java - 屏幕旋转时 fragment 崩溃

Question

使用 FAB 按钮，应用程序在两个 fragment 之间交替。我试图在旋转屏幕时使当前 fragment 持续存在，但每次屏幕旋转时应用程序都会崩溃。我尝试了很多解决方案，但没有一个有效。为什么会崩溃？我正在使用 NetBeans，所以我不确定该由谁发布 logcat。

       public class agendaFalante extends AppCompatActivity
{
    /** Called when the activity is first created. */
    private Toolbar toolbar;
    private FloatingActionButton fab ;
    private listViewFrag lvfrag;
    private newEventFrag nef;
    private FragmentManager fragmentManager;
    private FragmentTransaction fragmentTransaction;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        toolbar = (Toolbar) findViewById (R.id.toolbar);
        setSupportActionBar(toolbar);
        fragmentManager = getSupportFragmentManager();
        fragmentTransaction = fragmentManager.beginTransaction();
        if (savedInstanceState == null) {
            lvfrag = new listViewFrag();
            fragmentTransaction.replace(R.id.ll, lvfrag, "lvfrag");
            fragmentTransaction.commit();
        }else{
            if(lvfrag!=null && lvfrag.isVisible()){
                fragmentTransaction.replace(R.id.ll, lvfrag);
                fragmentTransaction.commit();
            }else if(nef!=null && nef.isVisible()){
                fragmentTransaction.replace(R.id.ll, nef);
                fragmentTransaction.commit();
            }
        }
        fab = (FloatingActionButton)  findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            fragmentTransaction = fragmentManager.beginTransaction();
            if(nef!=null && nef.isVisible()){
                lvfrag = (listViewFrag) getSupportFragmentManager().findFragmentByTag("lvfrag");
                fragmentTransaction.replace(R.id.ll,lvfrag);
            }else{
                if(lvfrag.isVisible()){
                    nef = (newEventFrag) getSupportFragmentManager().findFragmentByTag("nef");
                    if(nef==null){
                        nef = new newEventFrag();
                        fragmentTransaction.replace(R.id.ll,nef,"nef");
                    }else{
                        fragmentTransaction.replace(R.id.ll,nef);
                    }                    
                }
            }
            fragmentTransaction.addToBackStack(null);
            fragmentTransaction.commit();
        }
    });
    }
    public boolean OnCreateOptionsMenu(Menu menu){
        getMenuInflater().inflate(R.menu.menu_layout,menu);
        return true;
    }

}

主xml

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/root"
    tools:context=".agendaFalante">
<LinearLayout android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:id="@+id/ll"
              android:orientation="vertical">
    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:background="?attr/colorPrimary"
        android:elevation="6dp"
        android:minHeight="?attr/actionBarSize"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    />

</LinearLayout>
<android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:clickable="true"
        android:src="@drawable/ic_done"
         app:layout_anchor="@id/ll"
          app:backgroundTint="#CE93D8"
        app:layout_anchorGravity="bottom|right|end"/>

</android.support.design.widget.CoordinatorLayout>

fragment 1 xml

public class listViewFrag extends Fragment{

    private ListView atividadesView;
    private ArrayList<String> alist;
    private ArrayAdapter<String> aDapter;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.listviewfrag, container, false);
        atividadesView = (ListView) view.findViewById(R.id.listView);
        alist = new ArrayList<String>();
        alist.add("oi");
        aDapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1,alist);
        atividadesView.setAdapter(aDapter);
        return view;
    }
    public void addText(String text){
        alist.add(text);
        aDapter.notifyDataSetChanged();
    }
}

XML fragment :

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
>

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

</LinearLayout>

fragment 2:

public class newEventFrag extends Fragment{

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.neweventfrag, container, false);
        return view;
    }

}

XML fragment

<TableLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport="true"
    >
    <TableRow
        android:layout_height="0dp"
        android:layout_weight="1">
        <EditText
                android:text="Insira o título"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="0.8"
            >
        </EditText>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="0.2"
            android:id="@+id/record"
            android:src="@drawable/ic_mic"
        >
        </Button>
    </TableRow>
    <TableRow
        android:layout_height="0dp"
        android:layout_weight="1">
        <DatePicker
            android:id="@+id/dpResult"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:datePickerMode="spinner"
            android:calendarViewShown="false"
        />
    </TableRow>
</TableLayout>

Answer 1

在您添加 fragment 的 Activity 的 AndroidManifest.xml 上写入此行::android:configChanges="orientation|screenSize|keyboardHidden"。

<activity
    android:name=".MainActivity"
    android:label="@string/title_activity_main"
    android:configChanges="orientation|screenSize|keyboardHidden">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>
</activity>