Android阵列适配器-Getview -Textview引发错误

Question

I have a Lsit View generated using an ArrayAdapter. The TextView field in getView method is throwing error while populating it with the value from POJO class. Could you please let me know where my code needs correction.

Thanks in Advance.

public class ApplianceAdapter extends ArrayAdapter<POJO_Appliance> {
    private ArrayList<POJO_Appliance> appliance;  
    Context context;
    LayoutInflater vi; 
    public ApplianceAdapter(Context context ,ArrayList<POJO_Appliance> appliance) {    
        super(context, 0, appliance); 
        this.appliance = new ArrayList<POJO_Appliance>();    
        this.appliance.addAll(appliance); 
        this.context =context;
        vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);  
    }     
    private class ViewHolder {
        TextView applianceName;     
        Button cancel,edit; 
    } 
    public View getView(final int position, View convertView, ViewGroup parent) {      
        ViewHolder holder;  
        if (convertView == null) { 
            holder = new ViewHolder();  
                convertView    = vi.inflate(R.layout.rowappliance,  null); 
                holder.applianceName    = (TextView) convertView.findViewById(R.id.tvapplianceName);  
                holder.cancel  = (Button)   convertView.findViewById(R.id.bCancel); 
                holder.edit    = (Button)   convertView.findViewById(R.id.bEdit);        
            convertView.setTag(holder); 
        } else {
            holder = (ViewHolder) convertView.getTag();  
        }  

        Log.i("AddAppliance"," Appliance Name : " + appliance.get(position).getApplianceName());
        holder.applianceName.setText(appliance.get(position).getApplianceName());   

        //   Cancel button
        holder.cancel.setTag(position); 
        holder.cancel.setOnClickListener(new View.OnClickListener() {        
            public void onClick(View v) {                   
                try {
                    int pos = (Integer) v.getTag();                         
                    Log.i("ConfirmAdapter ","Order cancel @ position : " + pos);  
                    entry.deleteAppliance(roomName,appliance.get(pos).getApplianceName());
                    refreshAdapter();
                    } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    }  
                }       
            });    
        return convertView; 
        } 
}   

The error log:

01-18 17:28:32.259: E/AndroidRuntime(28641): FATAL EXCEPTION: main
01-18 17:28:32.259: E/AndroidRuntime(28641): java.lang.NullPointerException
01-18 17:28:32.259: E/AndroidRuntime(28641): at com.example.homeauto.AddAppliance$ApplianceAdapter.getView(AddAppliance.java:136)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.AbsListView.obtainView(AbsListView.java:2040)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.ListView.makeAndAddView(ListView.java:1772)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.ListView.fillDown(ListView.java:672)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.ListView.fillFromTop(ListView.java:732)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.ListView.layoutChildren(ListView.java:1611)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.AbsListView.onLayout(AbsListView.java:1870)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.View.layout(View.java:11418)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.ViewGroup.layout(ViewGroup.java:4328)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1652)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1641)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.LinearLayout.onLayout(LinearLayout.java:1417)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.View.layout(View.java:11418)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.ViewGroup.layout(ViewGroup.java:4328)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1652)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1510)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.LinearLayout.onLayout(LinearLayout.java:1415)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.View.layout(View.java:11418)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.ViewGroup.layout(ViewGroup.java:4328)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.FrameLayout.onLayout(FrameLayout.java:443)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.View.layout(View.java:11418)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.ViewGroup.layout(ViewGroup.java:4328)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1652)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1510)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.LinearLayout.onLayout(LinearLayout.java:1415)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.View.layout(View.java:11418)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.ViewGroup.layout(ViewGroup.java:4328)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.widget.FrameLayout.onLayout(FrameLayout.java:443)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.View.layout(View.java:11418)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.ViewGroup.layout(ViewGroup.java:4328)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1489)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.os.Handler.dispatchMessage(Handler.java:99)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.os.Looper.loop(Looper.java:137)
01-18 17:28:32.259: E/AndroidRuntime(28641): at android.app.ActivityThread.main(ActivityThread.java:4441)
01-18 17:28:32.259: E/AndroidRuntime(28641): at java.lang.reflect.Method.invokeNative(Native Method)
01-18 17:28:32.259: E/AndroidRuntime(28641): at java.lang.reflect.Method.invoke(Method.java:511)
01-18 17:28:32.259: E/AndroidRuntime(28641): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-18 17:28:32.259: E/AndroidRuntime(28641): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-18 17:28:32.259: E/AndroidRuntime(28641): at dalvik.system.NativeStart.main(Native Method)

Answer 1

It may be due to wrong reference in findViewById . You should check the id of your text view or layout view :-)