Question

我正在尝试实现一个ViewPager，但是目前它在一个屏幕上呈现所有视图，当移动到下一个屏幕时它是空的，它包含所有内容。我有一种感觉它与碎片中的片段有关，但我无法弄明白。

在下面的屏幕截图中，您可以看到它：

enter image description here

这是代码的（部分）。（ArticlePagerAdapter只是用于查找特定对象类型的proto的实现）。

public abstract class PrototypePagerActivity<T extends GenericModel> extends BaseActivity {

    PrototypePagerAdapter mAdapter;
    ViewPager mPager;

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

        long categoryId = -1;
        int articlePos = 0;

        Bundle extras = getIntent().getExtras();
        if (extras != null) {
            //if (extras.containsKey("articleId")) articleId = extras.getInt("articleId");
            if (extras.containsKey("position")) articlePos = extras.getInt("position");
            if (extras.containsKey("categoryId")) categoryId = extras.getLong("categoryId");
        }
        mAdapter = new ArticlePagerAdapter(categoryId,getSupportFragmentManager());
        mPager = (ViewPager) findViewById(R.id.protoPager);
        mPager.setAdapter(mAdapter);

        mPager.setCurrentItem(articlePos);
    }

}

public abstract class PrototypePagerAdapter<T extends GenericModel> extends FragmentPagerAdapter {

    @Override
    public Fragment getItem(int position) {
        try {
            T object = getObjectForPosition(position);

            ArticleFragment articleFragment = new ArticleFragment();
            Bundle args = new Bundle();
            args.putLong("articleId", object.getId());
            articleFragment.setArguments(args);
            return articleFragment;
        } catch (Exception e) {
            Log.w(iDomsAndroidApp.TAG, "Problem getting the object instance for pages", e);
            return null;
        }
    }

    public abstract T getObjectForPosition(int position) throws Exception;

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

    public abstract int requestObjectCount();

}

public class ArticleFragment extends Fragment {   
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_article, container, false);

        if (savedInstanceState == null) {
            getFragmentManager().beginTransaction()
                    .add(R.id.content_fragment, new PlaceholderFragment())
                    .commit();
        }

        ArticleHeaderFragment articleHeaderFragment = new ArticleHeaderFragment();
        articleHeaderFragment.setArguments(getArguments());
        getFragmentManager().beginTransaction().add(R.id.header_fragment, articleHeaderFragment).commit();

        ArticleContentFragment articleContentFragment = ArticleContentFragment.newInstance();
        articleContentFragment.setArguments(getArguments());
        getFragmentManager().beginTransaction().add(R.id.content_fragment, articleContentFragment).commit();

        return view;
    }    
}

activity_proto_pager.xml：

<?xml version="1.0" encoding="utf-8"?>

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

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

fragment_article.xml：

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <ImageView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/imageView"
        android:src="@drawable/background"
        android:scaleType="centerCrop"
        android:contentDescription="@string/background_image"
        android:alpha="0.6" />

    <ScrollView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:scrollbars="vertical">

        <LinearLayout
            android:orientation="vertical"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content">

            <FrameLayout
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/audio_control_fragment" />

            <FrameLayout
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/header_fragment" />

            <FrameLayout
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/content_fragment" />
        </LinearLayout>
    </ScrollView>


</RelativeLayout>

fragment_article_header.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/list_background_overlay"
    android:layout_centerInParent="true"
    tools:context="org.idoms.iDomsAndroid.fragments.ArticleHeaderFragment">

    <org.idoms.iDomsAndroid.views.ResizableImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:maxHeight="200dp"
        android:id="@+id/article_imageView"
        android:layout_gravity="center_horizontal"
        android:scaleType="centerCrop" />

</LinearLayout>

Answer 1

你应该替换片段而不是添加。

所以，而不是.add(...)使用.replace(....)

<强>更新

您正在另外两个地方添加片段。使用articleHeaderFragment和articleContentFragment执行上述步骤。你可以在else部分添加第二部分代码（如果是根据你的逻辑）

更新2

你也应该重温你的逻辑。与下面的代码一样，您在R.id.content_fragment中添加了两个片段。替换可以在这里提供帮助，但您的代码将是多余的

if (savedInstanceState == null) {
     getFragmentManager().beginTransaction()
     .add(R.id.content_fragment, new PlaceholderFragment())
     .commit();
}

ArticleContentFragment articleContentFragment = ArticleContentFragment.newInstance();
articleContentFragment.setArguments(getArguments());
getFragmentManager().beginTransaction().add(R.id.content_fragment, articleContentFragment).commit();

ViewPager将视图显示在彼此之上

1 个答案: