1 page.title=Maintaining Compatibility 2 3 @jd:body 4 5 <div id="tb-wrapper"> 6 <div id="tb"> 7 <h2>This lesson teaches you to</h2> 8 <ol> 9 <li><a href="#Theme">Define Alternative Styles</a></li> 10 <li><a href="#Layouts">Provide Alternative Layouts</a></li> 11 <li><a href="#SupportLib">Use the Support Library</a></li> 12 <li><a href="#CheckVersion">Check the System Version</a></li> 13 </ol> 14 <h2>You should also read</h2> 15 <ul> 16 <li><a href="http://www.google.com/design/spec">Material design specification</a></li> 17 <li><a href="{@docRoot}design/material/index.html">Material design on Android</a></li> 18 </ul> 19 </div> 20 </div> 21 22 23 <p>Some material design features like the material theme and custom activity transitions are 24 only available on Android 5.0 (API level 21) and above. However, you can design your apps to make 25 use of these features when running on devices that support material design and still be compatible 26 with devices running previous releases of Android.</p> 27 28 29 <h2 id="Theme">Define Alternative Styles</h2> 30 31 <p>You can configure your app to use the material theme on devices that support it and revert 32 to an older theme on devices running earlier versions of Android:</p> 33 34 <ol> 35 <li>Define a theme that inherits from an older theme (like Holo) in 36 <code>res/values/styles.xml</code>.</li> 37 <li>Define a theme with the same name that inherits from the material theme in 38 <code>res/values-v21/styles.xml</code>.</li> 39 <li>Set this theme as your app's theme in the manifest file.</li> 40 </ol> 41 42 <p class="note"><strong>Note:</strong> 43 If your app uses the material theme but does not provide an alternative theme in this manner, 44 your app will not run on versions of Android earlier than 5.0. 45 </p> 46 47 48 <h2 id="Layouts">Provide Alternative Layouts</h2> 49 50 <p>If the layouts that you design according to the material design guidelines do not use any of 51 the new XML attributes introduced in Android 5.0 (API level 21), they will work on previous 52 versions of Android. Otherwise, you can provide alternative layouts. You can also provide 53 alternative layouts to customize how your app looks on earlier versions of Android.</p> 54 55 <p>Create your layout files for Android 5.0 (API level 21) inside <code>res/layout-v21/</code> and 56 your alternative layout files for earlier versions of Android inside <code>res/layout/</code>. 57 For example, <code>res/layout/my_activity.xml</code> is an alternative layout for 58 <code>res/layout-v21/my_activity.xml</code>.</p> 59 60 <p>To avoid duplication of code, define your styles inside <code>res/values/</code>, modify the 61 styles in <code>res/values-v21/</code> for the new APIs, and use style inheritance, defining base 62 styles in <code>res/values/</code> and inheriting from those in <code>res/values-v21/</code>.</p> 63 64 65 <h2 id="SupportLib">Use the Support Library</h2> 66 67 <p>The <a href="{@docRoot}tools/support-library/features.html#v7">v7 Support Libraries</a> 68 r21 and above includes the following material design features:</p> 69 70 <ul> 71 <li><a href="{@docRoot}training/material/theme.html">Material design styles</a> for some system 72 widgets when you apply one of the <code>Theme.AppCompat</code> themes.</li> 73 <li><a href="{@docRoot}training/material/theme.html#ColorPalette">Color palette theme attributes</a> 74 in the <code>Theme.AppCompat</code> themes.</li> 75 <li>The {@link android.support.v7.widget.RecyclerView} widget to <a 76 href="{@docRoot}training/material/lists-cards.html#RecyclerView">display data 77 collections</a>.</li> 78 <li>The {@link android.support.v7.widget.CardView} widget to <a 79 href="{@docRoot}training/material/lists-cards.html#CardView">create cards</a>.</li> 80 <li>The {@link android.support.v7.graphics.Palette} class to <a 81 href="{@docRoot}training/material/drawables.html#ColorExtract">extract prominent colors from 82 images</a>.</li> 83 </ul> 84 85 <h3>System widgets</h3> 86 87 <p>The <code>Theme.AppCompat</code> themes provide material design styles for these widgets:</p> 88 89 <ul> 90 <li>{@link android.widget.EditText}</li> 91 <li>{@link android.widget.Spinner}</li> 92 <li>{@link android.widget.CheckBox}</li> 93 <li>{@link android.widget.RadioButton}</li> 94 <li>{@link android.support.v7.widget.SwitchCompat}</li> 95 <li>{@link android.widget.CheckedTextView}</li> 96 </ul> 97 98 <h3>Color Palette</h3> 99 100 <p>To obtain material design styles and customize the color palette with the Android v7 Support 101 Library, apply one of the <code>Theme.AppCompat</code> themes:</p> 102 103 <pre> 104 <!-- extend one of the Theme.AppCompat themes --> 105 <style name="Theme.MyTheme" parent="Theme.AppCompat.Light"> 106 <!-- customize the color palette --> 107 <item name="colorPrimary">@color/material_blue_500</item> 108 <item name="colorPrimaryDark">@color/material_blue_700</item> 109 <item name="colorAccent">@color/material_green_A200</item> 110 </style> 111 </pre> 112 113 <h3>Lists and Cards</h3> 114 115 <p>The {@link android.support.v7.widget.RecyclerView} and {@link 116 android.support.v7.widget.CardView} widgets are available in earlier versions of Android through 117 the Android v7 Support Library with these limitations:</p> 118 <ul> 119 <li>{@link android.support.v7.widget.CardView} falls back to a programmatic shadow implementation 120 using additional padding.</li> 121 <li>{@link android.support.v7.widget.CardView} does not clip its children views that intersect 122 with rounded corners.</li> 123 </ul> 124 125 126 <h3>Dependencies</h3> 127 128 <p>To use these features in versions of Android earlier than 5.0 (API level 21), include the 129 Android v7 Support Library in your project as a <a 130 href="{@docRoot}/sdk/installing/studio-build.html#dependencies">Gradle dependency</a>:</p> 131 132 <pre> 133 dependencies { 134 compile 'com.android.support:appcompat-v7:21.0.+' 135 compile 'com.android.support:cardview-v7:21.0.+' 136 compile 'com.android.support:recyclerview-v7:21.0.+' 137 } 138 </pre> 139 140 141 <h2 id="CheckVersion">Check the System Version</h2> 142 143 <p>The following features are available only in Android 5.0 (API level 21) and above:</p> 144 145 <ul> 146 <li>Activity transitions</li> 147 <li>Touch feedback</li> 148 <li>Reveal animations</li> 149 <li>Path-based animations</li> 150 <li>Vector drawables</li> 151 <li>Drawable tinting</li> 152 </ul> 153 154 <p>To preserve compatibility with earlier versions of Android, check the system {@link 155 android.os.Build.VERSION#SDK_INT version} at runtime before you invoke the APIs for any of these 156 features:</p> 157 158 <pre> 159 // Check if we're running on Android 5.0 or higher 160 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { 161 // Call some material design APIs here 162 } else { 163 // Implement this feature without material design 164 } 165 </pre> 166 167 <p class="note"><strong>Note:</strong> To specify which versions of Android your app supports, 168 use the <code>android:minSdkVersion</code> and <code>android:targetSdkVersion</code> 169 attributes in your manifest file. To use the material design features in Android 5.0, set 170 the <code>android:targetSdkVersion</code> attribute to <code>21</code>. For more information, see 171 the <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html"><uses-sdk> API 172 guide</a>.</p> 173
