Question

我在一个活动中集成了两个片段。一个片段具有可扩展列表视图，另一个片段具有列表中所选项目的详细信息。据我所知，没有活动，我们无法将值从一个活动传递到另一个活动。所以我在列表片段中创建了Interface并添加了以下代码。

    OnItemSelectedListener mCallback;

public interface OnItemSelectedListener {
    public void onItemSelected(int menuID, String sShortDesc, String sDescription, double dRate);
}

@Override
public void onAttach(Activity activity) {
    // TODO Auto-generated method stub
    super.onAttach(activity);

    mCallback = (OnItemSelectedListener) activity;

}

并且在项目选择的事件中，我添加了以下代码。

            mCallback.onItemSelected(oALMenu.get(groupPosition).getCategoryMenuItem().get(childPosition).getMenuID() , oALMenu.get(groupPosition).getCategoryMenuItem().get(childPosition).getItemShortDesc(),oALMenu.get(groupPosition).getCategoryMenuItem().get(childPosition).getDescription(), oALMenu.get(groupPosition).getCategoryMenuItem().get(childPosition).getRate());

现在，我已经在我的主要活动中实现了接口，并实现了如下方法。

    @Override
public void onItemSelected(int menuID, String sShortDesc, String sDescription, double dRate) {
    // TODO Auto-generated method stub
    Detail_Fragment oDetail_Fragment = (Detail_Fragment) getFragmentManager().findFragmentById(R.id.fragment_Details);
    System.out.println (">> " + oDetail_Fragment);
    System.out.println(">> " + menuID + " >> " + sShortDesc);
    if(oDetail_Fragment != null)
        oDetail_Fragment.setValue(menuID, sShortDesc, sDescription, dRate);

}

根据System.out语句，我获得此级别的值，但无法更新详细信息片段上的组件。

详细碎片代码如下。

public class Detail_Fragment extends Fragment {


TextView oTVShortDesc, oTVDescription, oTVRate;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    System.out.println("Value : onCreateView");
    Bundle oBundle = getArguments();

    View oView = inflater.inflate(R.layout.layout_detail_fragment, null,false);
    oTVShortDesc = (TextView) oView.findViewById(R.id.tvItemShortDesc);
    oTVDescription = (TextView) oView.findViewById(R.id.tvDescription);
    oTVRate = (TextView) oView.findViewById(R.id.tvRate);

    return oView;
}

public void setValue(int iMenuID, String sShortDesc, String sDescription, double dRate){
    System.out.println("Value : " + oTVShortDesc);

    TextView oTVShortDesc = (TextView) getView().findViewById(R.id.tvItemShortDesc);
    System.out.println("Value : " + oTVShortDesc);
    TextView oTVDescription = (TextView) getView().findViewById(R.id.tvDescription);
    TextView oTVRate = (TextView) getView().findViewById(R.id.tvRate);

    oTVShortDesc.setText(sShortDesc);
    oTVShortDesc.setTag(iMenuID);
    oTVDescription.setText(sDescription);
    oTVRate.setText(String.valueOf(dRate));
}

}

在上面运行代码时遇到以下错误。

    02-07 17:09:59.938: E/AndroidRuntime(25817): FATAL EXCEPTION: main
02-07 17:09:59.938: E/AndroidRuntime(25817): Process: com.agilissystems.restaurantapp, PID: 25817
02-07 17:09:59.938: E/AndroidRuntime(25817): java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
02-07 17:09:59.938: E/AndroidRuntime(25817):    at com.agilissystems.restaurantapp.Detail_Fragment.setValue(Detail_Fragment.java:38)
02-07 17:09:59.938: E/AndroidRuntime(25817):    at com.agilissystems.restaurantapp.MenuActivity.onItemSelected(MenuActivity.java:139)
02-07 17:09:59.938: E/AndroidRuntime(25817):    at com.agilissystems.restaurantapp.List_Fragment$MenuExpandableListViewAdapter.getChildView(List_Fragment.java:278)
02-07 17:09:59.938: E/AndroidRuntime(25817):    at android.widget.ExpandableListConnector.getView(ExpandableListConnector.java:451)
02-07 17:09:59.938: E/AndroidRuntime(25817):    at android.widget.AbsListView.obtainView(AbsListView.java:2344)
02-07 17:09:59.938: E/AndroidRuntime(25817):    at android.widget.ListView.measureHeightOfChildren(ListView.java:1270)
02-07 17:09:59.938: E/AndroidRuntime(25817):    at android.widget.ListView.onMeasure(ListView.java:1182)
02-07 17:09:59.938: E/AndroidRuntime(25817):    at android.view.View.measure(View.java:17430)
02-07 17:09:59.938: E/AndroidRuntime(25817):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)

请告知。

无法将值传递给android中的详细片段

0 个答案: