Recycler 3.0.0

WARNING

This is documentation for legacy versions. For the most current version click here.

This artifact allows displaying markdown in a set of Android widgets inside a RecyclerView. Can be useful when displaying lengthy markdown content or displaying certain markdown blocks inside specific widgets.

// create an adapter that will use a TextView for each block of markdown
// `createTextViewIsRoot` accepts a layout in which TextView is the root view
final MarkwonAdapter adapter = 
        MarkwonAdapter.createTextViewIsRoot(R.layout.adapter_default_entry);

// `create` method accepts a layout with TextView and ID of a TextView
// which allows wrapping a TextView inside another widget or combine with other widgets
final MarkwonAdapter adapter = 
        MarkwonAdapter.create(R.layout.adapter_default_entry, R.id.text_view);

// initialize RecyclerView (LayoutManager, Decorations, etc)
final RecyclerView recyclerView = obtainRecyclerView();

// set adapter
recyclerView.setAdapter(adapter);

// obtain an instance of Markwon (register all required plugins)
final Markwon markwon = obtainMarkwon();

// set markdown to be displayed
adapter.setMarkdown(markwon, "# This is markdown!");

// NB, adapter does not handle updates on its own, please use
// whatever method appropriate for you.
adapter.notifyDataSetChanged();

Initialized adapter above will use a TextView for each markdown block. In order to tell adapter to render certain blocks differently a builder can be used. For example, let's render FencedCodeBlock inside a HorizontalScrollView:

// we still need to have a _default_ entry
final MarkwonAdapter adapter =
        MarkwonAdapter.builderTextViewIsRoot(R.layout.adapter_default_entry)
                .include(FencedCodeBlock.class, new FencedCodeBlockEntry())
                .build();

where FencedCodeBlockEntry is:

public class FencedCodeBlockEntry extends MarkwonAdapter.Entry<FencedCodeBlock, FencedCodeBlockEntry.Holder> {

    @NonNull
    @Override
    public Holder createHolder(@NonNull LayoutInflater inflater, @NonNull ViewGroup parent) {
        return new Holder(inflater.inflate(R.layout.adapter_fenced_code_block, parent, false));
    }

    @Override
    public void bindHolder(@NonNull Markwon markwon, @NonNull Holder holder, @NonNull FencedCodeBlock node) {
        markwon.setParsedMarkdown(holder.textView, markwon.render(node));
    }

    public static class Holder extends MarkwonAdapter.Holder {

        final TextView textView;

        public Holder(@NonNull View itemView) {
            super(itemView);

            this.textView = requireView(R.id.text_view);
        }
    }
}

and its layout (R.layout.adapter_fenced_code_block):

<?xml version="1.0" encoding="utf-8"?>
<HorizontalScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:fillViewport="true"
    android:paddingLeft="16dip"
    android:paddingRight="16dip"
    android:scrollbarStyle="outsideInset">

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#0f000000"
        android:fontFamily="monospace"
        android:lineSpacingExtra="2dip"
        android:paddingLeft="16dip"
        android:paddingTop="8dip"
        android:paddingRight="16dip"
        android:paddingBottom="8dip"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:textSize="14sp" />

</HorizontalScrollView>

As we apply styling to FencedCodeBlock manually, we no longer need Markwon to apply styling spans for us, so Markwon initialization could be:

final Markwon markwon = Markwon.builder(context)
        // your other plugins
        .usePlugin(new AbstractMarkwonPlugin() {
            @Override
            public void configureVisitor(@NonNull MarkwonVisitor.Builder builder) {
                builder.on(FencedCodeBlock.class, (visitor, fencedCodeBlock) -> {
                    // we actually won't be applying code spans here, as our custom view will
                    // draw background and apply mono typeface
                    //
                    // NB the `trim` operation on literal (as code will have a new line at the end)
                    final CharSequence code = visitor.configuration()
                            .syntaxHighlight()
                            .highlight(fencedCodeBlock.getInfo(), fencedCodeBlock.getLiteral().trim());
                    visitor.builder().append(code);
                });
            }
        })
        .build();

Previously we have created a FencedCodeBlockEntry but all it does is apply markdown to a TextView. For such a case there is a SimpleEntry that could be used instead:

final MarkwonAdapter adapter =
        MarkwonAdapter.builderTextViewIsRoot(R.layout.adapter_default_entry)
                .include(FencedCodeBlock.class, SimpleEntry.create(R.layout.adapter_fenced_code_block, R.id.text_view))
                .build();

TIP

SimpleEntry also takes care of caching parsed markdown. So each node will be parsed only once and each subsequent adapter binding call will reuse previously cached markdown.

Tables

There is a standalone artifact that adds support for displaying markdown tables natively via TableLayout. Please refer to its documentation

# Recycler 3.0.0

Recycler 3.0.0