Viewpager片段中的Textview無法正確更新

Question

我創建了一個布局，並根據收到的數據動態添加標簽。 我對片段進行了相同的動態更新文本視圖。 盡管在加載布局時並且如果我在片段或視圖分頁器中滑動（對不起，我是所有新手，希望我的術語是正確的），它們的更新就可以了（這意味着更新某些問題有時會滯后），並且正確數據。 但是，如果我重新打開布局，然后單擊選項卡以更改片段，我將沒有數據或錯誤數據。 示例：-第一次加載Layout時，我的第一個和第三個選項卡可以正常加載。 如果我單擊第二個選項卡（一直不滑動，而是一直觸摸頂部的選項卡），則第二個選項卡的片段中沒有任何數據。 在四處移動時，會隨機選擇選項卡，第一個選項卡會加載第二個選項卡數據，但是第二個選項卡從不加載任何內容。 當我加載新頁面或第一次加載頁面時，刷卡的方式不一樣。 讓我知道我在哪里做錯了。 謝謝。

這是我的代碼：

布局文件-show_score.xml

<android.support.design.widget.CoordinatorLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.lp.activity.ShowScorePassagesActivity">
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@drawable/children_school"
        android:scaleType="centerCrop"
        android:alpha="0.5"
        android:layout_below="@+id/appBackBar"/>

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingTop="@dimen/appbar_padding_top"
        android:theme="@style/AppTheme.AppBarOverlay">

        <include android:id="@+id/appBackBar"
            layout="@layout/detail_appbar"/>

        <android.support.design.widget.TabLayout
            android:id="@+id/passagetabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

        </android.support.design.widget.TabLayout>
    </android.support.design.widget.AppBarLayout>

    <android.support.v4.view.ViewPager
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>

片段文件-fragment_show_score_passage.xml

   <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/constraintLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.lp.activity.ShowScorePassagesActivity$PlaceholderFragment">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <!-- TODO: Update blank fragment layout -->
        <android.support.v7.widget.CardView
            android:id="@+id/cardView4"
            android:layout_width="match_parent"
            android:layout_height="200dp"
            app:cardElevation="5dp"
            android:scaleType="fitXY"
            android:layout_margin="5dp">
            <ScrollView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                style="@style/scrollbar_shape_style">
                <TextView
                    android:id="@+id/showScore"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:textSize="18dp"
                    android:scaleType="fitXY"
                    android:text="TextView"
                    android:autoLink="web"
                    android:linksClickable="true"
                    android:padding="20dp"
                    android:clipToPadding="false"/>
            </ScrollView>
        </android.support.v7.widget.CardView>

        <android.support.v7.widget.CardView
            android:id="@+id/cardView5"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:cardElevation="5dp"
            android:layout_below="@+id/cardView4"
            android:layout_marginLeft="5dp"
            android:layout_marginRight="5dp"
            android:layout_marginTop="5dp">
            <ScrollView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                style="@style/scrollbar_shape_style">
                <GridView
                    android:id="@+id/fluencyAudioGrid"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:numColumns="auto_fit"
                    android:horizontalSpacing="2dp"
                    android:verticalSpacing="5dp"
                    android:columnWidth="120dp"
                    android:paddingTop="10dp"
                    android:paddingBottom="10dp"
                    android:clipToPadding="false"
                    android:stretchMode="spacingWidthUniform"
                    layout="@layout/icons_for_dashboard"
                    android:scrollbarThumbVertical="@drawable/scroolbar_style"
          android:scrollbarTrackVertical="@drawable/scroolbar_style_background">
                </GridView>
            </ScrollView>
        </android.support.v7.widget.CardView>
    </RelativeLayout>

</android.support.constraint.ConstraintLayout>

魔術發生的主要Java文件-ShowScorePassageActivity.java

    public class ShowScorePassagesActivity extends AppCompatActivity {

    private SectionsPagerAdapter mSectionsPagerAdapter;
    private ViewPager mViewPager;
    public GridView gridView;
    public ArrayList<String> gridItems = new ArrayList<String>();
    public static TextView fragTextView;
    static String fragNewTextView = "";
    public static ArrayList<String> fluencyMarksList = new ArrayList<>();
    public TabLayout tabLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.show_score_passages);

