RecyclerView中的RecyclerVIew

Question

我想创建嵌套的RecyclerViews，但问题是只显示了父对象。

父适配器

public class SectionsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    Context mContext;
    List<Section> mSections;

    public SectionsAdapter(Context context, List<Section> sections) {
        mContext = context;
        mSections = sections;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_section, parent, false);
        return new SectionViewHolder(view);
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int pos) {
        Section section = mSections.get(pos);
        if (holder instanceof SectionViewHolder) {
            SectionViewHolder sectionVH = (SectionViewHolder) holder;
            sectionVH.mTitle.setText(section.getTitle());
            LinearLayoutManager manager = new LinearLayoutManager(mContext);
            sectionVH.mPreferences.setLayoutManager(manager);
            PreferencesAdapter preferencesAdapter = new PreferencesAdapter(mContext, section.getPreferences());
            sectionVH.mPreferences.setAdapter(preferencesAdapter);
            sectionVH.mPreferences.getAdapter().notifyDataSetChanged();
        }
    }

    @Override
    public int getItemViewType(int pos) {
        return 0;
    }

    @Override
    public int getItemCount() {
        return mSections.size();
    }
}

子适配器

public class PreferencesAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    public static final int VIEW_BOOLEAN = 0;
    public static final int VIEW_INT = 1;

    Context mContext;
    List<Preference> mPreferences;

    public PreferencesAdapter(Context context, List<Preference> preferences) {
        mContext = context;
        mPreferences = preferences;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view;
        switch (viewType) {
            default:
                view = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_preference_boolean, parent, false);
                return new BooleanPreferenceViewHolder(view);
        }
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int pos) {
        Preference preference = mPreferences.get(pos);
        if (holder instanceof BooleanPreferenceViewHolder) {
            BooleanPreferenceViewHolder booleanPreferenceVH = (BooleanPreferenceViewHolder) holder;
            booleanPreferenceVH.mPreferenceTitle.setText(preference.getTitle());
            booleanPreferenceVH.mPreferenceExplanation.setText(preference.getExplanation());
            booleanPreferenceVH.mBooleanSwitch.setChecked((Boolean) preference.getValue());
        }
    }

    @Override
    public int getItemViewType(int pos) {
        return VIEW_BOOLEAN;
    }

    @Override
    public int getItemCount() {
        return mPreferences.size();
    }
}

父视图框

public class SectionViewHolder extends RecyclerView.ViewHolder {

    public TextView mTitle;
    public RecyclerView mPreferences;

    public SectionViewHolder(View v) {
        super(v);
        mTitle = (TextView) v.findViewById(R.id.sectionTitle);
        mPreferences = (RecyclerView) v.findViewById(R.id.preferences);
    }

}

子视图框

public class BooleanPreferenceViewHolder extends RecyclerView.ViewHolder {

    public TextView mPreferenceTitle;
    public TextView mPreferenceExplanation;
    public Switch mBooleanSwitch;

    public BooleanPreferenceViewHolder(View v) {
        super(v);
        mPreferenceTitle = (TextView) v.findViewById(R.id.preferenceTitle);
        mBooleanSwitch = (Switch) v.findViewById(R.id.booleanSwitch);
        mPreferenceExplanation = (TextView) v.findViewById(R.id.preferenceExplanation);
    }

}

所以我注意到它只显示了父级标题，它的回收器视图是空的。子onBindViewHolder方法也未调用。

Answer 1

您只需使用一个RecyclerView，适当地覆盖getItemViewType方法，就可以实现您想要的结果。您可以看到一个示例here。

下面是将Section、Preference和BooleanPreferenceViewHolder类与库SectionedRecyclerViewAdapter一起使用的示例。

首先创建一个section类：

class MySection extends StatelessSection {

    String title;
    List<Preference> mPreferences;

    public MySection(String title, List<Preference> preferences) {
        // call constructor with layout resources for this Section header, footer and items 
        super(R.layout.section_header, R.layout.section_footer,  R.layout.section_item);

        this.title = title;
        this.mPreferences = preferences;
    }

    @Override
    public int getContentItemsTotal() {
        return mPreferences.size(); // number of items of this section
    }

    @Override
    public RecyclerView.ViewHolder getItemViewHolder(View view) {
        // return a custom instance of ViewHolder for the items of this section
        return new BooleanPreferenceViewHolder(view);
    }

    @Override
    public void onBindItemViewHolder(RecyclerView.ViewHolder holder, int position) {
        BooleanPreferenceViewHolder itemHolder = (BooleanPreferenceViewHolder) holder;

        // bind your view here
        itemHolder.mPreferenceExplanation.setText(mPreference.get(position).getExplanation());
    }

    @Override
    public RecyclerView.ViewHolder getHeaderViewHolder(View view) {
        return new SimpleHeaderViewHolder(view);
    }

    @Override
    public void onBindHeaderViewHolder(RecyclerView.ViewHolder holder) {
        MyHeaderViewHolder headerHolder = (MyHeaderViewHolder) holder;

        // bind your header view here
        headerHolder.tvItem.setText(title);
    }
}

然后使用您的Sections设置RecyclerView

// Create an instance of SectionedRecyclerViewAdapter 
SectionedRecyclerViewAdapter sectionAdapter = new SectionedRecyclerViewAdapter();

MySection section1 = new MySection(mSections.get(0).getTitle(), mSections.get(0).getPreferences());
MySection section2 = new MySection(mSections.get(1).getTitle(), mSections.get(1).getPreferences());

// Add your Sections
sectionAdapter.addSection(section1);
sectionAdapter.addSection(section2);

// Set up your RecyclerView with the SectionedRecyclerViewAdapter
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setAdapter(sectionAdapter);