Question

我在很多地方搜索并尝试过以下问题的许多解决方案，希望你能帮忙！

我制作了带有6个片段的标签式活动，以及来自空白活动的日志记录屏幕。 Tabbed活动是一个主要活动，它有一个ViewPager容器来显示实际的选项卡，但是日志记录活动是第一个加载和显示的活动。在整个过程的某个地方（实际上很远），我注意到容器内的碎片偶尔会显示出来。当我旋转屏幕时，或者当我使用菜单中的Logout功能然后重新登录时，它们有时会重新出现（有时需要多次尝试才能显示备份）。我已经通读但无法弄明白。我试过改变

（getChildFragmentManager（），getResources（）））;

但我想我不会把它放在正确的位置。

我的MainActivty

public class MainActivity extends AppCompatActivity {
private boolean verified;
public static String token;

/**
 * The {@link android.support.v4.view.PagerAdapter} that will provide
 * fragments for each of the sections. We use a
 * {@link FragmentPagerAdapter} derivative, which will keep every
 * loaded fragment in memory. If this becomes too memory intensive, it
 * may be best to switch to a
 * {@link android.support.v4.app.FragmentStatePagerAdapter}.
 */
private SectionsPagerAdapter mSectionsPagerAdapter;


/**
 * The {@link ViewPager} that will host the section contents.
 */
private ViewPager mViewPager;

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


        // Get the Intent that started this activity and extract the string
    Bundle extras = getIntent().getExtras();
    if (extras != null) {
        verified = extras.getBoolean("verify");
        token = extras.getString("token");
        Toast.makeText(getBaseContext(), "Login Successful", 
Toast.LENGTH_SHORT).show();
    }
    if(verified != true) {
            logoutSuccessful();
    }


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

        // Create the adapter that will return a fragment for each of the 
three
        // primary sections of the activity.
        mSectionsPagerAdapter = new 
SectionsPagerAdapter(getSupportFragmentManager());
        //mSectionsPagerAdapter.saveState();

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(mViewPager);
        //getSupportActionBar().setIcon(R.drawable.logo_small);
        //set icons for tabs
        for (int i = 0; i < tabLayout.getTabCount(); i++) {
            if (i == 0) {
                tabLayout.getTabAt(i).setIcon(R.drawable.icon_scan);
            } else {
                if (i == 1) {

tabLayout.getTabAt(i).setIcon(R.drawable.icon_pricecheck);
                } else {
                    tabLayout.getTabAt(i).setIcon(R.drawable.logo_small);
                }
            }
        }



}

@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_main, 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;
    }
    if (id == R.id.action_logout) {
        logoutSuccessful();
        return true;
    }

    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
 //DELETED PLACEHOLDER CLASS

/**
 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
 * one of the sections/tabs/pages.
 */
public class SectionsPagerAdapter extends FragmentStatePagerAdapter {

    @Override
    public int getItemPosition(Object object) {
        return POSITION_NONE;
    }

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

    @Override
    public Fragment getItem(int position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a PlaceholderFragment (defined as a static inner class 
below).
      //  return PlaceholderFragment.newInstance(position + 1);
        switch (position){
            case 0: Tab1 tab1 = new Tab1();
                return tab1;
            case 1: Tab2 tab2 = new Tab2();
                return tab2;
            case 2: Tab3 tab3 = new Tab3();
                return tab3;
            case 3: Tab4 tab4 = new Tab4();
                return tab4;
            case 4: Tab5 tab5 = new Tab5();
                return tab5;
            case 5: Tab6 tab6 = new Tab6();
                return tab6;
        }
        return null;
    }

    @Override
    public int getCount() {
        // Show total pages.
        return 6;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "SCAN";
            case 1:
                return "PRICE CHECK";
            case 2:
                return "SECTION 3";
            case 3:
                return "SECTION 4";
            case 4:
                return "SECTION 5";
            case 5:
                return "SECTION 6";
        }
        return null;
    }
}
private void logoutSuccessful(){
    Intent myIntent = new Intent(MainActivity.this, Login.class);
    MainActivity.this.startActivity(myIntent);
    overridePendingTransition(R.anim.slide_in, R.anim.slide_out);
    finish();
}
}

