在Android中为选项卡式视图寻呼机单独返回导航

Question

在Android中为选项卡式视图寻呼机单独返回导航

San*_*Gil 8 java android android-fragments android-viewpager android-tablayout

我想要的是.

在选项卡滑动菜单上下文中,我想在选项卡内将片段替换为另一个片段,并维护选项卡菜单以及当前选项卡.当滑动到另一个选项卡并返回原始时,我希望显示最后一个片段.

例如,我有tab_a带Fragment_1,tab_b带Fragment_4和tab_c带Fragment_7.现在,我想在一个按钮,Fragment_1打开了我Fragment_2,但我希望能够左右滑动来的碎片tab_b和tab_c.当我返回tab_a时,Fragment_2必须显示.

MainActivity
    |
    |
ContainerFragment
    |
    |
    |_ _ _ Tab A
    |        |_ _ _ Fragment 1
    |        |
    |        |_ _ _ Fragment 2
    |        |
    |        |_ _ _ Fragment 3
    |        |
    |        |_ _ _ ...
    |        
    |_ _ _ Tab B
    |        |_ _ _ Fragment 4
    |        |
    |        |_ _ _ Fragment 5
    |        |
    |        |_ _ _ Fragment 6
    |        |
    |        |_ _ _ ...
    |
    |_ _ _ Tab C
    |        |_ _ _ Fragment 7
    |        |
    |        |_ _ _ Fragment 8
    |        |
    |        |_ _ _ Fragment 8
    |        |
    |        |_ _ _ ...

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我目前的主要活动.

XML

<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:tabMode="fixed"
            app:tabGravity="fill"/>
    </android.support.design.widget.AppBarLayout>

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

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

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码

public class MainActivity extends AppCompatActivity {

    private TabLayout tabLayout;

    private final static int[] tabIcons = {
            R.drawable.ic_tab_a,
            R.drawable.ic_tab_b,
            R.drawable.ic_tab_c
    };

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

        ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
        setupViewPager(viewPager);

        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);
        setupTabIcons();
    }

    private void setupTabIcons() {
        tabLayout.getTabAt(0).setIcon(tabIcons[0]);
        tabLayout.getTabAt(1).setIcon(tabIcons[1]);
        tabLayout.getTabAt(2).setIcon(tabIcons[2]);
    }

    private void setupViewPager(ViewPager viewPager) {
        ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
        adapter.addFrag(new Fragment1());
        adapter.addFrag(new Fragment4());
        adapter.addFrag(new Fragment7());
        viewPager.setAdapter(adapter);
    }

    class ViewPagerAdapter extends FragmentPagerAdapter {

        private final List<Fragment> mFragmentList = new ArrayList<>();

        ViewPagerAdapter(FragmentManager manager) {
            super(manager);
        }

        @Override
        public Fragment getItem(int position) {
            return mFragmentList.get(position);
        }

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

        void addFrag(Fragment fragment) {
            mFragmentList.add(fragment);
        }
    }
}

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片段

XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:background="@android:color/holo_blue_light"
    android:id="@+id/fragment_1"
    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="myContext">

    <Button
        android:text="Go to next Fragment"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:id="@+id/button_nextFrag" />

    <FrameLayout
        android:id="@+id/tab1_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</RelativeLayout>

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码

public class Fragment1 extends Fragment {

    private void goNextFragment() {
        FragmentTransaction trans = getFragmentManager().beginTransaction();
        trans.replace(R.id.tab1_container, new Fragment2());
        trans.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
        trans.addToBackStack(null);
        trans.commit();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment.
        View root = inflater.inflate(R.layout.fragment_1, container, false);
        // Go to next Fragment Button.
        final Button nextFrag = (Button) root.findViewById(R.id.button_nextFrag);
        nextFrag .setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                goNextFragment();
            }
        });
        return root;
    }
}

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编辑:

我有一些解决方案,但没有一个是完美的.如果我在MainActivity中放置一个Framelayaout,Fragment_1则正确替换为Fragment_2,但它也在tab_b和tab_c.如果FrameLayout在Fragment_1,我可以正确刷卡其他标签,但更换不好,原因Fragment_2打开,但Fragment_1也在那里.

