ViewPager showing fragments with the same data when should be treating each fragment individually

Question

I am a relative newbie to android programming and I am having some issues. I'm am trying to attach fragments to a view pager for a todo application. I have 7 fragments that repersent each day. Each fragment loads correctly, but when I add a task, it shows across all fragments instead of only the one I entered the task in. Code is below. Any help would be great, thank you!

ViewPager Activity

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

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;

import com.parse.Parse;
import com.parse.ParseObject;
import com.parse.ParseUser;

public class ToDoActivity extends FragmentActivity {
    MyPageAdapter pageAdapter;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_page_view);

        Parse.initialize(this, "uD7", "BrZkpvhY6Asi5oSq");
        //ParseAnalytics.trackAppOpened(getIntent());
        ParseObject.registerSubclass(Task.class);

        ParseUser currentUser = ParseUser.getCurrentUser();
        if(currentUser == null){
            Intent intent = new Intent(this, LoginActivity.class);
            startActivity(intent);
            finish();
        }

        List<Fragment> fragments = getFragments();

        pageAdapter = new MyPageAdapter(getSupportFragmentManager(), fragments);

        ViewPager pager = (ViewPager)findViewById(R.id.viewpager);
        pager.setAdapter(pageAdapter);

    }

    private List<Fragment> getFragments(){
        List<Fragment> fList = new ArrayList<Fragment>();

        fList.add(ToDoListFragment.newInstance("Important And Urgent"));
        fList.add(ToDoListFragment.newInstance("Important Not Urgent"));
        fList.add(ToDoListFragment.newInstance("Not Important But Urgent"));

        return fList;
    }

    private class MyPageAdapter extends FragmentPagerAdapter {
        private List<Fragment> fragments;

        public MyPageAdapter(FragmentManager fm, List<Fragment> fragments) {
            super(fm);
            this.fragments = fragments;
        }
        @Override
        public Fragment getItem(int position) {
            return this.fragments.get(position);
        }

        @Override
        public int getCount() {
            return this.fragments.size();
        }
    }
}

FragmentActivity.java

    public class ToDoListFragment extends Fragment implements AdapterView.OnItemClickListener {

    public static final String EXTRA_MESSAGE = "EXTRA_MESSAGE";
    private EditText mTaskInput;
    private ListView mListView;
    private TaskAdapter mAdapter = null;
    private Button mButton;

    public static final ToDoListFragment newInstance(String message)
    {
        ToDoListFragment f = new ToDoListFragment();
        Bundle bdl = new Bundle(1);
        bdl.putString(EXTRA_MESSAGE, message);
        f.setArguments(bdl);
        return f;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
        Bundle savedInstanceState) {
        String message = getArguments().getString(EXTRA_MESSAGE);
        View v = inflater.inflate(R.layout.important_urgent, container, false);
        TextView messageTextView = (TextView)v.findViewById(R.id.textView);
        messageTextView.setText(message);

        mAdapter = new TaskAdapter(getActivity(), new ArrayList<Task>());

        mTaskInput = (EditText) v.findViewById(R.id.task_input);
        mListView = (ListView) v.findViewById(R.id.task_list);
        mButton = (Button) v.findViewById(R.id.submit_button);
        mListView.setAdapter(mAdapter);
        mListView.setOnItemClickListener(this);
        mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (mTaskInput.getText().length() > 0){
                    Task t = new Task();
                    t.setACL(new ParseACL(ParseUser.getCurrentUser()));
                    t.setUser(ParseUser.getCurrentUser());
                    t.setDescription(mTaskInput.getText().toString());
                    t.setCompleted(false);
                    t.saveEventually();
                    mAdapter.insert(t, 0);
                    mTaskInput.setText("");
                }
            }
        });

        updateData();

        return v;
    }

    public void updateData(){
        ParseQuery<Task> query = ParseQuery.getQuery(Task.class);
        query.whereEqualTo("user", ParseUser.getCurrentUser());
        query.setCachePolicy(ParseQuery.CachePolicy.CACHE_THEN_NETWORK);
        query.findInBackground(new FindCallback<Task>() {
            @Override
            public void done(List<Task> tasks, ParseException error) {
                if(tasks != null){
                    mAdapter.clear();
                    for (int i = 0; i < tasks.size(); i++) {
                        mAdapter.add(tasks.get(i));
                    }
                }
            }
        });
    }

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
        Task task = mAdapter.getItem(position);
        TextView taskDescription = (TextView) view.findViewById(R.id.task_description);

        task.setCompleted(!task.isCompleted());

        if(task.isCompleted()){
            taskDescription.setPaintFlags(taskDescription.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
        }else{
            taskDescription.setPaintFlags(taskDescription.getPaintFlags() & (~Paint.STRIKE_THRU_TEXT_FLAG));
        }

        task.saveEventually();
    }
}

FragmentXML

   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin" >

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="25dp"
        android:text="Hello"
        android:layout_gravity="center"
        android:id="@+id/textView"
        android:paddingTop="10dp"
        android:paddingBottom="10dp"
        android:background="@color/red"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <EditText
            android:id="@+id/task_input"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="text"
            android:hint="Enter a Task">
            <requestFocus />
        </EditText>

        <Button
            android:id="@+id/submit_button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Submit" />
    </LinearLayout>

    <ListView
        android:id="@+id/task_list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

Answer 1

If you are using the same fragment XML file for each fragment, then when you update one, you are going to update all of them. You would need to create 7 different XML layouts (they could be the same layout, but would need different identifiers), and update that fragment layout individually.

Fragments are basically individual activities, running in a single Activity. You can reuse Fragments in different Activities, but each Fragment should have it's own layout.