        Intent in = getIntent();
        String intentData = in.getStringExtra("intentData");
        String fluencyMarks = in.getStringExtra("fluencyMarks");
        tabLayout = (TabLayout) findViewById(R.id.passagetabs);
        String mFluencyMarkList []= fluencyMarks.split("@");
        fluencyMarksList = new ArrayList<String>(Arrays.asList(mFluencyMarkList));
        int count = 1;
        int counts=fluencyMarksList.size();
        for(int i = 0; i < counts; i++){
            tabLayout.addTab(tabLayout.newTab().setText("Passage "+count));
            count=count+1;
        }
        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
        mViewPager = (ViewPager) findViewById(R.id.container);
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager(), tabLayout.getTabCount());
        mViewPager.setAdapter(mSectionsPagerAdapter);
        mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                mViewPager.setCurrentItem(tab.getPosition());
                int position =  tab.getPosition();
                if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) {
                    if (position ==0){
                        fragTextView.setText(Html.fromHtml(fluencyMarksList.get(0), Html.FROM_HTML_MODE_COMPACT));
                    }
                    else if (position ==1){
                        fragTextView.setText(Html.fromHtml(fluencyMarksList.get(1) , Html.FROM_HTML_MODE_COMPACT));
                    }
                    else if (position ==2){
                        fragTextView.setText(Html.fromHtml(fluencyMarksList.get(2) , Html.FROM_HTML_MODE_COMPACT));
                    }
                } else {
                    if (position ==0){
                        fragTextView.setText(Html.fromHtml(fluencyMarksList.get(0)));
                    }
                    else if (position ==1){
                        fragTextView.setText(Html.fromHtml(fluencyMarksList.get(1)));
                    }
                    else if (position ==2){
                        fragTextView.setText(Html.fromHtml(fluencyMarksList.get(2)));
                    }
                }
            }
            @Override
            public void onTabUnselected(TabLayout.Tab tab) {
                fragTextView.setText("");
            }
            @Override
            public void onTabReselected(TabLayout.Tab tab) {
            }
        });
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_show_score_passages, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";

        public PlaceholderFragment() {
        }

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }
        @RequiresApi(api = Build.VERSION_CODES.N)
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_show_score_passages, container, false);
            fragTextView = (TextView) rootView.findViewById(R.id.showScore);
            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) {

                fragTextView.setText(Html.fromHtml(fluencyMarksList.get(0) , Html.FROM_HTML_MODE_COMPACT));
            } else {

                fragTextView.setText(Html.fromHtml(fluencyMarksList.get(0)));
            }
            return rootView;
        }
        @Override
        public void onActivityCreated(Bundle savedInstanceState) {
            super.onActivityCreated(savedInstanceState);
        }
    }
    public class SectionsPagerAdapter extends FragmentPagerAdapter {
        int mNumOfTabs;
        Fragment fragment = null;

        public SectionsPagerAdapter(FragmentManager fm, int NumOfTabs) {
            super(fm);
            this.mNumOfTabs=NumOfTabs;

        }

        @Override
        public Fragment getItem(int position) {
            return PlaceholderFragment.newInstance(position + 1);
        }

        @Override
        public int getCount() {
            return mNumOfTabs;
        }
    }
}

Answer 1

這是我所做的：

這只是對我有用的一個例子，希望對您有所幫助

在OnCreate ：

ViewPager mViewPager = (ViewPager) findViewById(R.id.container);
this.addPages(mViewPager);
mViewPager.setOffscreenPageLimit(3);

TabLayout tabLayout = (TabLayout) findViewById(R.id.mTab_ID);
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
tabLayout.setupWithViewPager(mViewPager);
tabLayout.addOnTabSelectedListener(listener(mViewPager));

然后通過執行以下操作將片段添加到TabLayout ：

//ADD ALL PAGES TO TABLAYOUT
private void addPages(ViewPager pager) {
    adapter = new MyFragPagerAdapter(getSupportFragmentManager());
    adapter.addPage(new FragmentAdapter1());
    adapter.addPage(new FragmentAdapter2());
    adapter.addPage(new FragmentAdapter3());

    //SET ADAPTER TO PAGER
    pager.setAdapter(adapter);
}

然后通過執行TabLayout OnTabSelectedListener來實現TabLayout單擊事件OnTabSelectedListener ：

//TabLayout Click Events
private TabLayout.OnTabSelectedListener listener(final ViewPager pager) {
    return new TabLayout.OnTabSelectedListener() {
        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            pager.setCurrentItem(tab.getPosition());
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {

        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {

        }
    };
}