Question

我正在尝试将评级栏实现为我拥有的片段类。但我总是得到一个零点异常并崩溃我的应用程序。我阅读的教程都展示了如何在Activity类中实现评级栏。我怎样才能在片段类中实现它？

我的班级

package com.f%%%%%%%%;

import java.util.ArrayList;
...................

public class TheaterDetailFragment extends Fragment {

    private ViewPager viewtheater;
    private ViewPageAdapter adaptertheater;
    private Activity activity;
    private CommonVariable commonVariable;
    private ProgressDialog dialog;
    private ArrayList<BaseElement> TheaterDetail;
    private ArrayList<BaseElement> theateritems;
    private int id;
    private String pos;
    private RatingBar ratingBar;
    private TextView txtRatingValue; 

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

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

        addListenerOnRatingBar();

        activity = this.getActivity();

        pos= getArguments().getString(BundleKey.THEATERPOSITION.getKey());

        commonVariable = (CommonVariable) activity.getApplication();

        viewtheater = (ViewPager) view.findViewById(R.id.theaterdetail);

        dialog = new ProgressDialog(TheaterDetailFragment.this.getActivity());
        dialog.setMessage("Loading Theater Details");
        dialog.setCancelable(true);

        new BackGround().execute();

        return view;
    }

     public void addListenerOnRatingBar() {

            ratingBar = (RatingBar) getView().findViewById(R.id.ratingBar1);
            txtRatingValue = (TextView) getView().findViewById(R.id.txtRatingValue);

            //if rating value is changed,
            //display the current rating value in the result (textview) automatically
            ratingBar.setOnRatingBarChangeListener(new OnRatingBarChangeListener() {
                public void onRatingChanged(RatingBar ratingBar, float rating,
                    boolean fromUser) {

                    txtRatingValue.setText(String.valueOf(rating));

                }
            });
          }

    public class BackGround extends AsyncTask<Void, Void, Void> {

        @Override
        protected Void doInBackground(Void... params) {

            //Theater theaterdetail = (Theater) commonVariable.getTheater().get(id);

            TheaterDetail = JSONServices.getTheaterDetails(pos);

            return null;
        }

        @Override
        // check again
        protected void onPostExecute(Void result) {


            commonVariable.setTheaterDetail(TheaterDetail);

            adaptertheater = new ViewPageAdapter(commonVariable.getTheaterDetail(),
                    Element.THEATER_DETAIL.getType(), activity);

            viewtheater.setAdapter(adaptertheater);


            dialog.dismiss();



            super.onPostExecute(result);

        }

        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub

            dialog.show();
            super.onPreExecute();

        }

    }

}

我的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:id="@+id/filmhall"
    android:background="@color/grey" >

    <!--
      <fragment 
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
    -->


   <TextView
        android:id="@+id/id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="#000000"
        android:layout_marginTop="4dp"
        android:textStyle="bold"
        android:textSize="15dp" />


   <RatingBar
        android:id="@+id/ratingBar1"
        style="?android:attr/ratingBarStyleSmall"
        android:isIndicator="false"
        android:layout_marginTop="10dp"
        android:layout_marginLeft="4dp"
        android:numStars="10"
        android:rating="2.0"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />

     <TextView

            android:id="@+id/txtRatingValue"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="4dp"
            android:text="Rating :"
            android:textAppearance="?android:attr/textAppearanceSmall" />

    </LinearLayout>

*其他字段已删除！

我提到的教程

http://www.mkyong.com/android/android-rating-bar-example/

1.最初在findviewbyid有一个错误，我使用getview（）修复它。

提前致谢！

UPDATE !!

logcat的

12-30 12:01:23.456: E/AndroidRuntime(13134): FATAL EXCEPTION: main
12-30 12:01:23.456: E/AndroidRuntime(13134): java.lang.NullPointerException
12-30 12:01:23.456: E/AndroidRuntime(13134):    at com.fortuna.cinemalk.TheaterDetailFragment.addListenerOnRatingBar(TheaterDetailFragment.java:119)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at com.fortuna.cinemalk.TheaterDetailFragment.onCreateView(TheaterDetailFragment.java:98)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.support.v4.app.Fragment.performCreateView(Fragment.java:1460)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:911)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:429)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.os.Handler.handleCallback(Handler.java:587)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.os.Handler.dispatchMessage(Handler.java:92)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.os.Looper.loop(Looper.java:123)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at android.app.ActivityThread.main(ActivityThread.java:4627)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at java.lang.reflect.Method.invokeNative(Native Method)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at java.lang.reflect.Method.invoke(Method.java:521)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
12-30 12:01:23.456: E/AndroidRuntime(13134):    at dalvik.system.NativeStart.main(Native Method)

LOGCAT for MD's和REDDY的答案

12-30 12:17:26.023: E/AndroidRuntime(13545): FATAL EXCEPTION: main
12-30 12:17:26.023: E/AndroidRuntime(13545): java.lang.NullPointerException
12-30 12:17:26.023: E/AndroidRuntime(13545):    at com.fortuna.cinemalk.TheaterDetailFragment.addListenerOnRatingBar(TheaterDetailFragment.java:126)
12-30 12:17:26.023: E/AndroidRuntime(13545):    at com.fortuna.cinemalk.TheaterDetailFragment.onCreateView(TheaterDetailFragment.java:100)
12-30 12:17:26.023: E/AndroidRuntime(13545):    at android.support.v4.app.Fragment.performCreateView(Fragment.java:1460)
12-30 12:17:26.023: E/AndroidRuntime(13545):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:911)

Answer 1

尝试以RootView作为参数传递给addListenerOnRatingBar(....)

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

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

    addListenerOnRatingBar(view);
    ........
  }

并像这样实施addListenerOnRatingBar(....)。

 public void addListenerOnRatingBar(View v) {

        ratingBar = (RatingBar) v.findViewById(R.id.ratingBar1);
        txtRatingValue = (TextView) v.findViewById(R.id.txtRatingValue);

        //if rating value is changed,
        //display the current rating value in the result (textview) automatically
        ratingBar.setOnRatingBarChangeListener(new OnRatingBarChangeListener() {
            public void onRatingChanged(RatingBar ratingBar, float rating,
                boolean fromUser) {

                txtRatingValue.setText(String.valueOf(rating));

            }
        });
      }

Answer 2

更新此代码

 ratingBar = (RatingBar) getView().findViewById(R.id.ratingBar1);
 txtRatingValue = (TextView) getView().findViewById(R.id.txtRatingValue);

像这样并将其保留在onCreateView()中或将该视图传递给该方法以供使用。

public void addListenerOnRatingBar(View view) {
    ratingBar = (RatingBar) view.findViewById(R.id.ratingBar1);
    txtRatingValue = (TextView) view.findViewById(R.id.txtRatingValue);
}

和来自onCreateView（）的调用方法，如addListenerOnRatingBar(view);

在片段类中实现评级栏的问题

2 个答案: