Fragment的Android通话活动导致应用崩溃

Question

我试图从一个片段中调用我的活动，但它在启动时崩溃。

这是调用活动的片段代码（扩展SherlockFragment）：

public class SalesOrder extends SherlockFragment{

    ListView myInfoList;
    String[] items = {"Item 1", "Item 2"};
    ArrayAdapter<CharSequence> adapter;

    ArrayList<MessageDetails> details;
    AdapterView.AdapterContextMenuInfo info;

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){

        View view = inflater.inflate(R.layout.sales_order, container, false);

        return view;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onActivityCreated(savedInstanceState);
        refreshListView();
    }

    private void refreshListView()
    {
        myInfoList = (ListView)getActivity().findViewById(R.id.MessageList);
        adapter = new ArrayAdapter<CharSequence>(getActivity().getApplicationContext(), android.R.layout.simple_list_item_1, items);
        myInfoList.setAdapter(adapter);

        details = new ArrayList<MessageDetails>();
        MessageDetails Detail;

        //CHANGE THIS PART TO RETRIEVE DATABASE ITEM DYNAMICALLY
        List<String> itemName = new ArrayList<String>();
        itemName.add("Shirt Design 1");
        itemName.add("Shirt Design 2");
        itemName.add("Shirt Design 3");

        List<Float> itemPrice = new ArrayList<Float>();
        itemPrice.add(14f);
        itemPrice.add(15f);
        itemPrice.add(16f);

        List<String> description = new ArrayList<String>();
        description.add("This is a fine shirt 1");
        description.add("This is a fine shirt 2");
        description.add("This is a fine shirt 3");

        Detail = new MessageDetails();

        for (int i =0; i < itemName.size(); i++)
        {
            Detail = new MessageDetails();
            Detail.setSub(itemName.get(i));
            Detail.setSubValue(itemPrice.get(i));
            Detail.setDescription(description.get(i));
            details.add(Detail);
        }   

        myInfoList.setAdapter(new CustomAdapter(details , getActivity().getApplicationContext()));

        myInfoList.setOnItemClickListener(new OnItemClickListener() {
               public void onItemClick(AdapterView<?> a, View v, int position, long id) {
                   //System.out.println("Name: "+details.get(position).getSub();
                   //String s = details.get(position).getDescription();

                   Intent i = new Intent(getActivity(), purchase.class);
                   getActivity().startActivity(i);
               }
       });  
    }

    public class CustomAdapter extends BaseAdapter {

        private ArrayList<MessageDetails> _data;
        Context _c;

        CustomAdapter (ArrayList<MessageDetails> data, Context c){
            _data = data;
            _c = c;
        }

        public int getCount() {
            // TODO Auto-generated method stub
            return _data.size();
        }

        public Object getItem(int position) {
            // TODO Auto-generated method stub
            return _data.get(position);
        }

        public long getItemId(int position) {
            // TODO Auto-generated method stub
            return position;
        }

        public View getView(final int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
             View v = convertView;
             if (v == null) 
             {
                LayoutInflater vi = (LayoutInflater)_c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                v = vi.inflate(R.layout.mysaleslistview, null);
             }
               TextView subView = (TextView)v.findViewById(R.id.itemName);
               TextView subValueView = (TextView)v.findViewById(R.id.itemPrice);

               MessageDetails msg = _data.get(position);
               subView.setText(msg.sub);    
               subValueView.setText(msg.subValue.toString());             

            return v; 
    }
    }

    public class MessageDetails {
        String sub, description;
        Float subValue;

        public String getSub() {
            return sub;
        }

        public void setSub(String sub) {
            this.sub = sub;
        }

        public Float getSubValue() {
            return subValue;
        }

        public void setSubValue(Float subValue) {
            this.subValue = subValue;
        }

        public String getDescription() {
            return description;
        }

        public void setDescription(String description) {
            this.description = description;
        }
    }
}

我的活动称为（扩展活动）：

public class purchase extends Activity {

    Button Btnpurchase;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.purchase);
        Btnpurchase = (Button) findViewById(R.id.btnPurchase);
    }

}

而我的logcat：

07-04 23:35:46.318: E/AndroidRuntime(7924): FATAL EXCEPTION: main
07-04 23:35:46.318: E/AndroidRuntime(7924): java.lang.NullPointerException
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.support.v4.app.FragmentManagerImpl.saveFragmentBasicState(FragmentManager.java:1576)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.support.v4.app.FragmentManagerImpl.saveAllState(FragmentManager.java:1617)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.support.v4.app.FragmentActivity.onSaveInstanceState(FragmentActivity.java:481)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at com.actionbarsherlock.app.SherlockFragmentActivity.onSaveInstanceState(SherlockFragmentActivity.java:127)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.app.Activity.performSaveInstanceState(Activity.java:1155)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1216)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3258)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.app.ActivityThread.handleStopActivity(ActivityThread.java:3318)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.app.ActivityThread.access$900(ActivityThread.java:156)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1277)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.os.Looper.loop(Looper.java:137)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at android.app.ActivityThread.main(ActivityThread.java:5233)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at java.lang.reflect.Method.invokeNative(Native Method)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at java.lang.reflect.Method.invoke(Method.java:511)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:799)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:566)
07-04 23:35:46.318: E/AndroidRuntime(7924):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

将您的意图更改为此：

Intent i = new Intent(getActivity(), purchaseDialog.class);

PS

命名Activity类purchaseDialog不是好习惯，恕我直言。

Answer 2

试试下面

Intent i = new Intent(getActivity(), purchaseDialog.class);
startActivity(i);

一个建议试试这个

myInfoList = (ListView)view.findViewById(R.id.MessageList);

Answer 3

您没有提及在其中具有“片段”的活动被称为什么。 我现在仅将其MyActivity 。

尝试：

Intent i = new Intent(MyActivity.this, purchase.class);
MyActivity.this.startActivity(i);