简单效果：

效果

fragment_radio.xml主要代码

<?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"
   >

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/radio_fragment_content"
        android:layout_above="@+id/radio">
    </FrameLayout>

    <LinearLayout
        android:id="@+id/radio"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_alignParentBottom="true">
        <RadioGroup
            android:id="@+id/radio_group"
            android:layout_width="match_parent"
            android:layout_height="56dp"
            android:layout_alignParentBottom="true"
            android:background="#ffffff"
            android:orientation="horizontal">
            <RadioButton
                android:id="@+id/rb_home"
                style="@style/radiobutton_style"
                android:checked="true"
                android:drawableTop="@drawable/ic_home"
                android:text="主页" />
            <RadioButton
                android:id="@+id/rb_like"
                style="@style/radiobutton_style"
                android:drawableTop="@drawable/ic_like"
                android:text="喜欢"/>
            <RadioButton
                android:id="@+id/rb_me"
                style="@style/radiobutton_style"
                android:drawableTop="@drawable/ic_person"
                android:text="我"/>
        </RadioGroup>
    </LinearLayout>

</RelativeLayout>

页面为RadioFragment

public class RadioFragment extends Fragment implements RadioGroup.OnCheckedChangeListener {
    @BindView(R.id.rb_home)
    RadioButton rbHome;
    @BindView(R.id.rb_like)
    RadioButton rbLike;
    @BindView(R.id.rb_me)
    RadioButton rbMe;
    @BindView(R.id.radio_group)
    RadioGroup radioGroup;
    Unbinder unbinder;
    private HomeFragment homeFragment;
    private LikeFragment likeFragment;
    private  MeFragment meFragment;
    public RadioFragment() {
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_radio, container, false);
        unbinder = ButterKnife.bind(this, view);
        radioGroup.setOnCheckedChangeListener(this);//对radiogroup进行监听
        return view;
    }

    @Override
    public void onStart() {
        setDefaultFragment();//写在onCreateView里面，当页面跑到其他Fragment再回来就不会生效
        super.onStart();
    }

    private void setDefaultFragment() {
 //默认为homeFragment
        if (rbHome.isChecked()) {
            FragmentTransaction transaction = getFragmentManager().beginTransaction();
            homeFragment = new HomeFragment();
            transaction.replace(R.id.radio_fragment_content, homeFragment).commit();
        }
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        unbinder.unbind();
    }
//主要代码
    @Override
    public void onCheckedChanged(RadioGroup radioGroup, @IdRes int i) {
        FragmentTransaction transaction=getFragmentManager().beginTransaction();
        switch (i){
            case R.id.rb_home:
                if (homeFragment==null){
                    homeFragment= new HomeFragment();
                }
                transaction.replace(R.id.radio_fragment_content,homeFragment).commit();
                break;
            case R.id.rb_like:
                if (likeFragment==null){
                    likeFragment=new LikeFragment();
                }
                transaction.replace(R.id.radio_fragment_content,likeFragment).commit();
                break;
            case R.id.rb_me:
                if (meFragment==null){
                    meFragment=new MeFragment();
                }
                transaction.replace(R.id.radio_fragment_content,meFragment).commit();
                break;
        }

    }
}

radiobutton的style文件

style文件
    <style name="radiobutton_style">
        <item name="android:layout_width">0dp</item>
        <item name="android:padding">3dp</item>
        <item name="android:layout_height">match_parent</item>
        <item name="android:layout_weight">1</item>
        <item name="android:button">@null</item>
        <item name="android:gravity">center</item>
        <item name="android:textSize">12sp</item>
    </style>

每个按钮的drawable是一个selector，如图：

image.png

然后对于相应的三个fragment，也是是分简单，给出一个示例，具体剩下的就自己去添加了：

public class HomeFragment  extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view= inflater.inflate(R.layout.sub_fragment_home,container,false);
        return view;
    }
}