android_frameworks_base/docs/html/tools/building/manifest-merge.jd

page.title=Manifest Merging
@jd:body

<div id="qv-wrapper">
<div id="qv">

  <h2>In this document</h2>
  <ol>
    <li><a href="#merge-rules">Merge Conflict Rules</a></li>
    <li><a href="#markers-selectors">Merge Conflict Markers and Selectors</a></li>
    <li><a href="#inject-values">Injecting Build Values into a Manifest</a></li>
    <li><a href="#merge-prodflavorsGroups">Manifest Merging Across Product Flavor Groups</a></li>
    <li><a href="#implicit-permissions">Implicit Permissions</a></li>
    <li><a href="#merge-errors">Handling Manifest Merge Build Errors</a></li>
  </ol>

  <h2>See also</h2>
  <ol>
    <li><a href="{@docRoot}sdk/installing/studio-build.html">Build System Overview</a></li>
    <li><a href="{@docRoot}tools/building/configuring-gradle.html">Configuring Gradle Builds</a> </li>
  </ol>

</div>
</div>


<p>With Android Studio and <a href="http://www.gradle.org">Gradle</a>-based builds, each app can
contain manifest files in multiple locations, such as the <code>src/main/</code> folder for
the <code>productFlavor</code>, libraries, Android ARchive (AAR) bundles of Android Library
projects, and dependencies. During the build process, manifest merging combines the settings from
the various <code>AndroidManifest.xml</code> files included in your app into a single, generated APK
manifest file for app packaging and distribution. Manifest settings are merged based on the manifest
priority, determined by the manifest's file location. Building your app merges the
manifest elements, attributes, and sub-elements from these manifests for the specified
<a href="{@docRoot}tools/building/configuring-gradle.html#workBuildVariants">build variant</a>.</p>


<h2 id="merge-rules">Merge Conflict Rules</h2>
<p>Merge conflicts occur when merged manifests contain the same manifest element but with a
different attribute value that does not resolve based on the default merge conflict rules.
<a href="#markers-selectors">Conflict markers and selectors</a> can also define custom merge rules,
such as allowing an imported library to have a <code>minSdkVersion</code> higher than the
version defined in the other higher priority manifests.  </p>

<p>The manifest merge priority determines which manifest settings are retained in merge conflicts,
with the settings in higher priority manifest overwriting those in lower priority manifests.
The following list details which manifest settings are are the highest priority during the merge
process:</p>

<ul>
 <li>Highest priority: <code>buildType</code> manifest settings </li>
 <li>Higher priority: <code>productFlavor</code> manifest settings </li>
 <li>Medium priority: Manifests in the <code>src/main/</code> directory of an app project</li>
 <li>Low priority: Dependency and library manifest settings </li>
</ul>

<p>Manifest merge conflicts are resolved at the XML node and
attribute levels based on the following merge rules. </p>

<table>
    <tr>
        <th scope="col">High Priority Element</th>
        <th scope="col">Low Priority Element</th>
        <th scope="col">Manifest Merge Result</th>
    </tr>
    <tr>
        <td rowspan="3">no attribute</td>
        <td>no attribute</td>
        <td>no attribute</td>
    </tr>
    <tr>

        <td>attribute set to default</td>
        <td>default attribute</td>
    </tr>
    <tr>

        <td>attribute set to non-default </td>
        <td>low priority attribute</td>
    </tr>
    <tr>
        <td>attribute set to default</td>
        <td rowspan="2">no attribute</td>
        <td>default attribute</td>
    </tr>
    <tr>
        <td>attribute set to non-default </td>

        <td>high priority attribute</td>
    </tr>
    <tr>
        <td>attribute set to default</td>
        <td>attribute set to default</td>
        <td>default attribute</td>
    </tr>
    <tr>
        <td>attribute set to default</td>
        <td>attribute set to non-default </td>
        <td>low priority attribute</td>
    </tr>
    <tr>
        <td>attribute set to non-default</td>
        <td>attribute set to default</td>
        <td>high priority attribute</td>
    </tr>
    <tr>
        <td>attribute set to non-default</td>
        <td>attribute set to non-default </td>
        <td>Merge if settings match, otherwise causes conflict error.</td>
    </tr>
   </table>



<p>Exceptions to the manifest merge rules: </p>

<ul>
 <li>The <code>uses-feature android:required;</code> and
 <code>uses-library android:required</code> elements default to <code>true</code> and use
 an <em>OR</em> merge so that any required feature or library is included in the generated APK. </li>

 <li>If not declared, the
 <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html"><code>&lt;uses-sdk&gt;</code></a>
 elements, <code>minSdkVersion</code> and
 <code>targetSdkVersion</code>, default to a value of 1. When
 merge conflicts occur, the value in the higher priority manifest version is used.</li>

 <li>Importing a library with a <code>minSdkVersion</code> value higher than the app's
 <code>src/main/</code> manifest manifest generates an error unless
 the <code>overrideLibrary</code> conflict marker is used.

