替換ViewPager中的Fragment - Replace Fragment inside a ViewPager

問題：

I'm trying to use Fragment with a ViewPager using the FragmentPagerAdapter . 我試圖使用片段與ViewPager使用FragmentPagerAdapter 。 What I'm looking for to achieve is to replace a fragment, positioned on the first page of the ViewPager , with another one. 我想要實現的是將位於ViewPager第一頁上的片段替換爲另一片段。

The pager is composed of two pages. 尋呼機由兩頁組成。 The first one is the FirstPagerFragment , the second one is the SecondPagerFragment . 第一個是FirstPagerFragment ，第二個是SecondPagerFragment 。 Clicking on a button of the first page. 單擊第一頁的按鈕。 I'd like to replace the FirstPagerFragment with the NextFragment. 我想用NextFragment替換FirstPagerFragment 。

There is my code below. 我的代碼如下。

public class FragmentPagerActivity extends FragmentActivity {

    static final int NUM_ITEMS = 2;

    MyAdapter mAdapter;
    ViewPager mPager;

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

        mAdapter = new MyAdapter(getSupportFragmentManager());

        mPager = (ViewPager) findViewById(R.id.pager);
        mPager.setAdapter(mAdapter);

    }


    /**
     * Pager Adapter
     */
    public static class MyAdapter extends FragmentPagerAdapter {
        public MyAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public int getCount() {
            return NUM_ITEMS;
        }

        @Override
        public Fragment getItem(int position) {

            if(position == 0) {
                return FirstPageFragment.newInstance();
            } else {
                return SecondPageFragment.newInstance();
            }

        }
    }


    /**
     * Second Page FRAGMENT
     */
    public static class SecondPageFragment extends Fragment {

        public static SecondPageFragment newInstance() {
            SecondPageFragment f = new SecondPageFragment();
            return f;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            //Log.d("DEBUG", "onCreateView");
            return inflater.inflate(R.layout.second, container, false);

        }
    }

    /**
     * FIRST PAGE FRAGMENT
     */
    public static class FirstPageFragment extends Fragment {

        Button button;

        public static FirstPageFragment newInstance() {
            FirstPageFragment f = new FirstPageFragment();
            return f;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            //Log.d("DEBUG", "onCreateView");
            View root = inflater.inflate(R.layout.first, container, false);
            button = (Button) root.findViewById(R.id.button);
            button.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    FragmentTransaction trans = getFragmentManager().beginTransaction();
                                    trans.replace(R.id.first_fragment_root_id, NextFragment.newInstance());
                    trans.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
                    trans.addToBackStack(null);
                    trans.commit();

                }

            });

            return root;
        }

        /**
     * Next Page FRAGMENT in the First Page
     */
    public static class NextFragment extends Fragment {

        public static NextFragment newInstance() {
            NextFragment f = new NextFragment();
            return f;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            //Log.d("DEBUG", "onCreateView");
            return inflater.inflate(R.layout.next, container, false);

        }
    }
}

...and here the xml files ...這裏是xml文件

fragment_pager.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical" android:padding="4dip"
        android:gravity="center_horizontal"
        android:layout_width="match_parent" android:layout_height="match_parent">

    <android.support.v4.view.ViewPager
            android:id="@+id/pager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1">
    </android.support.v4.view.ViewPager>

</LinearLayout>

first.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/first_fragment_root_id"
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent">

  <Button android:id="@+id/button"
     android:layout_width="wrap_content" android:layout_height="wrap_content"
     android:text="to next"/>

</LinearLayout>

Now the problem... which ID should I use in 現在問題是......我應該使用哪個ID

trans.replace(R.id.first_fragment_root_id, NextFragment.newInstance());

? ？

If I use R.id.first_fragment_root_id , the replacement works, but Hierarchy Viewer shows a strange behavior, as below. 如果我使用R.id.first_fragment_root_id ，則替換有效，但層次結構查看器顯示奇怪的行爲，如下所示。

At the beginning the situation is 一開始情況就是這樣

after the replacement the situation is 更換後的情況是

As you can see there is something wrong, I expect to find the same state shown as in the first picture after I replace the fragment. 正如您所看到的那樣，有一些問題，我希望在更換片段後找到與第一張圖片中顯示的狀態相同的狀態。

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解決方案：

參考一： https://stackoom.com/question/WPM4
參考二： Replace Fragment inside a ViewPager