Question

我已经阅读了很多关于这个问题的相关问题。然而，他们都没有得到回答。我正在尝试向ViewPager中的每一行添加ListView，其中寻呼机中有两个布局。我认为这是可行的，因为 SwipeListView 。

现在我已经实现了它。但是，显示空白页面，中间有一条线。没有出现任何行。

Enter image description here

这是我的代码：

MainActivity + ArrayAdapter

public class MainActivity extends Activity {

    ListView list;
    String[] heros;

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

        heros = getResources().getStringArray(R.array.heros);

        list = (ListView) findViewById(R.id.listView1);
        list.setAdapter(new CustomAdapter(this, heros));
    }

    public class CustomAdapter extends ArrayAdapter<String>
    {
        String[] heros;
        Context context;
        public CustomAdapter(Context context, String[] heros) {
            super(context, R.layout.pager_item_list, R.id.listView1, heros);
            // TODO Auto-generated constructor stub
            this.heros = heros;
            this.context = context;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View row = inflater.inflate(R.layout.pager_item_list, parent, false);

            Log.d("how many times", "I really don't know how it should be");

            ViewPager pager = (ViewPager) row.findViewById(R.id.pager);
            pager.setId(position);
            pager.setAdapter(new PagerCustomAdapter());

            pager.setCurrentItem(0);

            return row;
        }
    }
}

这是我的pageAdapter

public class PagerCustomAdapter extends PagerAdapter{
    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return 2;
    }

    @Override
    public Object instantiateItem(View container, int position) {
        // TODO Auto-generated method stub

        LayoutInflater inflater = (LayoutInflater) container.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        int id = 0;

        Log.d("I am in pagerAdater", "I am here, dammit!");

        switch(position)
        {
            case 0:
                id = R.layout.fragment_top_item;
                break;
            case 1:
                id = R.layout.fragment_bottom_item;
                break;
        }
        View view = inflater.inflate(id, null);
        ((ViewPager)container).addView(view, 0);
        return view;
    }

    @Override
    public void destroyItem(View arg0, int arg1, Object arg2) {
        ((ViewPager) arg0).removeView((View) arg2);
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
        // TODO Auto-generated method stub
        return arg0 == ((View) arg1);
    }

    @Override
    public Parcelable saveState() {
        return null;
    }

}

我试过了pagerAdapter＆amp; FragmentPagerAdapter并且两者都有相同的结果

我在getView()和instantiateItem()中添加了两条日志消息，两者都按预期在logcat中读取。 LogCat中既没有警告也没有错误。

我错过了什么？

更新

activity_main的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=".MainActivity" >

<ListView
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true" >
</ListView>

</RelativeLayout>

pager_item_list的XML

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

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

Answer 1

我不确定你想要实现什么..你想在事件发生时改变观点吗？比如当你点击它？或者你想要像SwipeListView一样的结果。

如果您想更改视图，则可以尝试使用ViewFlipper anc在事件发生时更改布局。但我不确定这是否是你想要的结果

Answer 2

在ListView行中使用时，ViewPager需要具有唯一的android：id（因为每行必须具有不同的id）。这是因为与ViewPager适配器关联的FragmentManager使用id以及存储片段的位置。这意味着如果你只是使用默认值，那么事情就会被覆盖。

下面是一个示例PagerAdapter，它允许您覆盖默认的makeFragmentName方法。

import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Parcelable;
import android.support.v13.app.FragmentCompat;
import android.support.v4.view.PagerAdapter;
import android.view.View;
import android.view.ViewGroup;

public abstract class TaggedFragmentPagerAdapter extends PagerAdapter {

    private final FragmentManager mFragmentManager;

    private FragmentTransaction mCurTransaction = null;

    private Fragment mCurrentPrimaryItem = null;

    public TaggedFragmentPagerAdapter(FragmentManager fm) {
        mFragmentManager = fm;
    }

    /**
     * Return the Fragment associated with a specified position.
     */
    public abstract Fragment getItem(int position);

    public String getItemTag(int position) {
        // Maintain backward compatibility
        return String.valueOf(getItemId(position));
    }

    @Override
    public void startUpdate(ViewGroup container) {
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        if (mCurTransaction == null) {
            mCurTransaction = mFragmentManager.beginTransaction();
        }

        // Do we already have this fragment?
        String name = makeFragmentName(position, container.getId(), getItemTag(position));
        Fragment fragment = mFragmentManager.findFragmentByTag(name);
        if (fragment != null) {
            // FIXME : Start fix.
            if (!fragment.isDetached()) {
                mCurTransaction.detach(fragment);
            }
            // FIXME : End fix.
            mCurTransaction.attach(fragment);
        } else {
            fragment = getItem(position);
            mCurTransaction.add(container.getId(), fragment, name);
        }
        if (fragment != mCurrentPrimaryItem) {
            FragmentCompat.setMenuVisibility(fragment, false);
            FragmentCompat.setUserVisibleHint(fragment, false);
        }

        return fragment;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        if (mCurTransaction == null) {
            mCurTransaction = mFragmentManager.beginTransaction();
        }
        mCurTransaction.detach((Fragment) object);
    }

    @Override
    public void setPrimaryItem(ViewGroup container, int position, Object object) {
        Fragment fragment = (Fragment) object;
        if (fragment != mCurrentPrimaryItem) {
            if (mCurrentPrimaryItem != null) {
                FragmentCompat.setMenuVisibility(mCurrentPrimaryItem, false);
                FragmentCompat.setUserVisibleHint(mCurrentPrimaryItem, false);
            }
            if (fragment != null) {
                FragmentCompat.setMenuVisibility(fragment, true);
                FragmentCompat.setUserVisibleHint(fragment, true);
            }
            mCurrentPrimaryItem = fragment;
        }
    }

    @Override
    public void finishUpdate(ViewGroup container) {
        if (mCurTransaction != null) {
            mCurTransaction.commitAllowingStateLoss();
            mCurTransaction = null;
            mFragmentManager.executePendingTransactions();
        }
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return ((Fragment) object).getView() == view;
    }

    @Override
    public Parcelable saveState() {
        return null;
    }

    @Override
    public void restoreState(Parcelable state, ClassLoader loader) {
    }

    /**
     * Return a unique identifier for the item at the given position.
     *
     * <p> The default implementation returns the given position. Subclasses should override this method if the positions of items
     * can change. </p>
     *
     * @param position Position within this adapter
     * @return Unique identifier for the item at position
     */
    public long getItemId(int position) {
        return position;
    }

    protected String makeFragmentName(int position, int viewId, String tagName) {
        return "android:switcher:" + viewId + ":" + tagName;
    }
}

Answer 3

我遇到了类似的问题，我所做的是明确设置viewPager及其父级的高度。这对我有用。

<?xml version="1.0" encoding="utf-8"?>
  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="200dip"
    android:orientation="vertical" >

   <android.support.v4.view.ViewPager
      android:id="@+id/pager"
      android:layout_width="match_parent"
      android:layout_height="200dip" >
   </android.support.v4.view.ViewPager>
 </LinearLayout>

我不知道是否有更好的解决方案，但如果你有更好的解决方案，请发表评论！

ListView行项目中的ViewPager

3 个答案: