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diff --git a/docs/html/preview/material/ui-widgets.jd b/docs/html/preview/material/ui-widgets.jd new file mode 100644 index 0000000..f18bff9 --- /dev/null +++ b/docs/html/preview/material/ui-widgets.jd @@ -0,0 +1,197 @@ +page.title=UI Widgets + +@jd:body + +<div id="qv-wrapper"> +<div id="qv"> +<h2>In this document</h2> +<ol> + <li><a href="#recyclerview">RecyclerView</a></li> + <li><a href="#cardview">CardView</a></li> +</ol> +</div> +</div> + +<p>The support library in the Android L Developer Preview contains two new widgets, +<code>RecyclerView</code> and <code>CardView</code>. Use these widgets to show complex lists +and cards in your app. These widgets have material design styles and animations by default.</p> + + +<h2 id="recyclerview">RecyclerView</h2> + +<p><code>RecyclerView</code> is a more advanced version of <code>ListView</code>. This widget is +a container for large sets of views that can be recycled and scrolled very efficiently. Use the +<code>RecyclerView</code> widget when you have lists with elements that change dynamically.</p> + +<p><code>RecyclerView</code> is easy to use, because it provides:</p> + +<ul> + <li>A set of layout managers for positioning items</li> + <li>Default animations for common item operations</li> +</ul> + +<p>You also have the flexibility to define custom layout managers and animations for this +widget.</p> + +<p>To use the <code>RecyclerView</code> widget, you have to specify an adapter and a layout +manager. An <strong>adapter</strong> provides a binding from a dataset to views that are displayed +within a <code>RecyclerView</code>. For example, if your dataset is an array of strings displayed +as <code>TextView</code> items, the layout manager asks the adapter to: +</p> + +<ul> + <li>Set the text of an existing <code>TextView</code> to one of the strings in the dataset</li> + <li>Create new <code>TextView</code> objects</li> + <li>Determine the size of the dataset</li> +</ul> + +<p>To create an adapter, you extend the <code>RecyclerView.Adapter</code> class. The details of +the implementation depend on the specifics of your dataset and the type of views. Fore more +information, see the examples below.</p> + +<img src="/preview/material/images/RecyclerView.png" alt="" id="figure1" style="width:550px"/> +<p class="img-caption"> + <strong>Figure 1</strong> - The <code>RecyclerView</code> widget. +</p> + +<p>A <strong>layout manager</strong> positions item views inside a <code>RecyclerView</code> and +determines when to reuse item views that are no longer visible to the user. To reuse (or +<em>recycle</em>) a view, a layout manager may ask the adapter to replace the content of the +view with a different element from the dataset. Recycling views in this manner improves +performance by avoiding the creation of unnecessary views or performing expensive +<code>findViewById</code> lookups. +</p> + +<p><code>RecyclerView</code> provides two layout managers you can use:</p> + +<ul> + <li><code>LinearLayoutManager</code> shows the items in a vertically scrolling list.</li> + <li><code>GridLayoutManager</code> shows the items in a rectangular grid.</li> +</ul> + +<p>To create a custom layout, you extend the <code>RecyclerView.LayoutManager</code> class.</p> + +<h3>Examples</h3> + +<p>To include a <code>RecyclerView</code> in your layout:</p> + +<pre> +<!-- A RecyclerView with some commonly used attributes --> +<android.support.v7.widget.RecyclerView + android:id="@+id/my_recycler_view" + android:scrollbars="vertical" + android:layout_width="match_parent" + android:layout_height="match_parent"/> +</pre> + +<p>To get the <code>RecyclerView</code> object in your activity:</p> + +<pre> +public class MyActivity extends ActionBarActivity { + private RecyclerView mRecyclerView; + private RecyclerView.Adapter mAdapter; + private RecyclerView.LayoutManager mLayoutManager; + + @Override + protected void onCreate(Bundle savedInstanceState) { + super.onCreate(savedInstanceState); + setContentView(R.layout.my_activity); + mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view); + + // improve performance if the size is fixed + mRecyclerView.setHasFixedSize(true); + + // use a linear layout manager + mLayoutManager = new LinearLayoutManager(this); + mRecyclerView.setLayoutManager(mLayoutManager); + + // specify an adapter (see also next example) + mAdapter = new MyAdapter(myDataset); + mRecyclerView.setAdapter(mAdapter); + } + ... +} +</pre> + +<p>To create a simple adapter:</p> + +<pre> +public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> { + private String[] mDataset; + + // Provide a reference to the type of views that you are using + // (custom viewholder) + public static class ViewHolder extends RecyclerView.ViewHolder { + public TextView mTextView; + public ViewHolder(TextView v) { + super(v); + mTextView = v; + } + } + + // Provide a suitable constructor (depends on the kind of dataset) + public MyAdapter(String[] myDataset) { + mDataset = myDataset; + } + + // Create new views (invoked by the layout manager) + @Override + public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, + int viewType) { + // create a new view + View v = new TextView(parent.getContext()); + // set the view's size, margins, paddings and layout parameters + ... + ViewHolder vh = new ViewHolder(v); + return vh; + } + + // Replace the contents of a view (invoked by the layout manager) + @Override + public void onBindViewHolder(ViewHolder holder, int position) { + // - get element from your dataset at this position + // - replace the contents of the view with that element + holder.mTextView.setText(mDataset[position]); + + } + + // Return the size of your dataset (invoked by the layout manager) + @Override + public int getItemCount() { + return mDataset.length; + } +} +</pre> + + +<h2 id="cardview">CardView</h2> + +<p><code>CardView</code> extends the <code>FrameLayout</code> class and lets you show information +inside a card with optional rounded corners:</p> + +<ul> + <li>To set the corner radius in your layouts, use the <code>android:cardCornerRadius</code> + attribute.</li> + <li>To set the corner radius in your code, use the <code>CardView.setRadius</code> method.</li> +</ul> + +<p>To set the background color of a card, use the <code>android:cardBackgroundColor</code> +attribute.</p> + +<p>To include a <code>CardView</code> in your layout:</p> + +<pre> +<!-- A CardView that contains a TextView --> +<android.support.v7.widget.CardView + android:id="@+id/card_view" + android:layout_gravity="center" + android:layout_width="200dp" + android:layout_height="200dp" + card_view:cardCornerRadius="4dp"> + + <TextView + android:id="@+id/info_text" + android:layout_width="match_parent" + android:layout_height="match_parent" /> +</android.support.v7.widget.CardView> +</pre>
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