Question

我的主要目标是在每一行中创建一个listview，每个页面都有一个“ImageWordFragment”，它包含一个Imageview。

请不要告诉我不要在列表视图中使用viewpager。许多应用程序都在这样做，只是帮助实现我的目标。

我尝试设置“setId（）”，但它在“getView”函数中的ViewPager变量中提示出一个null异常。

问题是第一个viewpager在listview的第一行中起作用。但其余部分则没有。

这是“fragment_word_image.xml”的xml：

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

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

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/background_grey"/>

</LinearLayout>

这是“item_word.xml”的xml：

<LinearLayout
        android:id="@+id/moreInfo"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <android.support.v4.view.ViewPager
            android:id="@+id/viewPager"
            android:layout_width="match_parent"
            android:layout_height="200dp" />

    </LinearLayout>

这是适配器：

public class WordAdapter extends BaseAdapter {

    private AppCompatActivity activity;
    private LayoutInflater inflater;
    private List<Word> wordItems;

    public WordAdapter(AppCompatActivity activity, List<Word> wordItems) {
        this.activity = activity;
        this.wordItems = wordItems;
    }

    @Override
    public int getCount() {
        return wordItems.size();
    }

    @Override
    public Word getItem(int position) {
        return wordItems.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        if (inflater == null) {
            inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }

        if (convertView == null) {
            convertView = inflater.inflate(R.layout.item_word, parent, false);
        }

        FrameLayout container = (FrameLayout) convertView.findViewById(R.id.container);
        TextView type = (TextView) convertView.findViewById(R.id.type);
        TextView name = (TextView) convertView.findViewById(R.id.name);
        ImageView progress = (ImageView) convertView.findViewById(R.id.progress);

        final LinearLayout moreInfo = (LinearLayout) container.findViewById(R.id.moreInfo);
        ViewPager pager = (ViewPager) convertView.findViewById(R.id.viewPager);

        // Getting word data
        final Word w = wordItems.get(position);

        //Pager
        WordPagerAdapter adapter = new WordPagerAdapter(activity.getSupportFragmentManager(), activity, pager);

        Bundle args1 = new Bundle();
        args1.putString(ImageWordFragment.ARG_LINK, w.getImage());
        adapter.addTab(R.string.title_section1, ImageWordFragment.class, args1);

        Bundle args2 = new Bundle();
        args2.putString(ImageWordFragment.ARG_LINK, w.getImage());
        adapter.addTab(R.string.title_section1, ImageWordFragment.class, args2);

        Bundle args3 = new Bundle();
        args3.putString(ImageWordFragment.ARG_LINK, w.getImage());
        adapter.addTab(R.string.title_section1, ImageWordFragment.class, args3);

        //Notify Changes
        adapter.notifyTabsChanged();

        return convertView;
    }

    private class WordPagerAdapter extends FragmentStatePagerAdapter {

        private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();

        private final Context mContext;

        private final FragmentManager mFragmentManager;

        private final ViewPager mViewPager;

        final class TabInfo {

            private final Class<?> mClass;

            private final Bundle mArgs;

            private final int mTitleRes;

            TabInfo(Class<?> fragmentClass, Bundle args, int titleRes) {
                mClass = fragmentClass;
                mArgs = args;
                mTitleRes = titleRes;
            }
        }

        public WordPagerAdapter(FragmentManager fm, Context context, ViewPager pager) {
            super(fm);
            mFragmentManager = fm;
            mContext = context;

            //Setup view pager
            mViewPager = pager;
            mViewPager.setAdapter(this);
        }

        public void addTab(int titleRes, Class<?> fragmentClass, Bundle args) {
            mTabs.add(new TabInfo(fragmentClass, args, titleRes));
        }

        public void notifyTabsChanged() {
            notifyDataSetChanged();
        }

        public void setCurrentItem(int position) {
            mViewPager.setCurrentItem(position);
        }

        public void setOffscreenPageLimit(int pages) {
            mViewPager.setOffscreenPageLimit(pages);
        }

        @Override
        public Fragment getItem(int position) {
            TabInfo tab = mTabs.get(position);
            return Fragment.instantiate(mContext, tab.mClass.getName(), tab.mArgs);
        }

        @Override
        public int getCount() {
            return mTabs.size();
        }
    }

}

Thsi是片段：

public class ImageWordFragment extends Fragment {

    public static final String ARG_LINK = "ARG_LINK";

    @InjectView(R.id.imageView)
    ImageView imageView;

    String imageUrl;

    public ImageWordFragment() {

    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        imageUrl = getArguments().getString(ARG_LINK);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_word_image, container, false);

        ButterKnife.inject(this, rootView);

        new ImageLoadTask(imageUrl, imageView);

        return rootView;
    }

}

Answer 1

一些实验表明这可能是由于ViewPager所有具有相同ID（来自XML）引起的。您是否尝试使用View.generateViewId()在运行时生成ID？

Listview中的ViewPager用于所有行

1 个答案: