Android:Fragment和ViewPager总是在第一个位置启动

我为我的Android应用程序使用主/详细设计。如果我在ItemListActivity中单击listview中的某个项目，则该位置将指定给我的ItemDetailActivity。这一个实现了ViewPager和FragmentStatePagerAdapter。所以我想在细节视图之间滑动

我不知道如何告诉ViewPager从所需的位置开始（ItemListActivity中的整数）。我的ViewPager始终从列表的位置0开始，无论我在列表上单击了哪个位置

这是我的代码：

ItemDetailActivity

public class ItemDetailActivity extends FragmentActivity {

    RSSFeed feed;
    int pos;
    private static List<Fragment> fragments;

    /**
     * The pager widget, which handles animation and allows swiping horizontally to access previous
     * and next wizard steps.
     */
    private ViewPager mPager;

    /**
     * The pager adapter, which provides the pages to the view pager widget.
     */
    private PagerAdapter mPagerAdapter;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // define layout of this activity
        setContentView(R.layout.activity_item_detail);

        // Get the feed object and the position from the Intent
        feed = (RSSFeed) getIntent().getExtras().get("feed");
        //position of the clicked item from the list
        pos = getIntent().getExtras().getInt("pos");

        //create all 20 ItemDetailFragments
        fragments = new ArrayList<Fragment>();
         for(int i=0; i<=20; i++)
                fragments.add(ItemDetailFragment.create(i ,feed));

        // Instantiate a ViewPager and a PagerAdapter.
        mPager = (ViewPager) findViewById(R.id.viewpager);
        mPagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());
        mPager.setAdapter(mPagerAdapter);
        mPager.setPageTransformer(true, new ZoomOutPageTransformer());
    }

    @Override
    public void onBackPressed() {
        if (mPager.getCurrentItem() == 0) {
            // If the user is currently looking at the first step, allow the system to handle the
            // Back button. This calls finish() on this activity and pops the back stack.
            super.onBackPressed();
        } else {
            // Otherwise, select the previous step.
            mPager.setCurrentItem(mPager.getCurrentItem() - 1);
        }
    }

    /**
     * A simple pager adapter that represents ItemDetailFragment objects, in
     * sequence.
     * 
     * Creates a class that extends the FragmentStatePagerAdapter abstract class and
     * implements the getItem() method to supply instances of ScreenSlidePageFragment
     * as new pages. The pager adapter also requires that you implement the getCount()
     * method, which returns the amount of pages the adapter will create. 
     */
    private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {

        public ScreenSlidePagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int page_number) {
            return fragments.get(page_number);
        }

        @Override
        public int getCount() {
            //get the count of items in the feed
            return feed.getItemCount();
        }
    }

活动项目详细信息.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/lib/com.google.ads"
    android:id="@+id/main_item_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

   <android.support.v4.view.ViewPager
     android:id="@+id/viewpager"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent" />

    <FrameLayout
        android:id="@+id/item_detail_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/adView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        tools:context=".ItemDetailActivity"
        tools:ignore="MergeRootFrame" >

    </FrameLayout>

所以现在我可以把所有的项目都列出来，但它总是从第一个项目开始。我想从我在listview中单击的项目开始

---

我该怎么做呢？

您实际上已经在使用您的

onBackPressed（）方法中需要使用的方法了。

方法：

mPager.setCurrentItem(mPager.getCurrentItem() - 1);

---

只需在包中传递初始位置，然后在设置时调用此方法。

根据文档，您只需使用

mPager.setCurrentItem(pos);

---

您看过viewpager的文档了吗？非常感谢你的工作。请将其作为答案发布，我可以将其标记为解决方案

mPager.setCurrentItem(pos);