fragment加radio不可滑动

public class MainActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener {
    private ArrayList<Fragment> arrayList;
    private RadioGroup rg;
    private RadioButton[] radioButtons;
    private FragmentManager manager;
    private int count=0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        arrayList = new ArrayList<>();
        NewsFragment fragment1 = new NewsFragment();
        AppraisalFragment fragment2 = new AppraisalFragment();
        PictureFragment fragment3 = new PictureFragment();
        CommentFragment fragment4 = new CommentFragment();
        arrayList.add(fragment1);
        arrayList.add(fragment2);
        arrayList.add(fragment3);
        arrayList.add(fragment4);
        radioButtons=new RadioButton[rg.getChildCount()];
        for (int i = 0; i < radioButtons.length; i++) {
            radioButtons[i]= (RadioButton) rg.getChildAt(i);
        }
        manager=getSupportFragmentManager();
        FragmentTransaction fragmentTransaction=manager.beginTransaction();
        fragmentTransaction.add(R.id.main_layout,arrayList.get(0));
        fragmentTransaction.commit();
        radioButtons[0].setChecked(true);
        rg.setOnCheckedChangeListener(this);

    }

    private void initView() {
        rg = (RadioGroup) findViewById(R.id.rg);
    }

    @Override
    public void onCheckedChanged(RadioGroup group, int checkedId) {
        FragmentTransaction transaction=manager.beginTransaction();
        for (int i = 0; i < radioButtons.length; i++) {
            if (radioButtons[i].getId()==checkedId){
                if (arrayList.get(i).isAdded()){
                    transaction.show(arrayList.get(i)).hide(arrayList.get(count)).commit();
                }else {
                    transaction.add(R.id.main_layout,arrayList.get(i)).hide(arrayList.get(count)).commit();
                }
                count=i;
            }
        }

    }
}

//布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.douyu.main.MainActivity">
    <FrameLayout
        android:layout_weight="1"
        android:id="@+id/main_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </FrameLayout>

    <RadioGroup
        android:id="@+id/rg"
        android:background="@android:color/white"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="56dp">

        <RadioButton
            android:textColor="@color/textcolor"
            android:gravity="center"
            android:text="首页"
            android:layout_marginTop="2dp"
            android:button="@null"
            android:drawableTop="@drawable/homepage_item"
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        <RadioButton
            android:textColor="@color/textcolor"
            android:gravity="center"
            android:text="分类"
            android:layout_marginTop="2dp"
            android:drawableTop="@drawable/classify_item"
            android:button="@null"
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <RadioButton
            android:textColor="@color/textcolor"
            android:gravity="center"
            android:text="关注"
            android:layout_marginTop="2dp"
            android:drawableTop="@drawable/attention_item"
            android:button="@null"
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <RadioButton
            android:textColor="@color/textcolor"
            android:gravity="center"
            android:text="鱼吧"
            android:layout_marginTop="2dp"
            android:drawableTop="@drawable/bar_item"
            android:button="@null"
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <RadioButton
            android:textColor="@color/textcolor"
            android:gravity="center"
            android:text="我的"
            android:layout_marginTop="2dp"
            android:layout_weight="1"
            android:drawableTop="@drawable/user_item"
            android:button="@null"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

    </RadioGroup>

</LinearLayout>

//text文字颜色,在res下创建color文件夹
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:color="@android:color/black" android:state_checked="false"/>
    <item android:color="#ff6600" android:state_checked="true"/>

</selector>