使用ViewPager从Activity更改片段TextView

<androidx.viewpager.widget.ViewPager
    android:id="@+id/viewPager"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

ViewPager viewPager = findViewById(R.id.viewPager);
FragmentPagerAdapter adapter = new FragmentPagerAdapter(getSupportFragmentManager()) {
    @NonNull
    @Override
    public Fragment getItem(int position) {
        // 根据位置返回对应的片段实例
        return MyFragment.newInstance(position);
    }

    @Override
    public int getCount() {
        // 返回片段的数量
        return 3;
    }
};
viewPager.setAdapter(adapter);

<TextView
    android:id="@+id/textView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

public class MyFragment extends Fragment {
    private TextView textView;

    public static MyFragment newInstance(int position) {
        MyFragment fragment = new MyFragment();
        Bundle args = new Bundle();
        args.putInt("position", position);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_my, container, false);
        textView = view.findViewById(R.id.textView);

        // 获取传递的位置参数
        int position = getArguments().getInt("position");

        // 根据位置设置不同的文本内容
        switch (position) {
            case 0:
                textView.setText("第一个片段");
                break;
            case 1:
                textView.setText("第二个片段");
                break;
            case 2:
                textView.setText("第三个片段");
                break;
        }

        return view;
    }
}