java - NullPointerException - fragment

Question

在尝试运行我的应用程序时，我收到了来自 logcat 的以下消息。本质上，我试图使用查询从解析中检索信息列表。代码看起来不错，所以我不太确定如何解决这个问题。

Logcat消息

08-24 19:23:35.387: E/AndroidRuntime(3996): FATAL EXCEPTION: main
    08-24 19:23:35.387: E/AndroidRuntime(3996): Process: com.dooba.beta, PID: 3996
    08-24 19:23:35.387: E/AndroidRuntime(3996): java.lang.NullPointerException
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at com.dooba.beta.Fragment1$2.done(Fragment1.java:154)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at com.parse.FindCallback.internalDone(FindCallback.java:45)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at com.parse.FindCallback.internalDone(FindCallback.java:1)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at com.parse.Parse$6$1.run(Parse.java:888)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at android.os.Handler.handleCallback(Handler.java:733)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at android.os.Handler.dispatchMessage(Handler.java:95)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at android.os.Looper.loop(Looper.java:136)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at android.app.ActivityThread.main(ActivityThread.java:5017)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at java.lang.reflect.Method.invokeNative(Native Method)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at java.lang.reflect.Method.invoke(Method.java:515)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    08-24 19:23:35.387: E/AndroidRuntime(3996):     at dalvik.system.NativeStart.main(Native Method)

代码

public class Fragment1 extends Fragment {

    public interface Constants {
        String LOG = "com.dooba.beta";
    }

    private String currentUserId;
    private String currentUser;

    protected TextView mUserRetrieved;
    protected TextView mUserActivityNameRetrieved;
    protected TextView mUserNameRetrieved;




    private ArrayAdapter<String> namesArrayAdapter;
    private ArrayList<String> names;
    private ArrayList<String> age;
    private ArrayList<String> headline;
    private ArrayList<String> activityname;

    private ArrayList<Images> alProfilePicture;
    private ListView usersListName;
    private ListView usersListHeadline;
    private ListView usersListActivityname;

    private Button logoutButton;
    String userGender = ParseUser.getCurrentUser().getString("Gender");

    String activityName = ParseUser.getCurrentUser().getString("ActivityName");
    Number maxDistance = ParseUser.getCurrentUser().getNumber(
            "Maximum_Distance");
    String userLookingGender = ParseUser.getCurrentUser().getString(
            "Looking_Gender");
    Number minimumAge = ParseUser.getCurrentUser().getNumber("Minimum_Age");
    Number maximumAge = ParseUser.getCurrentUser().getNumber("Maximum_Age");
    Number userage = ParseUser.getCurrentUser().getNumber("Age");

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        setConversationsList();

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment1_layout, container,
                false);

        mUserRetrieved = (TextView) getActivity().findViewById(R.id.userlistname);


        Button newPage = (Button)view.findViewById(R.id.btnMatchConfirm);
        newPage.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                ParseUser currentUser = ParseUser.getCurrentUser();

                currentUser.put("UserMatchName", mUserRetrieved);
                Intent intent = new Intent(getActivity(), matchOptionActivity.class);
                startActivity(intent);
            }
        });


        return view;
    }

    private void setConversationsList() {
        currentUserId = ParseUser.getCurrentUser().getObjectId();
        names = new ArrayList<String>();
        age = new ArrayList<String>();
        headline = new ArrayList<String>();
        activityname = new ArrayList<String>();

        alProfilePicture = new ArrayList<Images>();

        ParseQuery<ParseUser> query = ParseUser.getQuery();
        ParseQuery<ParseUser> query2 = ParseUser.getQuery();
        ParseQuery<ParseUser> query3 = ParseUser.getQuery();
        ParseQuery<ParseUser> query4 = ParseUser.getQuery();
        ParseQuery<ParseUser> query5 = ParseUser.getQuery();

        query.findInBackground(new FindCallback<ParseUser>() {

            @Override
            public void done(List<ParseUser> objects,ParseException e) {

                for(int i=0;i<objects.size();i++){
                    // Do whatever you need to extract object from "users"
                    ParseQuery<ParseObject> query = ParseQuery.getQuery("User");
                    query.whereNotEqualTo("objectId", ParseUser.getCurrentUser()
                            .getObjectId());
                    // users with Gender = currentUser.Looking_Gender
                    query.whereEqualTo("Gender", userLookingGender);
                    // users with Looking_Gender = currentUser.Gender
                    query.whereEqualTo("Looking_Gender", userGender);
                    query.setLimit(1);
                    query.whereEqualTo("ActivityName", activityName);
                    // query.whereGreaterThanOrEqualTo("Age", minimumAge);
                    // query.whereLessThanOrEqualTo("Age", maximumAge);

                    mUserActivityNameRetrieved = (TextView) getActivity().findViewById(R.id.userlistactivityname);

                    mUserActivityNameRetrieved.setText(objects.get(i).get("ActivityName").toString()); 



