Android 如何将带有ViewPager的Tablayout放在属于导航抽屉的片段中

我正在尝试开发一个应用程序，它有一个导航抽屉，在抽屉的一个片段中，我想放一个

Tablayout

，其中包含

ViewPager

。一切似乎都很好，但有个问题。这是我的导航抽屉：

当我第一次启动应用程序时，它会向我显示home片段，其中有3个标签，如下所示

每个选项卡中只有一个文本。第一个选项卡有“搜索”，第二个选项卡有“购物车”，第三个选项卡有“历史记录”。当我切换到导航的另一个片段并切换回主页时，我意识到第一个选项卡中的“搜索”一词并没有出现

我刷到第二个标签，同样的事情发生了，但第三个标签上仍然显示“历史”一词。我向后滑动到第一个选项卡，显示“搜索”一词，但第二个选项卡中的词不会再显示，不管我来回滑动多少次

所以我决定将

Log.d（）

放在方法

onCreate

和

onCreateView

的内部，以查看每个选项卡片段发生了什么。当应用程序第一次打开时，它显示home fragment，其中有3个选项卡，如我前面所说，但只调用了第一个和第二个选项卡的

onCreate

和

onCreateView

。当我滑动到第二个选项卡时，会调用第三个选项卡的

onCreate

和

onCreateView

。我刷到第三个选项卡，什么也没发生，但当我从第三个选项卡刷回第二个选项卡时，会调用第一个选项卡的

onCreateView

之后，我切换到导航抽屉的另一个片段，然后切换回主页。没有调用任何选项卡的

onCreate

和

onCreateView

方法，因此不会显示任何内容。我刷到第二个标签，还是没什么。但当我滑动到第三个选项卡时，会调用方法

onCreate

和

onCreateView

，并显示单词“history”。我扫回第二个选项卡，调用第一个选项卡的创建视图而不是第二个选项卡，因此第二个选项卡上没有任何内容，然后我扫回第一个选项卡，显示“搜索”一词，没有调用任何方法。之后，每次我从第一个选项卡滑动到第二个选项卡时，都会调用第三个选项卡的

onCreateView

，当我从第三个选项卡滑动到第二个选项卡时，都会调用第一个选项卡的

onCreateView

。我不知道是什么导致了这种行为，请帮帮我。代码如下：

导航抽屉活动：

package activity;
import android.os.Handler;
import android.support.design.widget.NavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.MenuItem;
import android.view.View;

import com.example.hoangvu.vbuy.R;

import fragment.HomeFragment;
import fragment.ProfileFragment;
import fragment.SettingFragment;
public class NavigationDrawerActivity extends AppCompatActivity {

private NavigationView navigationView;
private DrawerLayout drawer;
private View navHeader;
private Toolbar toolbar;


// index to identify current nav menu item
public static int navItemIndex = 0;

// tags used to attach the fragments
private static final String TAG_HOME = "home";
private static final String TAG_PROFILE = "profile";
private static final String TAG_SETTINGS = "settings";
public static String CURRENT_TAG = TAG_HOME;

// toolbar titles respected to selected nav menu item
private String[] activityTitles;
private Handler mHandler;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_navigation_drawer);
    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    mHandler = new Handler();

    drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    navigationView = (NavigationView) findViewById(R.id.nav_view);

    // Navigation view header
    navHeader = navigationView.getHeaderView(0);

    // load toolbar titles from string resources
    activityTitles = getResources().getStringArray(R.array.nav_item_activity_titles);

    // initializing navigation menu
    setUpNavigationView();

    if (savedInstanceState == null) {
        navItemIndex = 0;
        CURRENT_TAG = TAG_HOME;
        loadHomeFragment();
    }
    }

    /***
    * Returns respected fragment that user
    * selected from navigation menu
    */
    private void loadHomeFragment() {
    // selecting appropriate nav menu item
    selectNavMenu();

    // set toolbar title
    setToolbarTitle();

    // if user select the current navigation menu again, don't do anything
    // just close the navigation drawer
    if (getSupportFragmentManager().findFragmentByTag(CURRENT_TAG) != null) {
        drawer.closeDrawers();
        return;
    }

    // Sometimes, when fragment has huge data, screen seems hanging
    // when switching between navigation menus
    // So using runnable, the fragment is loaded with cross fade effect
    // This effect can be seen in GMail app
    Runnable mPendingRunnable = new Runnable() {
        @Override
        public void run() {
            // update the main content by replacing fragments
            Fragment fragment = getHomeFragment();
            FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
            fragmentTransaction.setCustomAnimations(android.R.anim.fade_in,
                    android.R.anim.fade_out);
            fragmentTransaction.replace(R.id.frame, fragment, CURRENT_TAG);
            fragmentTransaction.commitAllowingStateLoss();
        }
    };

    // If mPendingRunnable is not null, then add to the message queue
    if (mPendingRunnable != null) {
        mHandler.post(mPendingRunnable);
    }

    //Closing drawer on item click
    drawer.closeDrawers();

