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diff --git a/docs/html/training/tv/optimizing-navigation-tv.jd b/docs/html/training/tv/optimizing-navigation-tv.jd new file mode 100644 index 0000000..bb78258 --- /dev/null +++ b/docs/html/training/tv/optimizing-navigation-tv.jd @@ -0,0 +1,206 @@ +page.title=Optimizing Navigation for TV +parent.title=Designing for TV +parent.link=index.html + +trainingnavtop=true +previous.title=Optimizing Layouts for TV +previous.link=optimizing-layouts-tv.html +next.title=Handling Features Not Supported on TV +next.link=unsupported-features-tv.html + +@jd:body + +<div id="tb-wrapper"> +<div id="tb"> + +<h2>This lesson teaches you to</h2> +<ol> + <li><a href="#HandleDpadNavigation">Handle D-pad Navigation</a></li> + <li><a href="#HandleFocusSelection">Provide Clear Visual Indication for Focus and Selection</a></li> + <li><a href="#DesignForEasyNavigation">Design for Easy Navigation</a></li> +</ol> + +<h2>You should also read</h2> +<ul> + <li><a href="{@docRoot}training/design-navigation/index.html">Designing Effective Navigation</a></li> +</ul> + +</div> +</div> + +<p> +An important aspect of the user experience when operating a TV is the direct human interface: a remote control. +As you optimize your Android application for TVs, you should pay special attention to how the user actually navigates +around your application when using a remote control instead of a touchscreen. +</p> +<p> +This lesson shows you how to optimize navigation for TV by: +</p> + +<ul> + <li>Ensuring all layout controls are D-pad navigable.</li> + <li>Providing highly obvious feedback for UI navigation.</li> + <li>Placing layout controls for easy access.</li> +</ul> + +<h2 id="HandleDpadNavigation">Handle D-pad Navigation</h2> + +<p> +On a TV, users navigate with controls on a TV remote, using either a D-pad or arrow keys. +This limits movement to up, down, left, and right. +To build a great TV-optimized app, you must provide a navigation scheme in which the user can +quickly learn how to navigate your app using the remote. +</p> + +<p> +When you design navigation for D-pad, follow these guidelines: +</p> + +<ul> + <li>Ensure that the D-pad can navigate to all the visible controls on the screen.</li> + <li>For scrolling lists with focus, D-pad up/down keys scroll the list and Enter key selects an item in the list. Ensure that users can + select an element in the list and that the list still scrolls when an element is selected.</li> + <li>Ensure that movement between controls is straightforward and predictable.</li> +</ul> + +<p> +Android usually handles navigation order between layout elements automatically, so you don't need to do anything extra. If the screen layout +makes navigation difficult, or if you want users to move through the layout in a specific way, you can set up explicit navigation for your +controls. +For example, for an {@code android.widget.EditText}, to define the next control to receive focus, use: +<pre> +<EditText android:id="@+id/LastNameField" android:nextFocusDown="@+id/FirstNameField"\> +</pre> +The following table lists all of the available navigation attributes: +</p> + +<table> +<tr> +<th>Attribute</th> +<th>Function</th> +</tr> +<tr> +<td>{@link android.R.attr#nextFocusDown}</td> +<td>Defines the next view to receive focus when the user navigates down.</td> +</tr> +<tr> +<td>{@link android.R.attr#nextFocusLeft}</td> +<td>Defines the next view to receive focus when the user navigates left.</td> +</tr> +<tr> +<td>{@link android.R.attr#nextFocusRight}</td> +<td>Defines the next view to receive focus when the user navigates right.</td> +</tr> +<tr> +<td>{@link android.R.attr#nextFocusUp}</td> +<td>Defines the next view to receive focus when the user navigates up.</td> +</tr> +</table> + +<p> +To use one of these explicit navigation attributes, set the value to the ID (android:id value) of another widget in the layout. You should set +up the navigation order as a loop, so that the last control directs focus back to the first one. +</p> + +<p> +Note: You should only use these attributes to modify the navigation order if the default order that the system applies does not work well. +</p> + +<h2 id="HandleFocusSelection">Provide Clear Visual Indication for Focus and Selection</h2> + +<p> +Use appropriate color highlights for all navigable and selectable elements in the UI. This makes it easy for users to know whether the control +is currently focused or selected when they navigate with a D-pad. Also, use uniform highlight scheme across your application. +</p> + +<p> +Android provides <a href="{@docRoot}guide/topics/resources/drawable-resource.html#StateList">Drawable State List Resources</a> to implement highlights +for selected and focused controls. For example: +</p> + +res/drawable/button.xml: +<pre> +<?xml version="1.0" encoding="utf-8"?> +<selector xmlns:android="http://schemas.android.com/apk/res/android"> + <item android:state_pressed="true" + android:drawable="@drawable/button_pressed" /> <!-- pressed --> + <item android:state_focused="true" + android:drawable="@drawable/button_focused" /> <!-- focused --> + <item android:state_hovered="true" + android:drawable="@drawable/button_focused" /> <!-- hovered --> + <item android:drawable="@drawable/button_normal" /> <!-- default --> +</selector> +</pre> + +<p> +This layout XML applies the above state list drawable to a {@link android.widget.Button}: +</p> +<pre> +<Button + android:layout_height="wrap_content" + android:layout_width="wrap_content" + android:background="@drawable/button" /> +</pre> + +<p> +Provide sufficient padding within the focusable and selectable controls so that the highlights around them are clearly visible. +</p> + +<h2 id="DesignForEasyNavigation">Design for Easy Navigation</h2> + +<p> +Users should be able to navigate to any UI control with a couple of D-pad clicks. Navigation should be easy and intuitive to +understand. For any non-intuitive actions, provide users with written help, using a dialog triggered by a help button or action bar icon. +</p> + +<p> +Predict the next screen that the user will want to navigate to and provide one click navigation to it. If the current screen UI is very sparse, +consider making it a multi pane screen. Use fragments for making multi-pane screens. For example, consider the multi-pane UI below with continent names +on the left and list of cool places in each continent on the right. +</p> + +<img src="{@docRoot}images/training/cool-places.png" alt="" /> + +<p> +The above UI consists of three Fragments - <code>left_side_action_controls</code>, <code>continents</code> and +<code>places</code> - as shown in its layout +xml file below. Such multi-pane UIs make D-pad navigation easier and make good use of the horizontal screen space for +TVs. +</p> +res/layout/cool_places.xml +<pre> +<LinearLayout + android:layout_width="match_parent" + android:layout_height="match_parent" + android:orientation="horizontal" + > + <fragment + android:id="@+id/left_side_action_controls" + android:layout_width="0px" + android:layout_height="match_parent" + android:layout_marginLeft="10dip" + android:layout_weight="0.2"/> + <fragment + android:id="@+id/continents" + android:layout_width="0px" + android:layout_height="match_parent" + android:layout_marginLeft="10dip" + android:layout_weight="0.2"/> + + <fragment + android:id="@+id/places" + android:layout_width="0px" + android:layout_height="match_parent" + android:layout_marginLeft="10dip" + android:layout_weight="0.6"/> + +</LinearLayout> +</pre> + +<p> +Also, notice in the UI layout above action controls are on the left hand side of a vertically scrolling list to make +them easily accessible using D-pad. +In general, for layouts with horizontally scrolling components, place action controls on left or right hand side and +vice versa for vertically scrolling components. +</p> + |