将 fragment 添加到 Activity 类时发生Android冲突

Question

我已经将我的 fragments 类定义为

import android.support.v4.app.Fragment;
public class UserAccountDetailsFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.user_account_details_fragment, container, false);

}}

我将我的 Activity 定义为

   import android.support.v4.app.FragmentActivity;
   public class HomeScreenActivity extends FragmentActivity {
    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home_screen);
    UserAccountDetailsFragment userAccDetailsFrag = new   UserAccountDetailsFragment();

     android.app.FragmentManager fragmentManager = getFragmentManager();
      android.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
      fragmentTransaction.add(R.id.fragments, userAccDetailsFrag );
      fragmentTransaction.commit();
    }

问题是我无法添加 fragment 。它说 UserAccountDetailsFragment 应该成为一个 fragment 。但是那个类已经扩展了 fragment 。我在这里缺少什么？

XML---

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".HomeScreenActivity" >

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

<fragment 
    android:id="@+id/fragments"
      android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world"
    />

Answer 1

您正在使用 support.v4 包。
你应该试试下面的方法:

FragmentManager manager=getSupportFragmentManager();
FragmentTransaction transaction=manager.beginTransaction();