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diff --git a/docs/html/guide/topics/resources/layout-resource.jd b/docs/html/guide/topics/resources/layout-resource.jd new file mode 100644 index 0000000..a6b177f --- /dev/null +++ b/docs/html/guide/topics/resources/layout-resource.jd @@ -0,0 +1,224 @@ +page.title=Layout Resource +parent.title=Resource Types +parent.link=available-resources.html +@jd:body + +<div id="qv-wrapper"> + <div id="qv"> + <h2>See also</h2> + <ol> + <li><a href="{@docRoot}guide/topics/ui/declaring-layout.html">Declaring Layout</a></li> + </ol> + </div> +</div> + +<p>A layout resource defines the architecture for the UI in an Activity or a component of a UI.</p> + + +<dl class="xml"> + +<dt>file location:</dt> +<dd><code>res/layout/<em>filename</em>.xml</code><br/> +The filename will be used as the resource ID.</dd> + +<dt>compiled resource datatype:</dt> +<dd>Resource pointer to a {@link android.view.View} (or subclass) resource.</dd> + +<dt>resource reference:</dt> +<dd> +In Java: <code>R.layout.<em>filename</em></code><br/> +In XML: <code>@[<em>package</em>:]layout/<em>filename</em></code> +</dd> + +<dt>syntax:</dt> +<dd> +<pre class="stx"> +<?xml version="1.0" encoding="utf-8"?> +<<a href="#viewgroup-element"><em>ViewGroup</em></a> xmlns:android="http://schemas.android.com/apk/res/android" + android:id="@+id/<em>name</em>" + android:layout_height="@+id/<em>string_name</em>" + android:layout_width="@+id/<em>string_name</em>" + [<em>other attributes</em>] > + <<a href="#view-element"><em>View</em></a> + android:id="@+id/<em>name</em>" + android:layout_height="@+id/<em>string_name</em>" + android:layout_width="@+id/<em>string_name</em>" + [<em>other attributes</em>] > + <<a href="#requestfocus-element">requestFocus</a>/> + </<em>View</em>> + <<a href="#viewgroup-element"><em>ViewGroup</em></a> > + <<a href="#view-element"><em>View</em></a> /> + </<em>ViewGroup</em>> +</<em>ViewGroup</em>> +</pre> +<p class="note"><strong>Note:</strong> The root element can be either a +{@link android.view.ViewGroup} or a {@link android.view.View}, but there must be only +one root element and it must contain the {@code xmlns:android} attribute with the {@code android} +namespace as shown.</p> +</dd> + +<dt>elements:</dt> +<dd> + <dl class="tag-list"> + + <dt id="viewgroup-element"><code><ViewGroup></code></dt> + <dd>A container for other {@link android.view.View} elements. There are many + different kinds of {@link android.view.ViewGroup} objects and each one lets you + specify the layout of the child elements in different ways. Different kinds of + {@link android.view.ViewGroup} objects include {@link android.widget.LinearLayout}, + {@link android.widget.RelativeLayout}, and {@link android.widget.FrameLayout}. + <p>You should not assume that any derivation of {@link android.view.ViewGroup} + will accept nested {@link android.view.View}s. Some {@link android.view.ViewGroup}s + are implementations of the {@link android.widget.AdapterView} class, which determines + its children only from an {@link android.widget.Adapter}.</p> + <p class="caps">attributes:</p> + <dl class="atn-list"> + <dt><code>android:id</code></dt> + <dd><em>Resource name</em>. A unique resource name for the element, which you can +use to obtain a reference to the {@link android.view.ViewGroup} from your application. + The value takes the form: <code>"@+id/<em>name</em>"</code>. See more about the + <a href="#idvalue">value for {@code android:id}</a> below. + </dd> + <dt><code>android:layout_height</code></dt> + <dd><em>Dimension or keyword</em>. <strong>Required</strong>. The height for the group, as a +dimension value (or <a +href="more-resources.html#Dimension">dimension resource</a>) or a keyword ({@code "fill_parent"} +or {@code "wrap_content"}). See the <a href="#layoutvalues">valid values</a> below. + </dd> + <dt><code>android:layout_width</code></dt> + <dd><em>Dimension or keyword</em>. <strong>Required</strong>. The width for the group, as a +dimension value (or <a +href="more-resources.html#Dimension">dimension resource</a>) or a keyword ({@code "fill_parent"} +or {@code "wrap_content"}). See the <a href="#layoutvalues">valid values</a> below. + </dd> + </dl> + <p>More attributes are supported by the {@link android.view.ViewGroup} + base class, and many more are supported by each implementation of + {@link android.view.ViewGroup}. For a reference of all available attributes, + see the corresponding reference documentation for the {@link android.view.ViewGroup} class +(for example, the <a + href="{@docRoot}reference/android/widget/LinearLayout#lattrs">LinearLayout XML attributes</a>).