java - Android Tablayout，为什么标签不移动？

Question

我正在学习本教程 https://www.youtube.com/watch?v=zcnT-3F-9JA我从 github 上使用了他的代码，但输出是错误的。我在顶部放了 3 个选项卡，当我按下选项卡时， Activity 应该会改变，但实际上什么也没有发生，屏幕上仍然只有我的 main_activity。希望有人会帮忙。这是我的代码

PS - 是的，每个 fragment 我也有 3 个 xml 文件(即使我也有 main_activity，但我必须找出问题所在，然后将 1tab 分配给主要 Activity )。对于这 3 个选项卡，我还有 3 个 java 文件。

XML

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.NestedScrollView 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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFFFFF"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

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


        <TextView
            android:id="@+id/lvltext"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/expa"
            android:layout_centerInParent="true"
            android:fontFamily="@font/futuracondensed"
            android:text="@string/leveltext"
            android:textColor="@color/black"
            android:textSize="30sp" />

        <TextView

            android:id="@+id/lvlnum"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/lvltext"
            android:layout_centerInParent="true"
            android:fontFamily="@font/futuracondensed"
            android:text="@string/levelnum"
            android:textColor="@color/black"
            android:textSize="30sp" />

        <ImageView
            android:id="@+id/girl"
            android:layout_width="wrap_content"
            android:layout_height="262dp"
            android:layout_below="@id/lvlnum"
            android:src="@drawable/girl" />

        <Button
            android:id="@+id/button"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_below="@id/girl"
            android:fontFamily="@font/futuracondensed"
            android:text="@string/button"
            android:textColor="@color/black" />

        <ImageView
            android:id="@+id/girl2"
            android:layout_width="match_parent"
            android:layout_height="258dp"
            android:layout_below="@id/button"
            android:src="@drawable/fitnessmodel" />

        <Button
            android:id="@+id/button2"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_below="@id/girl2"
            android:fontFamily="@font/futuracondensed"
            android:text="@string/button2"
            android:textColor="@color/black" />

        <LinearLayout
            android:layout_below="@id/tabs"
            android:id="@+id/expa"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">

            <LinearLayout
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:orientation="vertical">

                <TextView
                    android:id="@+id/team_a_score"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:fontFamily="@font/futuracondensed"
                    android:gravity="center"
                    android:paddingBottom="5dp"
                    android:text="0"
                    android:textColor="@color/black"
                    android:textSize="60sp" />
            </LinearLayout>

            <View
                android:layout_width="1dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@color/black" />

            <LinearLayout
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:orientation="vertical">

                <TextView
                    android:id="@+id/team_b_score"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:fontFamily="@font/futuracondensed"
                    android:gravity="center"
                    android:paddingBottom="5dp"
                    android:text="100"
                    android:textColor="@color/black"
                    android:textSize="60sp" />
            </LinearLayout>
        </LinearLayout>
    </RelativeLayout>

</android.support.v4.widget.NestedScrollView>

Java

public class MainActivity extends AppCompatActivity {
    private SectionsPageAdapter mSectionsPageAdapter;

    private ViewPager mViewPager;

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

        mSectionsPageAdapter = new SectionsPageAdapter(getSupportFragmentManager());

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

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

    private void setupViewPager(ViewPager viewPager) {
        SectionsPageAdapter adapter = new SectionsPageAdapter(getSupportFragmentManager());
        adapter.addFragment(new Tab1Fragment(), "TAB1");
        adapter.addFragment(new Tab2Fragment(), "TAB2");
        adapter.addFragment(new Tab3Fragment(), "TAB3");
        viewPager.setAdapter(adapter);
    }


    @Override
    public void onResume() {
        super.onResume();
    }
}



public class SectionsPageAdapter extends FragmentPagerAdapter {

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

        public void addFragment(Fragment fragment, String title) {
            mFragmentList.add(fragment);
            mFragmentTitleList.add(title);
        }

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

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

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

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

Answer 1

使用你所遵循的库中给出的这个 XML，然后无论你想将它们添加到你已经采用的 fragment 布局中的任何设计。一切都会很好

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.chirag.slidingtabsusingviewpager.MainActivity">

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

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="SlidingTabsUsingViewPager"
            android:textSize="20dp"/>


    </android.support.v7.widget.Toolbar>

    <android.support.design.widget.TabLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tablayout"
        android:background="@color/colorPrimary"
        android:minHeight="?attr/actionBarSize"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

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

    <android.support.v4.view.ViewPager
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:id="@+id/pager">

    </android.support.v4.view.ViewPager>

</LinearLayout>