                }
    }//for loop
            });

        query2.findInBackground(new FindCallback<ParseUser>() {

            @Override
            public void done(List<ParseUser> objects,ParseException e) {

                for(int i=0;i<objects.size();i++){
                    // Do whatever you need to extract object from "users"
                    ParseQuery<ParseObject> query2 = ParseQuery.getQuery("User");
                    query2.whereNotEqualTo("objectId", ParseUser.getCurrentUser()
                            .getObjectId());
                    // users with Gender = currentUser.Looking_Gender
                    query2.whereEqualTo("Gender", userLookingGender);
                    // users with Looking_Gender = currentUser.Gender
                    query2.whereEqualTo("Looking_Gender", userGender);
                    query2.setLimit(1);
                    query2.whereEqualTo("ActivityName", activityName);
                    // query.whereGreaterThanOrEqualTo("Age", minimumAge);
                    // query.whereLessThanOrEqualTo("Age", maximumAge);

                    mUserNameRetrieved = (TextView) getActivity().findViewById(R.id.userlistname);

                    mUserNameRetrieved.setText(objects.get(i).get("Name").toString()); 



                }
    }//for loop
            });

        query3.findInBackground(new FindCallback<ParseUser>() {

            @Override
            public void done(List<ParseUser> objects,ParseException e) {

                for(int i=0;i<objects.size();i++){
                    // Do whatever you need to extract object from "users"
                    ParseQuery<ParseObject> query3 = ParseQuery.getQuery("User");
                    query3.whereNotEqualTo("objectId", ParseUser.getCurrentUser()
                            .getObjectId());
                    // users with Gender = currentUser.Looking_Gender
                    query3.whereEqualTo("Gender", userLookingGender);
                    // users with Looking_Gender = currentUser.Gender
                    query3.whereEqualTo("Looking_Gender", userGender);
                    query3.setLimit(1);
                    query3.whereEqualTo("ActivityName", activityName);
                    // query.whereGreaterThanOrEqualTo("Age", minimumAge);
                    // query.whereLessThanOrEqualTo("Age", maximumAge);

                    mUserNameRetrieved = (TextView) getActivity().findViewById(R.id.userlistage);

                    mUserNameRetrieved.setText(objects.get(i).get("Name").toString()); 



                }
    }//for loop
            });

        query4.findInBackground(new FindCallback<ParseUser>() {

            @Override
            public void done(List<ParseUser> objects,ParseException e) {

                for(int i=0;i<objects.size();i++){
                    // Do whatever you need to extract object from "users"
                    ParseQuery<ParseObject> query4 = ParseQuery.getQuery("User");
                    query4.whereNotEqualTo("objectId", ParseUser.getCurrentUser()
                            .getObjectId());
                    // users with Gender = currentUser.Looking_Gender
                    query4.whereEqualTo("Gender", userLookingGender);
                    // users with Looking_Gender = currentUser.Gender
                    query4.whereEqualTo("Looking_Gender", userGender);
                    query4.setLimit(1);
                    query4.whereEqualTo("ActivityName", activityName);
                    // query.whereGreaterThanOrEqualTo("Age", minimumAge);
                    // query.whereLessThanOrEqualTo("Age", maximumAge);

                    mUserNameRetrieved = (TextView) getActivity().findViewById(R.id.userlistheadline);

                    mUserNameRetrieved.setText(objects.get(i).get("Headline").toString()); 



                }
    }//for loop
            });







        query5.findInBackground(new FindCallback<ParseUser>() {

            @Override
            public void done(List<ParseUser> objects,ParseException e) {

                for(int i=0;i<objects.size();i++){
                    // Do whatever you need to extract object from "users"
                    ParseQuery<ParseObject> query5 = ParseQuery.getQuery("User");
                    query5.whereNotEqualTo("objectId", ParseUser.getCurrentUser()
                            .getObjectId());
                    // users with Gender = currentUser.Looking_Gender
                    query5.whereEqualTo("Gender", userLookingGender);
                    // users with Looking_Gender = currentUser.Gender
                    query5.whereEqualTo("Looking_Gender", userGender);
                    query5.setLimit(1);
                    query5.whereEqualTo("ActivityName", activityName);
                    // query.whereGreaterThanOrEqualTo("Age", minimumAge);
                    // query.whereLessThanOrEqualTo("Age", maximumAge);

                    ParseFile image = objects.get(i).getParseFile("ProfilePicture");


