FragmentTabHost Sample

activity_main.xml

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

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_above="@android:id/tabs"
            android:orientation="vertical">

            <FrameLayout
                android:id="@android:id/tabcontent"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:visibility="gone"/>

            <FrameLayout
                android:id="@+id/content"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />

        </LinearLayout>

        <TabWidget
            android:id="@android:id/tabs"
            android:layout_alignParentBottom="true"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:background="#dddddd"
            android:orientation="horizontal" />

    </RelativeLayout>

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

MainActivity.java

public class MainActivity extends AppCompatActivity {

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

        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTabHost host = findViewById(android.R.id.tabhost);
        host.setup(this, fragmentManager, R.id.content);

        TabHost.TabSpec tabSpec1 = host.newTabSpec("tab1");
        Button button1 = new Button(this);
        button1.setText("甲");
        button1.setBackgroundColor(0x00000000);
        tabSpec1.setIndicator(button1);
        Bundle bundle1 = new Bundle();
        bundle1.putString("name", "甲");
        host.addTab(tabSpec1, SampleFragment.class, bundle1);

        TabHost.TabSpec tabSpec2 = host.newTabSpec("tab2");
        Button button2 = new Button(this);
        button2.setText("乙");
        button2.setBackgroundColor(0x00000000);
        tabSpec2.setIndicator(button2);
        Bundle bundle2 = new Bundle();
        bundle2.putString("name", "乙");
        host.addTab(tabSpec2, SampleFragment.class, bundle2);
    }
}

sample_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:tools="http://schemas.android.com/tools">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="20dp"
        android:layout_above="@id/text_view">

        <Button
            android:id="@+id/show_button"
            android:layout_width="160dp"
            android:layout_height="50dp"
            android:layout_margin="8dp"
            android:text="Show" />

        <Button
            android:id="@+id/hide_button"
            android:layout_width="160dp"
            android:layout_height="50dp"
            android:layout_margin="8dp"
            android:text="Hide" />

    </LinearLayout>

    <TextView
        android:id="@+id/text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="36dp"
        android:textColor="#000000"
        tools:text="甲"
        android:layout_centerInParent="true"/>

</RelativeLayout>

SampleFragment.java

public class SampleFragment extends Fragment implements OnClickListener {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

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

        View view = inflater.inflate(R.layout.sample_fragment, null);

        TextView textView = view.findViewById(R.id.text_view);
        String name = getArguments().getString("name");
        textView.setText(name);

        Button hideButton = view.findViewById(R.id.hide_button);
        Button showButton = view.findViewById(R.id.show_button);

        hideButton.setOnClickListener(this);
        showButton.setOnClickListener(this);

        return view;
    }

    public void onClick(View view) {

        switch (view.getId()) {
            case R.id.hide_button:
                hideActionBar();
                break;
            case R.id.show_button:
                showActionBar();
                break;
            default:
                break;
        }
    }

    private void showActionBar() {
        ActionBar actionBar = getActionBar();
        if (actionBar != null) {
            actionBar.show();
        }
    }

    private void hideActionBar() {
        ActionBar actionBar = getActionBar();
        if (actionBar != null) {
            actionBar.hide();
        }
    }

    private ActionBar getActionBar() {
        return ((AppCompatActivity)getActivity()).getSupportActionBar();
    }
}