TAB1：

public class Tab1 extends android.support.v4.app.Fragment {
Button btnUpc;
EditText txtUPC;
Vector<UPCProductObject> v = new Vector<>();
Editable value;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup 
container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.tab1, container,false);
    lblUpcResult = (TextView) v.findViewById(R.id.lblUPCResult);
    txtUPC = (EditText) v.findViewById(R.id.txtUPC);
    btnUpc = (Button) v.findViewById(R.id.btnUPC);
    btnUpc.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v) {
            //hide keyboard
            InputMethodManager mgr = (InputMethodManager) 
getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
            mgr.hideSoftInputFromWindow(txtUPC.getWindowToken(), 0);
            btnUpc.setEnabled(false);
            value = txtUPC.getText();
          new searchUPC().execute();
        }});
    return v;
}

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    if (savedInstanceState != null) {
        getChildFragmentManager().beginTransaction()
                .add(R.id.container, new Tab1(), "Scan")
                .commit();
    }
}

activity_main 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.dabush.shen.mcrpos.MainActivity">

<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="enterAlways"
        app:popupTheme="@style/AppTheme.PopupOverlay">

        <FrameLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">
            <ImageView
                android:layout_width="90dp"
                android:layout_height="50dp"
                android:src="@drawable/logo_small"
                android:layout_gravity="left"
                />
        </FrameLayout>
    </android.support.v7.widget.Toolbar>

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

<android.support.v4.view.ViewPager
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginBottom="75dp"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" />

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom"
    android:minHeight="80dp">

    <android.support.design.widget.TabLayout
        android:id="@+id/tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabMode="scrollable"
        app:tabSelectedTextColor="@color/textColorPrimary"
        app:tabTextColor="#FFD5D2D2" />
</android.support.design.widget.AppBarLayout>

<!--FLOATING EDITABLE BUTTON
 <android.support.design.widget.FloatingActionButton
     android:id="@+id/fab"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_gravity="end|bottom"
     android:layout_margin="@dimen/fab_margin"
     app:srcCompat="@android:drawable/ic_dialog_email" />
     -->

tab1 xml

<TextView
    android:id="@+id/section_label"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_marginTop="13dp"
    android:layout_toLeftOf="@+id/tblSearch"
    android:layout_toStartOf="@+id/tblSearch" />

<TextView
    android:id="@+id/textView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/tab1_title"
    android:textSize="24sp"
    android:layout_alignTop="@+id/section_label"
    android:layout_centerHorizontal="true" />

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="12dp"
    android:text="@string/scan_desc"
    android:layout_below="@+id/textView"
    android:layout_centerHorizontal="true" />

<TableLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="14dp"
    android:id="@+id/tblSearch"
    android:layout_below="@+id/textView2"
    android:layout_centerHorizontal="true">

    <TableRow
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <EditText
            android:id="@+id/txtUPC"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ems="10"
            android:inputType="number"
            android:textAlignment="center" />
    </TableRow>

    <TableRow
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="0dp">

        <Button
            android:id="@+id/btnUPC"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="SEARCH" />

    </TableRow>

</TableLayout>

<TableLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true">

    <TableRow
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <TableRow
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</TableLayout>

<TextView
    android:id="@+id/lblUPCResult"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/tblSearch"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="91dp"
    android:textAlignment="center"
    android:textSize="12sp" />

<ListView
    android:id="@+id/listUpc"
    android:layout_width="match_parent"
    android:layout_height="375dp"
    android:layout_below="@+id/tblSearch"
    android:layout_marginLeft="0dp"
    android:layout_marginRight="0dp"
    android:textAlignment="center" />

Answer 1

你不需要在第一个片段中使用getChildFragmentManager（）。beginTransaction（）。在活动生命周期中，onRotate，活动被销毁并重新创建，您需要将其保存在saveInstance上并重新加载UI onRestoreInstance

ViewPager Fragment偶尔不会膨胀/加载

1 个答案: