Android中一个活动添加两个片段

Question

我想在Android的一个活动中添加两个片段。但在加法时，它给出了错误；

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context="com.example.namal.fragments.MainActivity">


    <fragment
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:name="com.example.namal.fragments.Pie1"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="37dp"
        android:layout_marginBottom="20dp"
        android:id="@+id/fragment" />

    <fragment
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:name="com.example.namal.fragments.Pie2"
        android:layout_below="@+id/fragment"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:id="@+id/fragment2" />
</RelativeLayout>

public class MainActivity extends AppCompatActivity {

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

        Pie1 firstFragment = new Pie1();

        FragmentManager fm = getSupportFragmentManager();
        Fragment fragment = fm.findFragmentById(R.id.activity_main);

        if (fragment == null) {
            fm.beginTransaction()
                    .add(R.id.fragment, firstFragment)
                    .commit();

            Pie2 secondFragment = new Pie2();
            fm.beginTransaction()
                    .add(R.id.fragment2, secondFragment)
                    .commit();
        }
    }
}

片段的布局1

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorAccent"
   >

    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/hello_blank_fragment" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="hello_blank_fragment 2" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="hello_blank_fragment 3" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="hello_blank_fragment 4" />

</FrameLayout>

片段2的布局

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorPrimaryDark"
    tools:context="com.example.namal.fragments.Pie2">

    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="hello_blank_fragment 5" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="hello_blank_fragment 6" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="hello_blank_fragment 7" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="hello_blank_fragment 8" />

</FrameLayout>

Answer 1

Caused by: java.lang.RuntimeException:
    com.example.namal.fragments.MainActivity@1602e5b8 must implement OnFragmentInteractionListener
    at com.example.namal.fragments.Pie1.onAttach(Pie1.java:83)

您需要使活动实现OnFragmentInteractionListener

public class MainActivity extends AppCompatActivity implements OnFragmentInteractionListener {