    // refresh toolbar menu
    invalidateOptionsMenu();
    }

    private Fragment getHomeFragment() {
        switch (navItemIndex) {
            case 0:
            // home
                HomeFragment homeFragment = new HomeFragment();
                return homeFragment;
            case 1:
            // Profile
                ProfileFragment profileFragment = new ProfileFragment();
                return profileFragment;
            case 2:
            // settings
                SettingFragment settingsFragment = new SettingFragment();
                return settingsFragment;
            default:
                return new HomeFragment();
        }
    }

    private void setToolbarTitle() {
        getSupportActionBar().setTitle(activityTitles[navItemIndex]);
    }

    private void selectNavMenu() {
        navigationView.getMenu().getItem(navItemIndex).setChecked(true);
    }

    private void setUpNavigationView() {
        //Setting Navigation View Item Selected Listener to handle the item click of the navigation menu
        navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {

        // This method will trigger on item Click of navigation menu
        @Override
        public boolean onNavigationItemSelected(MenuItem menuItem) {

            //Check to see which item was being clicked and perform appropriate action
            switch (menuItem.getItemId()) {
                //Replacing the main content with ContentFragment Which is our Inbox View;
                case R.id.nav_home:
                    navItemIndex = 0;
                    CURRENT_TAG = TAG_HOME;
                    break;
                case R.id.nav_profile:
                    navItemIndex = 1;
                    CURRENT_TAG = TAG_PROFILE;
                    break;
                case R.id.nav_settings:
                    navItemIndex = 2;
                    CURRENT_TAG = TAG_SETTINGS;
                    break;
                default:
                    navItemIndex = 0;
            }

            //Checking if the item is in checked state or not, if not make it in checked state
            if (menuItem.isChecked()) {
                menuItem.setChecked(false);
            } else {
                menuItem.setChecked(true);
            }
            menuItem.setChecked(true);

            loadHomeFragment();

            return true;
        }
        });


        ActionBarDrawerToggle actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.openDrawer, R.string.closeDrawer) {

        @Override
        public void onDrawerClosed(View drawerView) {
            // Code here will be triggered once the drawer closes as we dont want anything to happen so we leave this blank
            super.onDrawerClosed(drawerView);
        }

        @Override
        public void onDrawerOpened(View drawerView) {
            // Code here will be triggered once the drawer open as we dont want anything to happen so we leave this blank
            super.onDrawerOpened(drawerView);
        }
        };

        //Setting the actionbarToggle to drawer layout
        drawer.addDrawerListener(actionBarDrawerToggle);

        //calling sync state is necessary or else your hamburger icon wont show up
        actionBarDrawerToggle.syncState();
      }
      }

活动\u导航\u drawer.xml：

<?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"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/top_parent"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:orientation="vertical"
tools:context="activity.NavigationDrawerActivity">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        android:theme="@style/MyToolBarTheme"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

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

<android.support.v4.widget.DrawerLayout 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/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <FrameLayout
        android:id="@+id/frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">
    </FrameLayout>

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

 </android.support.v4.widget.DrawerLayout>
 </LinearLayout>

fragment_search.xml：

<FrameLayout 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"
tools:context="fragment.SearchFragment2">

<!-- TODO: Update blank fragment layout -->
<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:text="Search" />

</FrameLayout>

我也犯了这样的错误。

使用
getChildFragmentManager（）
而不是
getActivity（）。getSupportFragmentManager（）
发布整个代码不是一个好主意。发布与问题相关的代码段。查看寻呼机默认情况下存储当前代码段的左、右代码段。应用程序第一次打开时，会创建“搜索”和“购物车”。当您切换到“购物车”时，将创建“历史”片段。当您切换到“历史记录”时，“搜索”片段实例将被销毁。。因此，当您从“历史”切换回“购物车”时，“搜索”片段将再次创建。这将帮助您确定何时为每个片段调用onCreate，并有希望指出确切的问题。。您可以使用viewPager.setOffscreenPageLimit（3）@amarok谢谢，这解释了很多，但有一件事我仍然不知道为什么：当我使用导航抽屉切换到另一个片段并切换回主片段（包括3个选项卡片段）时，“搜索”片段不会显示，直到我滑动到“历史”片段并滑动回它。无论我刷了多少次，“cart”片段都不会再出现。我看不到代码中有任何问题，所以如果不运行代码，我就无法真正回答这个问题。您是否检查了在通过导航抽屉切换回主屏幕时是否调用了“搜索”片段功能
package fragment;

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.example.hoangvu.vbuy.R;


public class SearchFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";

// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;

private OnFragmentInteractionListener mListener;

public SearchFragment() {
    // Required empty public constructor
}

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 *
 * @param param1 Parameter 1.
 * @param param2 Parameter 2.
 * @return A new instance of fragment SearchFragment2.
 */
// TODO: Rename and change types and number of parameters
public static SearchFragment2 newInstance(String param1, String param2) {
    SearchFragment fragment = new SearchFragment();
    Bundle args = new Bundle();
    args.putString(ARG_PARAM1, param1);
    args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Log.d("SearchFragment","onCreate");
    if (getArguments() != null) {
        mParam1 = getArguments().getString(ARG_PARAM1);
        mParam2 = getArguments().getString(ARG_PARAM2);
    }
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    Log.d("SearchFragment","onCreateView");
    return inflater.inflate(R.layout.fragment_search, container, false);
}

// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
    if (mListener != null) {
        mListener.onFragmentInteraction(uri);
    }
}


@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}

}

<FrameLayout 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"
tools:context="fragment.SearchFragment2">

<!-- TODO: Update blank fragment layout -->
<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:text="Search" />

</FrameLayout>