Android --- TabHost 切换时，改变选项卡下字体的状态（大小、加粗、默认被选中第一个）

上效果图：

MiddleFragment.java 代码如下

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TabHost;
import android.widget.TabWidget;
import android.widget.TextView;、
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import com.gxuwz.yixin.R;
import java.util.List;
import java.util.Map;


// 初中 Fragment
public class MiddleFragment extends Fragment {

    private View view;
    TabHost tabHost;
    String subjectArray[]; // 科目
    private List dataList;

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

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


        initView();
        tabHost.setup();
        //动态载入xml
        inflater.inflate(R.layout.fragment_first_grade, tabHost.getTabContentView());
        inflater.inflate(R.layout.fragment_two_grade, tabHost.getTabContentView());

        initData();
        initEvent();
        initAdapter();
        return view;
    }
    public void initView() {
        subjectArray = getContext().getResources().getStringArray(R.array.subjects);
        tabHost = view.findViewById(android.R.id.tabhost);
    }
    public void initData() {

        tabHost.addTab(tabHost.newTabSpec("tab1").setIndicator(subjectArray[0]).setContent(R.id.tab01));
        tabHost.addTab(tabHost.newTabSpec("tab2").setIndicator(subjectArray[1]).setContent(R.id.tab02));

        //设置 TabWidget 的布局参数
        final TabWidget tabWidget = tabHost.getTabWidget();

        // tabHost 选项卡改变的时候
        tabHost.setOnTabChangedListener(new TabHost.OnTabChangeListener() {
            @Override
            public void onTabChanged(String tabId) {
                for(int i = 0; i