 <p class="note"><strong>Note:</strong> If not explicitly declared, the <code>targetSdkVersion</code>
 defaults to the <code>minSdkVersion</code> value. When no <code><uses-sdk></code> element is
 present in any manifest or the <code>build.gradle</code> file, the
 <code>minSdkVersion</code> defaults to 1.</p> </li>

 <li>When importing a library with a <code>targetSdkVersion</code> value lower than the app's
 <code>src/main/</code> manifest, the manifest merge
 process explicitly grants permissions and ensures that the imported library functions properly. </li>

 <li>The <code>manifest</code> element only merges with child manifest elements. </li>

 <li>The <code>intent-filter</code> element is never changed and is always added to the common
 parent node in the merged manifest. </li>
</ul>

<p class="caution"><strong>Important:</strong> After the manifests are merged, the build process
overrides the final manifest settings with any settings that are also in the
<code>build.gradle</code> file. For more details, see
<a href="{@docRoot}tools/building/configuring-gradle.html">Configuring Gradle Builds</a>. </p>



<h2 id="markers-selectors">Merge Conflict Markers and Selectors</h2>
<p>Manifest markers and selectors override the default merge rules through
specific conflict resolutions. For example, use a conflict marker to
merge a library manifest with a higher <code>minSdkVersion</code> value than the higher priority
manifest, or to merge manifests with the same activity but different <code>android:theme</code>
values. </p>

<h3 id="conflict-markers">Merge Conflict Markers</h3>
<p>A merge conflict marker is a special attribute in the Android tools namespace that defines a
specific merge conflict resolution. Create a conflict marker to avoid a merge conflict error for
conflicts not resolved by the default merge rules. Supported merge conflict markers include:</p>

<dl>
  <dt><code>merge</code></dt>
    <dd>Merges attributes when there are no conflicts with the merge rules. The default merge
    action.</dd>
  <dt><code>replace</code></dt>
    <dd>Replaces attributes in the lower priority manifest with those from the higher priority
    manifest.</dd>
  <dt><code>strict</code></dt>
    <dd>Sets the merge policy level so that merged elements with same attributes, but different
     values generate a build failure, unless resolved through the conflict rules.</dd>
  <dt><code>merge-only</code></dt>
    <dd>Allows merge actions for only lower priority attributes.</dd>
  <dt><code>remove</code></dt>
    <dd>Removes the specified lower priority element from the merged manifest.</dd>
  <dt><code>remove-All</code></dt>
    <dd>Removes all lower priority elements of the same node type from the merged manifest.</dd>
</dl>


<p>By default, the manifest merge process applies the <code>merge</code> conflict marker to
the node level. All declared manifest attributes default to a <code>strict</code>
merging policy. </p>

<p>To set a merge conflict marker, first declare the namespace in the
<code>AndroidManifest.xml</code> file. Then, enter the merge conflict marker in the manifest to
specify a custom merge conflict action. This example inserts the <code>replace</code> marker to
set a replace action to resolve conflicts between the <code>android:icon</code> and
<code>android:label</code> manifest elements. </p>

<pre>

&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.android.tests.flavorlib.app"
   xmlns:tools="http://schemas.android.com/tools"&gt;

   &lt;application
       android:icon="&#64;drawable/icon"
       android:label="&#64;string/app_name"
       tools:replace="icon, label"&gt;
       ...

</manifest>

</pre>


<h4>Marker attributes</h4>
<p>Conflict markers use <code>tools:node</code> and <code>tools:attr</code> attributes to
restrict merge actions at the XML node or attribute level. </p>

<p>The <code>tools:attr</code> markers use only the <code>restrict</code>, <code>remove</code>, and
<code>replace</code> merge actions. Multiple <code>tools:attr</code> marker values can be applied
to a specific element. For example, use <code>tools:replace="icon, label, theme"</code> to replace
lower priority <code>icon</code>, <code>label</code>, and <code>theme</code> attributes. </p>


<h4>Merge conflict marker for imported libraries</h4>
<p>The <code>overrideLibrary</code> conflict marker applies to the <code>&lt;uses-sdk&gt;</code>
manifest declaration and is used to import a library even though the library's
<code>&lt;uses-sdk&gt;</code> values, such as <code>minSdkVersion</code>
are set to different values than those in the other higher priority manifests. </p>

<p>Without this marker, library manifest merge conflicts from the
<code>&lt;uses-sdk&gt;</code> values cause the merge process to fail.</p>

<p>This example applies the <code>overrideLibrary</code> conflict marker to resolve the merge
conflict between <code>minSdkVersion</code> values in the <code>src/main/</code> manifest and an
imported library manifest.


