android viewpager with tablayout - 如何在选项卡内添加其他片段？

so i have the classic viewpager in a tablayout that looks something like this:

我的 viewPagerAdapter 类如下所示：

公共类 HomePagerAdapter 扩展 FragmentPagerAdapter { int mNumOfTabs；

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

@Override
public Fragment getItem(int position) {

    switch (position) {
        case 0:
            TabHomeFragment tab1 = new TabHomeFragment();
            return tab1;
        case 1:
            TabShopFragment tab2 = new TabShopFragment();
            return tab2;
        case 2:
            TabMeFragment tab3 = new TabMeFragment();
            return tab3;
        default:
            return null;
    }
}

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

}

所以现在在其中一个选项卡上我需要在其顶部添加一个片段。所以它确实是一个搜索片段。我在选项卡栏中进行搜索，并且希望后端搜索结果仅出现在一个选项卡（第一个选项卡）中。但我希望搜索结果显示在名为 searchFragmentResults 的片段中，并且希望将其放置在第一个选项卡的顶部。然后，当用户点击后退按钮时，它将返回到第一个选项卡中的原始内容。这可以通过查看寻呼机实现吗？

so visually when i hit the search icon on the first tabs tabBar it should bring up a searchView and when i search for the users query it should bring up a another fragment with the results but only in the tab that it started from. Here is an example:

我不能打电话fragtransaction.replace(somecontentview, somefragment); (or its add method)因为我没有将它们添加到内容视图中。我让 viewpager 帮我做这件事。那么这是如何实现的呢？

我想出了如何做到这一点。该选项卡应该是一个片段，其目的是仅包含其他片段。这个想法是基于此SO https://stackoverflow.com/a/19859871/835883。但我需要为 viewPager 做这件事。让我们完成这些步骤。首先是viewpager适配器：

    public class HomePagerAdapter extends FragmentStatePagerAdapter {

    //integer to count number of tabs
    int tabCount;
    private Fragment mCurrentFragment;

    private String[] tabTitles = new String[]{"tab0", "tab1", "tab2", "tab3"};

    //Constructor to the class
    public HomePagerAdapter(FragmentManager fm, int tabCount) {
        super(fm);
        this.tabCount = tabCount;
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                TabHomeContainerFragment tab1 = new Tab0ContainerFragment();
                return tab1;
            case 1:
                TabShopFragment tab2 = new Tab1ContainerFragment(); 
                return tab2;
            case 2:
                TabMeFragment tab3 = new Tab2ContainerFragment();
                return tab3;
            case 3:
                TabBagFragment tab4 = new Tab3ContainerFragment();
                return tab4;
            default:
                return null;
        }
    }

    //Overriden method getCount to get the number of tabs
    @Override
    public int getCount() {
        return tabCount;
    }

    public Fragment getCurrentFragment() {
        return mCurrentFragment;
    }
    //* this is key to get the current tab to pop the fragments afterwards**/
    @Override
    public void setPrimaryItem(ViewGroup container, int position, Object object) {
        if (getCurrentFragment() != object) {
            mCurrentFragment = ((Fragment) object);
        }
        super.setPrimaryItem(container, position, object);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return tabTitles[position];
    }

让我们进入一个容器看看它的样子：

将其添加到所有容器的 xml 中（以及您在视觉上想要的任何其他内容，但它们都必须具有相同的 container_framelayout id：

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

    <FrameLayout android:id="@+id/container_framelayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        xmlns:android="http://schemas.android.com/apk/res/android" />

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

你不必将它放在 coordinatorLayout 中，我只是发现它修复了一些错误并且运行良好。

在你的片段基类中，我从上面提到的SO中复制了几乎相同的代码，但如果你想添加标签或不添加标签，请稍加修改：

public void replaceFragment(Fragment fragment, boolean addToBackStack,String tag) {
        FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
        if (addToBackStack) {
            transaction.addToBackStack(null);
        }
        transaction.replace(R.id.container_framelayout, fragment,tag);
        transaction.commit();
        getChildFragmentManager().executePendingTransactions();
    }

    public boolean popFragment() {
        Log.e("test", "pop fragment: " + getChildFragmentManager().getBackStackEntryCount());
        boolean isPop = false;
        if (getChildFragmentManager().getBackStackEntryCount() > 0) {
            isPop = true;
            getChildFragmentManager().popBackStack();
        }
        return isPop;
    }

现在让我们看看活动布局：

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


    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="@color/white"/>

    <android.support.design.widget.TabLayout
        android:id="@+id/tabLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabMode="fixed"
        app:tabGravity="fill"
        app:tabTextColor="@color/black"
        app:tabSelectedTextColor="@android:color/darker_gray"
        />

现在我将向您展示如何在托管选项卡布局的活动中设置选项卡布局： 其标准：

    public class HomePageActivity  implements TabLayout.OnTabSelectedListener {

               private final int NUM_OF_TABS = 4;

               @BindView(R.id.pager)
               public ViewPager viewPager;

               public HomePagerAdapter adapter;

               @BindView(R.id.tabLayout)
               TabLayout tabLayout;

               @NonNull
               @Override
               public HomePagePresenter createPresenter() {
                   return new HomePagePresenter();
               }

               @Override
               protected void onCreate(Bundle savedInstanceState) {
                   super.onCreate(savedInstanceState);
                   setContentView(R.layout.activity_homepage);
                   ButterKnife.bind(this);
                   initView();
               }

               private void initView() {

                   for (int i = 0; i < NUM_OF_TABS; i++)
                       tabLayout.addTab(tabLayout.newTab());

                   adapter = new HomePagerAdapter(getSupportFragmentManager(), tabLayout.getTabCount());

                   //Adding adapter to pager
                   viewPager.setAdapter(adapter);

                   tabLayout.addOnTabSelectedListener(this);

                   tabLayout.setupWithViewPager(viewPager);

                   // configure tab icons
                   int[] imageTabResId = {
                           R.drawable.welcome1,
                           R.drawable.welcome2,
                           R.drawable.welcome3,
                           R.drawable.welcome1};

                   for (int i = 0; i < imageTabResId.length; i++) {
                       tabLayout.getTabAt(i).setIcon(imageTabResId[i]);
                   }
               }

/** this is key. we get the current fragment showing and pop it **/
               @Override
               public void onBackPressed() {
                   boolean isPopFragment = false;
                   isPopFragment = ((BaseFragment) adapter.getCurrentFragment()).popFragment();
                   if (!isPopFragment) {
                       finish();
                   }
               }

               @Override
               public void onTabSelected(TabLayout.Tab tab) {
                   viewPager.setCurrentItem(tab.getPosition());
               }

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

               }

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

               }
           }

我想主要部分是 onBackPress 获取当前片段。