</p> + </dd> + <dt id="view-element"><code><View></code></dt> + <dd>An individual UI component, generally referred to as a "widget". Different + kinds of {@link android.view.View} objects include {@link android.widget.TextView}, + {@link android.widget.Button}, and {@link android.widget.CheckBox}. + <p class="caps">attributes:</p> + <dl class="atn-list"> + <dt><code>android:id</code></dt> + <dd><em>Resource name</em>. A unique resource name for the element, which you can use to + obtain a reference to the {@link android.view.View} from your application. + The value takes the form: <code>"@+id/<em>name</em>"</code>. See more about the + <a href="#idvalue">value for {@code android:id}</a> below. + </dd> + <dt><code>android:layout_height</code></dt> + <dd><em>Dimension or keyword</em>. <strong>Required</strong>. The height for the element, as +a dimension value (or <a +href="more-resources.html#Dimension">dimension resource</a>) or a keyword ({@code "fill_parent"} +or {@code "wrap_content"}). See the <a href="#layoutvalues">valid values</a> below. + </dd> + <dt><code>android:layout_width</code></dt> + <dd><em>Dimension or keyword</em>. <strong>Required</strong>. The width for the element, as +a dimension value (or <a +href="more-resources.html#Dimension">dimension resource</a>) or a keyword ({@code "fill_parent"} +or {@code "wrap_content"}). See the <a href="#layoutvalues">valid values</a> below. + </dd> + </dl> + <p>More attributes are supported by the {@link android.view.View} + base class, and many more are supported by each implementation of + {@link android.view.View}. Read <a href="{@docRoot}guide/topics/ui/declaring-layout.html">Declaring + Layout</a> for more information. For a reference of all available attributes, + see the corresponding reference documentation (for example, the <a + href="{@docRoot}reference/android/widget/TextView.html#lattrs">TextView XML attributes</a>).</p> + </dd> + <dt id="requestfocus-element"><code><requestFocus></code></dt> + <dd>Any element representing a {@link android.view.View} object can include this empty element, + which gives it's parent initial focus on the screen. You can have only one of these + elements per file.</dd> + + </dl> + +<h4 id="idvalue">Value for <code>android:id</code></h4> + +<p>For the ID value, you should use this syntax form: <code>"@+id/<em>name</em>"</code>. The plus symbol, +{@code +}, indicates that this is a new resource ID and the aapt tool will create +a new resource number to the {@code R.java} class, if it doesn't already exist. For example:</p> +<pre> +<TextView android:id="@+id/nameTextbox"/> +</pre> +<p>You can then refer to it this way in Java:</p> +<pre> +findViewById(R.id.nameTextbox); +</pre> + +<h4 id="layoutvalues">Value for <code>android:layout_height</code> and +<code>android:layout_width</code>:</h4> + + <p>The height and width value can be expressed using any of the + <a href="more-resources.html#Dimension">dimension + units</a> supported by Android (px, dp, sp, pt, in, mm) or with the following keywords:</p> + <table><tr><th>Value</th><th>Description</th></tr> + <tr> + <td><code>match_parent</code></td> + <td>Sets the dimension to match that of the parent element. Added in API Level 8 to +deprecate <code>fill_parent</code>.</td> + </tr> + <tr> + <td><code>fill_parent</code></td> + <td>Sets the dimension to match that of the parent element.</td> + </tr><tr> + <td><code>wrap_content</code></td> + <td>Sets the dimension only to the size required to fit the content of this element.</td> + </tr> + </table> + +<h4>Custom View elements</h4> + +<p>You can create your own custom {@link android.view.View} and {@link android.view.ViewGroup} +elements and apply them to your layout the same as a standard layout +element. You can also specify the attributes supported in the XML element. To learn more, +read <a href="{@docRoot}guide/topics/ui/custom-components.html">Building Custom Components</a>. +</p> + +</dd> <!-- end elements and attributes --> + +<dt>example:</dt> +<dd>XML file saved at <code>res/layout/main_activity.xml</code>: +<pre> +<?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" > + <TextView android:id="@+id/text" + android:layout_width="wrap_content" + android:layout_height="wrap_content" + android:text="Hello, I am a TextView" /> + <Button android:id="@+id/button" + android:layout_width="wrap_content" + android:layout_height="wrap_content" + android:text="Hello, I am a Button" /> +</LinearLayout> +</pre> + <p>This application code will load the layout for an {@link android.app.Activity}, in the + {@link android.app.Activity#onCreate(Bundle) onCreate()} method:</dt> + <dd> +<pre> +public void onCreate(Bundle savedInstanceState) { + super.onCreate(savedInstanceState); + setContentView.(R.layout.main_activity); +} +</pre> +</dd> <!-- end example --> + + +<dt>see also:</dt> +<dd> +<ul> + <li><a href="{@docRoot}guide/topics/ui/declaring-layout.html">Declaring Layout</a></li> + <li>{@link android.view.View}</li> + <li>{@link android.view.ViewGroup}</li> +</ul> +</dd> + +</dl>
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