded[position]); } return dv; } public void toggle(int position) { mExpanded[position] = !mExpanded[position]; notifyDataSetChanged(); } /** * Remember our context so we can use it when constructing views. */ private Context mContext; /** * Our data, part 1. */ private String[] mTitles = { "Bachelor of Business", "Bachelor of Business (Honours)" }; private String[] mDescription = { "This programme provides you with a broadly-based business education" + " to assist you to work successfully in business. You will study a variety " + "of business subjects and develop a general understandng of the administrative, " + "economics, legal, and social environment within which business operates. You will " + "study the basics of business and get an insight into many business disciplines" + " in years one and two. In year three you can specialise in Marketing, Human" + " Resource Management, or Information Systems Management. There is a strong " + "emphasis during the programme on practical business projects to develop the" + "skills required by graduates in the workplace. (Students may apply to the" + " Registrar for a Higher Certificate in Business after successfully completing " + "two years of the programme.)", "The School of Business offers a four-year honours degree (Level 8) in Business. " + "This programme provides students with a broad-based business education to work" + " successfully in business and offers students the opportunity to specialise in one " + "of five streams. You will study a variety of business subjects and develop a general" + " understanding of the administrative, economic, legal and social environment within" + " which business operates. You will study the basics of business and get an insight" + " into many business disciplines in years one and two. In year three you can specialise " + "in marketing, human resource management or information systems management. In year four " + "you can specialise in economics and finance, human resource management, management," + " marketing or rural enterprise and agri-business. There is a strong emphasis on the" + " current business environment and acquiring the skills and knowledge required for " + "employment in business. Case studies and practical business projects are used to develop" + " students' analysis, communication and professional business skills." }; /** * Our data, part 3. */ private boolean[] mExpanded = { false, false, }; } /** * We will use a DescriptionView to display each speech. It's just a LinearLayout * with two text fields. * */ private class DescriptionView extends LinearLayout { private TextView mTitle; private TextView mDescription; public DescriptionView(Context context, String title, String desc, boolean expanded) { super(context); this.setOrientation(VERTICAL); // Here we build the child views in code. They could also have // been specified in an XML file. mTitle = new TextView(context); mTitle.setText(title); addView(mTitle, new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT)); mDescription.setText(desc); addView(mDescription, new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT)); mDescription.setVisibility(expanded ? VISIBLE : GONE); } /** * Convenience method to set the title of a DescriptionView */ public void setTitle(String title) { mTitle.setText(title); } /** * Convenience method to set the description of a DescriptionView */ public void setDescription(String words) { mDescription.setText(words); } /** * Convenience method to expand or hide the description */ public void setExpanded(boolean expanded) { mDescription.setVisibility(expanded ? VISIBLE : GONE); } } } </code></pre> <p>here is the log cat:</p> <pre><code>03-25 13:34:07.753: E/AndroidRuntime(912): FATAL EXCEPTION: main 03-25 13:34:07.753: E/AndroidRuntime(912): java.lang.NullPointerException 03-25 13:34:07.753: E/AndroidRuntime(912): at ie.gmit.gmitapp.BusinessActivity$DescriptionView.&lt;init&gt;(BusinessActivity.java:174) 03-25 13:34:07.753: E/AndroidRuntime(912): at ie.gmit.gmitapp.BusinessActivity$BusinessListAdapter.getView(BusinessActivity.java:82) 03-25 13:34:07.753: E/AndroidRuntime(912): at android.widget.AbsListView.obtainView(AbsListView.java:2159) 03-25 13:34:07.753: E/AndroidRuntime(912): at android.widget.ListView.makeAndAddView(ListView.java:1831) </code></pre> <p>line 174 is</p> <pre><code>mDescription.setText(desc) </code></pre> <p>and line 82 is</p> <pre><code>dv = new DescriptionView(mContext, mTitles[position], mDescription[position], mExpanded[position]); </code></pre>
 

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