<p><code>src/main/</code> manifest: </p>
<pre>
&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.android.example.app"
   xmlns:tools="http://schemas.android.com/tools"&gt;
   ...
   &lt;uses-sdk android:targetSdkVersion="22" android:minSdkVersion="2"
             tools:overrideLibrary="com.example.lib1, com.example.lib2"/&gt;
   ...
</pre>

<p>Library manifest: </p>

<pre>
&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
   	 package="com.example.lib1"&gt;
     ...
   	 &lt;uses-sdk android:minSdkVersion="4" /&gt;
     ...
    &lt;/manifest&gt;
</pre>

<p class="note"><strong>Note:</strong> The default merge process does not allow importing a library
with a higher <code>minSdkVersion</code> than the app's <code>src/main/</code> manifest unless
the <code>overrideLibrary</code> conflict marker is used. </p>



<h3 id="marker-selectors">Marker Selectors</h3>
<p>Marker selectors limit a merge action to a specific lower priority manifest. For example, a
marker selector can be used to remove a permission from only one library, while allowing the
same permission from other libraries.</p>

<p>This example uses the <code>tools:node</code> marker to remove the <code>permisionOne</code>
attribute, while the <code>tools:selector</code> selector specifies the specific library as
<em>com.example.lib1</em>. The <code>permisionOne</code> permission is filtered from only the
<code>lib1</code> library manifests. </p>

<pre>
&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.android.example.app"
   xmlns:tools="http://schemas.android.com/tools"&gt;
   ...
   &lt;permission
         android:name="permissionOne"
         tools:node="remove"
         tools:selector="com.example.lib1"&gt;
   ...
</pre>



<h2 id="inject-values">Injecting Build Values into a Manifest</h2>
<p>Manifest merging can also be configured to use manifest placeholders to inject
property values from the <code>build.gradle</code> file into the manifest attributes. </p>

<p>Manifest placeholders use the syntax <code>&#36;{name}</code> for attribute values, where
<code>name</code> is the injected <code>build.gradle</code> property. The <code>build.gradle</code>
file uses the <code>manifestPlaceholders</code> property to define the placeholder values. </p>

<p class="note"><strong>Note:</strong> Unresolved placeholder names in apps cause build failures.
Unresolved placeholder names in libraries generate warnings and need to be resolved when importing
the library into an app.</p>

<p>This example shows the manifest placeholder <code>&#36;{applicationId}</code> used to inject the
<code>build.gradle</code> <code>applicationId</code> property value in to <code>android:name</code>
attribute value.  </p>

<p class="note"><strong>Note:</strong> Android Studio provides a default
<code>&#36;{applicationId}</code> placeholder for the <code>build.gradle</code>
<code>applicationId</code> value that is not shown in the build file.</p>


<p>Manifest entry:</p>

<pre>

&lt;activity
android:name=".Main"&gt;
     &lt;intent-filter&gt;
     &lt;action android:name="&#36;{applicationId}.foo"&gt;
         &lt;/action&gt;
&lt;/intent-filter&gt;
&lt;/activity&gt;

</pre>


<p>Gradle build file:</p>

<pre>
android {
   compileSdkVersion 22
   buildToolsVersion "22.0.1"

   productFlavors {
       flavor1 {
           applicationId = "com.mycompany.myapplication.productFlavor1"
       }
}

</pre>

<p>Merged manifest value: </p>

<pre>
&lt;action android:name="com.mycompany.myapplication.productFlavor1.foo"&gt;
</pre>


<p>The manifest placeholder syntax and build file <code>manifestPlaceholders</code>
property can be used to inject other manifest values. For properties other than the
<code>applicationId</code>, the <code>manifestPlaceholders</code> property is explicitly declared
in the <code>build.gradle</code> file. This example shows the manifest placeholder for injecting
<code>activityLabel</code> values.</p>

<p>Gradle build file: </p>

<pre>
android {
    defaultConfig {
        manifestPlaceholders = [ activityLabel:"defaultName"]
    }
    productFlavors {
        free {
        }
        pro {
            manifestPlaceholders = [ activityLabel:"proName" ]
        }
    }

</pre>

<p>Placeholder in the manifest file: </p>

<pre>
&lt;activity android:name=".MainActivity" android:label="&#36;{activityLabel}" &gt;
</pre>

<p class="note"><strong>Note:</strong> The placeholder value supports partial value injection,
for example <code>android:authority="com.acme.&#36;{localApplicationId}.foo"</code>. </p>



<h2 id="merge-prodflavorsGroups">Manifest Merging Across Product Flavor Groups</h2>

