Android studio：如何使用 ViewPager 添加标签

Question

我想在片段中添加一个带有 pagerview（可滚动）的标签。

    public class MyFragment extends Fragment {
    private FragmentTabHost tabHost;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        tabHost = new FragmentTabHost(getActivity());
        tabHost.setup(getActivity(), getChildFragmentManager(), R.id.realtabcontent);
        tabHost.addTab(tabHost.newTabSpec("one").setIndicator("One"), OneFragment.class, null);
        tabHost.addTab(tabHost.newTabSpec("two").setIndicator("Two"), TwoFragment.class, null);
        return tabHost;
    }


    @Override
    public void onDestroyView(){
        super.onDestroyView();
        tabHost=null;
    }
}

采用这种布局

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.app.FragmentTabHost
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/tabhost"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

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

    </LinearLayout>
</android.support.v4.app.FragmentTabHost>

我尝试了几种解决方案，但都不起作用。 我需要使用片段，而不是片段活动。 编写的代码工作。

Answer 1

Tablayout + ViewPager的小代码

// find views by id
ViewPager vp= findViewById(R.id.viewpager);
TabLayout tl = findViewById(R.id.tablayout);

// attach tablayout with viewpager
tl.setupWithViewPager(vp);

ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());

// add your fragments
adapter.addFrag(new SampleFragment(), "Tab1");
adapter.addFrag(new SampleFragment(), "Tab2");
adapter.addFrag(new SampleFragment(), "Tab3");

// set adapter on viewpager
vp.setAdapter(adapter);

XML 布局

<?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">

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tablayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <androidx.viewpager.widget.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

</LinearLayout>

注意如果您还没有使用AndroidX，您需要在布局中更改以下内容。

• 将com.google.android.material.tabs.TabLayout 更改为android.support.design.widget.TabLayout
• Chagne androidx.viewpager.widget.ViewPager 到 android.support.v4.view.ViewPager

但我强烈建议您迁移到 AndroidX，请参阅 @this answer 了解原因。

这是 common ViewPagerAdapter 适用于所有您在应用中的 Viewpager。

public class ViewPagerAdapter extends FragmentStatePagerAdapter {
    private final List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();

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

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

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

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

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

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

如果需要在Fragment中设置ViewPager，请查看@this answer.

Answer 2

使用的xml文件是这样的：

<?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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <android.support.design.widget.TabLayout
        android:id="@+id/tabLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="?attr/colorPrimary"
        app:tabGravity="fill"
        app:tabMode="fixed"
        app:tabMaxWidth="0dp"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>

    <!-- View pager to swipe views -->
    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="match_parent"
        android:layout_height="fill_parent"/>

</LinearLayout>

你的 java 文件在这里：

public class MyFragment extends Fragment {

    private View view;
    private TabLayout tabLayout;

    //This is our viewPager
    private ViewPager viewPager;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        view = inflater.inflate(R.layout.sticker_fragment, container, false);

        tabLayout = (TabLayout) view.findViewById(R.id.tabLayout);

        viewPager = (ViewPager) view.findViewById(R.id.pager);

        Viewpager adapter = new Viewpager(getActivity().getSupportFragmentManager(), getActivity());

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


        tabLayout.setupWithViewPager(viewPager);
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @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) {

            }

            });

        return view;
    }



}

在那个viewpager适配器之后是这样的：

public class Viewpager extends FragmentStatePagerAdapter {

    final int PAGE_COUNT = 2;
    private String tabTitles[] = new String[]{"Local","Online"};
    private Context context;

    public Viewpager(FragmentManager fm, Context context) {
        super(fm);
        this.context = context;
    }

    @Override
    public Fragment getItem(int position) {
        switch (position){
            case 0:
                OneFragment oneFragment=new OneFragment();
                return oneFragment;
            case 1:
                TwoFragment twoFragment=new TwoFragment();
                return twoFragment;
            default:
                return null;
        }
    }

    @Override
    public int getCount() {
        return tabTitles.length;
    }

    @Override
    public CharSequence getPageTitle(int position) {

        return tabTitles[position];
    }

}