AppCompatActivityのフラグメント

Question

スワイプビューアクティビティでフラグメントを使用する場合は、この拡張機能を使用できますか？

public class Overview_Screen extends AppCompatActivity { 

マイフラグメントのクラスは、このいずれかを使用します。ここでは

public class MessagesFragmentPortrait extends android.support.v4.app.Fragment { 

私のアプリがクラッシュし続けるので、私はこれを求めています...
は私の主な活動です：

public class Overview_Screen extends AppCompatActivity { 

    private SectionsPagerAdapter mSectionsPagerAdapter; 

    private ViewPager mViewPager; 

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

     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager()); 
     mViewPager = (ViewPager) findViewById(R.id.container); 
     mViewPager.setAdapter(mSectionsPagerAdapter); 

     TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs); 
     tabLayout.setupWithViewPager(mViewPager); 

    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     getMenuInflater().inflate(R.menu.menu_overview_screen, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     int id = item.getItemId(); 

     if (id == R.id.action_settings) { 
      Intent settings_intent = new Intent(this, Settings_Screen.class); 
      startActivity(settings_intent); 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 

    public static class SectionsPagerAdapter extends FragmentPagerAdapter { 

     public SectionsPagerAdapter(FragmentManager fm) { 
      super(fm); 
     } 

     @Override 
     public Fragment getItem(int i) { 
      switch (i) { 
       case 0: 
        return new AccountFragmentPortrait(); 
       case 1: 
        return new FeedFragmentPortrait(); 
       default: 
        return new MessagesFragmentPortrait(); 
      } 
     } 

     @Override 
     public int getCount() { 
      return 3; 
     } 

     @Override 
     public CharSequence getPageTitle(int position) { 
      switch (position) { 
       case 0: 
        return "Account"; 
       case 1: 
        return "Feed"; 
       case 2: 
        return "Messages"; 
      } 
      return null; 
     } 
    } 
} 

、ここで私のスタックトレースです：

FATAL EXCEPTION: main 
    Process: de.lukas_schroederoutlook.connect, PID: 3364 
    java.lang.RuntimeException: Unable to start activity ComponentInfo{de.lukas_schroederoutlook.connect/de.lukas_schroederoutlook.connect.Overview_Screen}: 
    android.view.InflateException: Binary XML file line #41: Binary XML file line #41: Error inflating class fragment 
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2665) 
     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 
     at android.app.ActivityThread.-wrap12(ActivityThread.java) 
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 
     at android.os.Handler.dispatchMessage(Handler.java:102) 
     at android.os.Looper.loop(Looper.java:154) 
     at android.app.ActivityThread.main(ActivityThread.java:6119) 
     at java.lang.reflect.Method.invoke(Native Method) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 
    Caused by: android.view.InflateException: Binary XML file line #41: Binary XML file line #41: Error inflating class fragment 
    Caused by: android.view.InflateException: Binary XML file line #41: Error inflating class fragment 
    Caused by: java.lang.NullPointerException 
     at java.lang.VMClassLoader.findLoadedClass(Native Method) 
     at java.lang.ClassLoader.findLoadedClass(ClassLoader.java:742) 
     at java.lang.ClassLoader.loadClass(ClassLoader.java:362) 
     at java.lang.ClassLoader.loadClass(ClassLoader.java:312) 
     at android.support.v4.app.Fragment.isSupportFragmentClass(Fragment.java:469) 
     at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2384) 
     at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120) 
     at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:378) 
     at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:33) 
     at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:77) 
     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:777) 
     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727) 
     at android.view.LayoutInflater.rInflate(LayoutInflater.java:858) 
     at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821) 
     at android.view.LayoutInflater.inflate(LayoutInflater.java:518) 
     at android.view.LayoutInflater.inflate(LayoutInflater.java:426) 
     at android.view.LayoutInflater.inflate(LayoutInflater.java:377) 
     at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:284) 
     at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:143) 
     at de.lukas_schroederoutlook.connect.Overview_Screen.onCreate(Overview_Screen.java:42) 
     at android.app.Activity.performCreate(Activity.java:6679) 
     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118) 
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2618) 
     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 
     at android.app.ActivityThread.-wrap12(ActivityThread.java) 
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 
     at android.os.Handler.dispatchMessage(Handler.java:102) 
     at android.os.Looper.loop(Looper.java:154) 
     at android.app.ActivityThread.main(ActivityThread.java:6119) 
     at java.lang.reflect.Method.invoke(Native Method) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

そして最後に、ここに私の概要画面xmlです：

<?xml version="1.0" encoding="utf-8"?> 
<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="de.lukas_schroederoutlook.connect.Overview_Screen"> 

<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"> 

    <android.support.v7.widget.Toolbar 
     android:id="@+id/toolbar" 
     android:layout_width="match_parent" 
     android:layout_height="?attr/actionBarSize" 
     android:background="?attr/colorPrimary" 
     app:layout_scrollFlags="scroll|enterAlways" 
     app:popupTheme="@style/AppTheme.PopupOverlay"> 

    </android.support.v7.widget.Toolbar> 

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

</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" /> 

<fragment 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:id="@+id/feed_fragment_portrait"/> 

<fragment 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:id="@+id/feed_fragment_landscape"/> 

そして、私の概要画面のフラグメントのxml：あなたはあなたの中にclass属性を指定する必要が

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin" 
android:paddingLeft="@dimen/activity_horizontal_margin" 
android:paddingRight="@dimen/activity_horizontal_margin" 
android:paddingTop="@dimen/activity_vertical_margin" 
tools:context="de.lukas_schroederoutlook.connect.Overview_Screen$PlaceholderFragment"> 

<TextView 
    android:id="@+id/section_label" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" /> 

Answer 1

<fragment>タグ

<fragment 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:id="@+id/feed_fragment_portrait"/> 

<fragment 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:id="@+id/feed_fragment_landscape"/> 

は、それらの両方にclass="your.packagename.SomeFragment"を追加それがどのように見える

---

（あなたが実際には両方が必要な場合は通常、あなたがlandspaceや肖像画のための異なったレイアウトファイルを持っている...、両方のいずれかに持っていません）あなたはViewPagerを使用していますので、本当に<fragment>タグが必要ですか？私はあなたがそれらを取り除くことができると思います。クリケットが言ったように

<fragment 
    android:name="de.lukas_schroederoutlook.connect.FeedFragmentPortrait" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:id="@+id/feed_fragment_portrait"/> 

または

使用：

Answer 2

あなたはこのようなものが必要。