安卓里面Fragmen和ViewParger2结合使用代码

在Android中，可以使用Fragment和ViewPager2组合来创建可滑动的页面，以下是一个示例代码：

1. 创建两个Fragment：

FragmentOne.java

public class FragmentOne extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_one, container, false);
        TextView textView = view.findViewById(R.id.text_view);
        textView.setText("Fragment One");
        return view;
    }
}

FragmentTwo.java

public class FragmentTwo extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_two, container, false);
        TextView textView = view.findViewById(R.id.text_view);
        textView.setText("Fragment Two");
        return view;
    }
}

2. 在布局文件中添加ViewPager2：

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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/constraint_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/view_pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

3. 在MainActivity中设置ViewPager2：

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private ViewPager2 viewPager;

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

        viewPager = findViewById(R.id.view_pager);

        List<Fragment> fragmentList = new ArrayList<>();
        fragmentList.add(new FragmentOne());
        fragmentList.add(new FragmentTwo());

        FragmentAdapter adapter = new FragmentAdapter(getSupportFragmentManager(), getLifecycle(), fragmentList);

        viewPager.setAdapter(adapter);
    }
}

4. 创建FragmentAdapter：

public class FragmentAdapter extends FragmentStateAdapter {

    private List<Fragment> fragmentList;

    public FragmentAdapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle, List<Fragment> fragmentList) {
        super(fragmentManager, lifecycle);
        this.fragmentList = fragmentList;
    }

    @NonNull
    @Override
    public Fragment createFragment(int position) {
        return fragmentList.get(position);
    }

    @Override
    public int getItemCount() {
        return fragmentList.size();
    }
}

这样就可以在ViewPager2中使用两个Fragment了。