安卓工作室 : how add tabs with ViewPager

Question

我想在 fragment 中添加一个带有 pagerview(可滚动)的选项卡。

    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 fragment ，而不是 fragment Activity 。编写的代码有效。

Answer 1

Tablayout + ViewPager 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 如果您没有使用 AndroidX但是，您需要更改以下布局。

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

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

这是通用 ViewPagerAdapter 对于所有您在应用程序中的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.