<p>When using the <code>GroupableProductFlavor</code> property, the manifest merge
priority of any manifests in the product flavor groups follows the order in which the
product flavor groups are listed in the build file. The manifest merge process creates a single
merged manifest for the product flavor groups based on the configured build variant. </p>

<p>For example, if a build variant references the product flavors <code>x86</code>,
<code>mdpi</code>, <code>21</code>, and <code>paid</code> from the respective product flavor
groups <code>ABI</code>, <code>Density</code>, <code>API</code>, and <code>Prod</code>, listed
in this order in the <code>build.gradle</code> file, then the manifest merge process merges the
manifests in this priority order, which follows how the product flavors are listed in the build
file.</p>

<p>To illustrate this example, the following table shows how the product flavors are listed for
each product flavor group. This combination of product flavors and groups defines the
build variant. </p>
<table>
    <tr>
        <th scope="col">Product Flavor Group</th>
        <th scope="col">Product Flavor</th>
    <tr>
        <td>ABI</td>
        <td>x86</td>
    </tr>
    <tr>
       <td>density</td>
        <td>mdpi</td>
    </tr>
    <tr>
        <td>API</td>
        <td>22</td>
    </tr>
    <tr>
        <td>prod</td>
        <td>paid</td>
    </tr>
</table>

<p>Manifest merge order:</p>

 <ul>
  <li>prod-paid AndroidManifest.xml (lowest priority) merges into API-22 AndroidManifest.xml</li>
  <li>API-22 AndroidManifest.xml merges into density-mpi AndroidManifest.xml</li>
  <li>density-mpi AndroidManifest.xml merges into ABI-x86 AndroidManifest.xml (highest priority)</li>
 </ul>


<h2 id="implicit-permissions">Implicit Permissions</h2>
<p>Importing a library that targets an Android runtime with implicitly
granted permissions may automatically add the permissions to the resulting merged manifest.
For example, if an application with a <code>targetSdkVersion</code> of 16 imports a library with a
<code>targetSdkVersion</code> of 2, Android Studio adds the <code>WRITE_EXTERNAL_STORAGE</code>
permission to ensure permission compatibility across the SDK versions.

<p class="note"><strong>Note:</strong> More recent Android releases replace implicit
permissions with permission declarations.</p>


This table lists the importing library versions and the declared permissions.
</p>

  <table>
    <tr>
      <th>Importing this library version</th>
      <th>Declares this permission in the manifest </th>
    </tr>
    <tr>
      <td><code>targetSdkVersion</code> &lt; 2 </td>
      <td><code>WRITE_EXTERNAL_STORAGE</code> </td>
    </tr>
    <tr>
      <td><code>targetSdkVersion</code> &lt; 4 </td>
      <td><code>WRITE_EXTERNAL_STORAGE</code>, <code>READ_PHONE_STATE</code> </td>
    </tr>
    <tr>
      <td>Declared <code>WRITE_EXTERNAL_STORAGE</code></td>
      <td><code>READ_EXTERNAL_STORAGE</code></td>
    </tr>
    <tr>
      <td><code>targetSdkVersion</code> &lt; 16 and using the <code>READ_CONTACTS</code>
      permission</td>
      <td><code>READ_CALL_LOG</code></td>
    </tr>
    <tr>
      <td><code>targetSdkVersion</code> &lt; 16 and using the <code>WRITE_CONTACTS</code>
      permission</td>
      <td><code>WRITE_CALL_LOG</code></td>
    </tr>
  </table>



<h2 id="merge-errors">Handling Manifest Merge Build Errors</h2>
<p>During the build process, the manifest merge process stores a record of each merge transaction
in the <code>manifest-merger-&lt;productFlavor&gt;-report.txt</code> file in the module
<code>build/outputs/logs</code> folder. A different log file is generated for each of the
module's build variants. </p>

<p>When a manifest merge build error occurs, the merge process records the error message
describing the merge conflict in the log file. For example, the
<code>android:screenOrientation</code> merge conflict between the following manifests causes
a build error. </p>

<p>Higher priority manifest declaration: </p>

<pre>
&lt;activity
   android:name="com.foo.bar.ActivityOne"
   android:screenOrientation="portrait"
   android:theme="&#64;theme1"/&gt;
</pre>

<p>Lower priority manifest declaration: </p>

<pre>
&lt;activity
   android:name="com.foo.bar.ActivityOne"
   android:screenOrientation="landscape"/&gt;
</pre>

<p>Error log:</p>

<pre>
/project/app/src/main/AndroidManifest.xml:3:9 Error:
 Attribute activity&#64;screenOrientation value=(portrait) from AndroidManifest.xml:3:9
 is also present at flavorlib:lib1:unspecified:3:18 value=(landscape)
 Suggestion: add 'tools:replace="icon"' to <activity> element at AndroidManifest.xml:1:5 to override
</pre>