Answer 1

mar*_*ani 2

您可以将 aViewPager与 a 一起使用TabLayout。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<android.support.v4.view.ViewPager
    android:id="@+id/viewpager"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1"/>
<android.support.design.widget.TabLayout
    android:id="@+id/tablayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"/>
</LinearLayout>

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然后创建一个类，该类扩展为使用您的首字母sFragmentStatePagerAdapter进行初始化：ViewPagerFragment

public class CustomPagerAdapter extends FragmentStatePagerAdapter {
    private final List<String> tabTitles = new ArrayList<String>() {{
        add("Fragment 1");
        add("Fragment 4");
        add("Fragment 7");
    }};

    private List<Fragment> tabs = new ArrayList<>();

    public CustomPagerAdapter(FragmentManager fragmentManager) {
        super(fragmentManager);

        initializeTabs();
    }

    private void initializeTabs() {
        tabs.add(HostFragment.newInstance(new Fragment1()));
        tabs.add(HostFragment.newInstance(new Fragment4()));
        tabs.add(HostFragment.newInstance(new Fragment7()));
    }

    @Override
    public Fragment getItem(int position) {
        return tabs.get(position);
    }

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

    @Override
    public CharSequence getPageTitle(int position) {
        return tabTitles.get(position);
    }
}

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包含实际内容的片段应该由包裹起来，如果您想导航，则HostFragment使用其子片段将当前片段替换为新片段，或者从片段堆栈中弹出最后一个片段。FragmentManager调用它replaceFragment来导航：

public class HostFragment extends BackStackFragment {
    private Fragment fragment;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        View view = inflater.inflate(R.layout.host_fragment, container, false);
        if (fragment != null) {
            replaceFragment(fragment, false);
        }
        return view;
    }

    public void replaceFragment(Fragment fragment, boolean addToBackstack) {
        if (addToBackstack) {
            getChildFragmentManager().beginTransaction().replace(R.id.hosted_fragment, fragment).addToBackStack(null).commit();
        } else {
            getChildFragmentManager().beginTransaction().replace(R.id.hosted_fragment, fragment).commit();
        }
    }

    public static HostFragment newInstance(Fragment fragment) {
        HostFragment hostFragment = new HostFragment();
        hostFragment.fragment = fragment;
        return hostFragment;
    }
}

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HostFragment 应该扩展抽象类BackstackFragment

public abstract class BackStackFragment extends Fragment {
    public static boolean handleBackPressed(FragmentManager fm)
    {
        if(fm.getFragments() != null){
            for(Fragment frag : fm.getFragments()){
                if(frag != null && frag.isVisible() && frag instanceof BackStackFragment){
                    if(((BackStackFragment)frag).onBackPressed()){
                        return true;
                    }
                }
            }
        }
        return false;
    }

    protected boolean onBackPressed()
    {
        FragmentManager fm = getChildFragmentManager();
        if(handleBackPressed(fm)){
            return true;
        } else if(getUserVisibleHint() && fm.getBackStackEntryCount() > 0){
            fm.popBackStack();
            return true;
        }
        return false;
    }
}

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将所有内容连接到MainActivity：

public class MainActivity extends AppCompatActivity {
    private CustomPagerAdapter customPagerAdapter;
    private ViewPager viewPager;
    private TabLayout tabLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        viewPager = (ViewPager) findViewById(R.id.viewpager);
        tabLayout = (TabLayout) findViewById(R.id.tablayout);
        customPagerAdapter = new CustomPagerAdapter(getSupportFragmentManager());

        // 2 is enough for us; increase if you have more tabs!
        viewPager.setOffscreenPageLimit(2);
        viewPager.setAdapter(customPagerAdapter);
        tabLayout.setupWithViewPager(viewPager);
    }

    @Override
    public void onBackPressed()
    {
        if(!BackStackFragment.handleBackPressed(getSupportFragmentManager())){
            super.onBackPressed();
        }
    }

    public void openNextFragment() {
        HostFragment hostFragment = (HostFragment) customPagerAdapter.getItem(viewPager.getCurrentItem());

        // your logic to change the fragments...
    }
}

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这个解决方案当然并不完美，但可以完成工作。在我关于这个问题的博客文章中阅读更多相关内容。

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