                    ParseImageView imageView = (ParseImageView) getView().findViewById(R.id.profilePictureresult);

                     // The placeholder will be used before and during the fetch, to be replaced by the fetched image
                     // data.
                     imageView.setPlaceholder(getResources().getDrawable(R.drawable.profile_pict));
                     imageView.setParseFile(image);
                     imageView.loadInBackground(new GetDataCallback() {
                       @Override
                       public void done(byte[] data, ParseException e) {
                           if (data != null) {
                               Log.i("ParseImageView", "Fetched: " + data.length);
                             } else {
                               Log.e("ParseImageView", "Error fetching: " + e.getMessage());
                             }
                       }


                 });
                }
    }//for loop
            });

    }


    public void openConversation(ArrayList<String> names, int pos) {
        ParseQuery<ParseUser> query = ParseUser.getQuery();
        query.whereEqualTo("Name", names.get(pos));
        query.findInBackground(new FindCallback<ParseUser>() {
            public void done(List<ParseUser> user, ParseException e) {
                if (e == null) {
                    Intent intent = new Intent(getActivity()
                            .getApplicationContext(), MessagingActivity.class);
                    intent.putExtra("RECIPIENT_ID", user.get(0).getObjectId());
                    startActivity(intent);
                } else {
                    Toast.makeText(getActivity().getApplicationContext(),
                            "Error finding that user", Toast.LENGTH_SHORT)
                            .show();
                }
            }
        });
    }

}

XML 布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/blue_bac3"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/imageView2"
        android:layout_width="70dp"
        android:layout_height="50dp"
        android:layout_alignParentRight="true"
        android:layout_alignTop="@+id/profilePictureresult"
        android:layout_marginTop="16dp"
        android:alpha="0.7"
        android:src="@drawable/left_right" />

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="70dp"
        android:layout_height="50dp"
        android:layout_alignParentLeft="true"
        android:layout_alignTop="@+id/imageView2"
        android:alpha="0.7"
        android:src="@drawable/left_arrow2" />

    <TextView
        android:id="@+id/userlistactivityname"
       android:textColor="#ADD8E6"
    android:padding="6dp"
    android:gravity="center"
    android:textStyle="bold"
    android:typeface="serif"
    android:layout_below="@+id/tactivityname"
            android:layout_centerHorizontal="true"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="18sp" >
    </TextView>

    <TextView
        android:id="@+id/userlistage"
        android:layout_width="80dp"
        android:layout_height="50dp"
        android:layout_below="@+id/profilePictureresult"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="9dp"
        android:divider="@null" >
    </TextView>

    <TextView
        android:id="@+id/tactivityname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/userlistage"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="7dp"
        android:text="Activity Name"
        android:textColor="#d2f2a2"
        android:textSize="23sp"
        android:textStyle="bold" />

    <com.parse.ParseImageView
        android:id="@+id/profilePictureresult"
        android:layout_width="132dp"
        android:layout_height="120dp"
        android:layout_below="@+id/userlistheadline"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="4dp"
        android:alpha="1"
        android:background="@drawable/border_image"
        android:cropToPadding="true"
        android:padding="3dp"
        android:scaleType="centerCrop" />

    <TextView
        android:id="@+id/userlistheadline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
     android:layout_below="@+id/userlistname"
            android:layout_centerHorizontal="true"
        android:gravity="center"
        android:padding="6dp"
        android:textColor="#ffffff"
        android:textSize="18sp"
        android:textStyle="bold"
        android:typeface="serif" />

    <TextView
        android:id="@+id/userlistname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/userlistheadline"
        android:layout_alignParentTop="true"
        android:layout_marginTop="25dp"
        android:gravity="center"
        android:padding="6dp"
        android:textColor="#ADD8E6"
        android:textSize="22sp"
        android:textStyle="bold"
        android:typeface="serif" />

    <Button
        android:id="@+id/btnMatchConfirm"
        android:layout_width="100dp"
        android:layout_height="50dp"
        android:layout_below="@+id/userlistactivityname"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="18dp"
        android:alpha="0.7"
        android:background="#ADD8E6"
        android:text="Confirm"
        android:textColor="#000000"
        android:textSize="22sp"
        android:typeface="serif" />

</RelativeLayout>

提前致谢

Answer 1

在每个 done() 回调中，您正在执行以下操作:

mUserNameRetrieved = (TextView) getActivity().findViewById(R.id.userlistage);

这将在您的 Activity 中搜索 id userlistage。
但是，这个 id 位于您的 Fragment 中，而不是您的 Activity 中。
改为这样做:

mUserNameRetrieved = (TextView) getView().findViewById(R.id.userlistage);

如果您的 fragment 在任务期间被破坏，请小心。