page.title=Manifest Merging @jd:body
With Android Studio and Gradle-based builds, each app can
contain manifest files in multiple locations, such as the src/main/ folder for
the productFlavor, libraries, Android ARchive (AAR) bundles of Android Library
projects, and dependencies. During the build process, manifest merging combines the settings from
the various AndroidManifest.xml 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
build variant.
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.
Conflict markers and selectors can also define custom merge rules,
such as allowing an imported library to have a minSdkVersion higher than the
version defined in the other higher priority manifests.
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:
buildType manifest settings productFlavor manifest settings src/main/ directory of an app projectManifest merge conflicts are resolved at the XML node and attribute levels based on the following merge rules.
| High Priority Element | Low Priority Element | Manifest Merge Result |
|---|---|---|
| no attribute | no attribute | no attribute |
| attribute set to default | default attribute | |
| attribute set to non-default | low priority attribute | |
| attribute set to default | no attribute | default attribute |
| attribute set to non-default | high priority attribute | |
| attribute set to default | attribute set to default | default attribute |
| attribute set to default | attribute set to non-default | low priority attribute |
| attribute set to non-default | attribute set to default | high priority attribute |
| attribute set to non-default | attribute set to non-default | Merge if settings match, otherwise causes conflict error. |
Exceptions to the manifest merge rules:
uses-feature android:required; and
uses-library android:required elements default to true and use
an OR merge so that any required feature or library is included in the generated APK. <uses-sdk>
elements, minSdkVersion and
targetSdkVersion, default to a value of 1. When
merge conflicts occur, the value in the higher priority manifest version is used.minSdkVersion value higher than the app's
src/main/ manifest manifest generates an error unless
the overrideLibrary conflict marker is used.
Note: If not explicitly declared, the targetSdkVersion
defaults to the minSdkVersion value. When no element is
present in any manifest or the build.gradle file, the
minSdkVersion defaults to 1.
targetSdkVersion value lower than the app's
src/main/ manifest, the manifest merge
process explicitly grants permissions and ensures that the imported library functions properly. manifest element only merges with child manifest elements. intent-filter element is never changed and is always added to the common
parent node in the merged manifest. Important: After the manifests are merged, the build process
overrides the final manifest settings with any settings that are also in the
build.gradle file. For more details, see
Configuring Gradle Builds.
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 minSdkVersion value than the higher priority
manifest, or to merge manifests with the same activity but different android:theme
values.
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:
mergereplacestrictmerge-onlyremoveremove-AllBy default, the manifest merge process applies the merge conflict marker to
the node level. All declared manifest attributes default to a strict
merging policy.
To set a merge conflict marker, first declare the namespace in the
AndroidManifest.xml file. Then, enter the merge conflict marker in the manifest to
specify a custom merge conflict action. This example inserts the replace marker to
set a replace action to resolve conflicts between the android:icon and
android:label manifest elements.
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.tests.flavorlib.app"
xmlns:tools="http://schemas.android.com/tools">
<application
android:icon="@drawable/icon"
android:label="@string/app_name"
tools:replace="icon, label">
...
Conflict markers use tools:node and tools:attr attributes to
restrict merge actions at the XML node or attribute level.
The tools:attr markers use only the restrict, remove, and
replace merge actions. Multiple tools:attr marker values can be applied
to a specific element. For example, use tools:replace="icon, label, theme" to replace
lower priority icon, label, and theme attributes.
The overrideLibrary conflict marker applies to the <uses-sdk>
manifest declaration and is used to import a library even though the library's
<uses-sdk> values, such as minSdkVersion
are set to different values than those in the other higher priority manifests.
Without this marker, library manifest merge conflicts from the
<uses-sdk> values cause the merge process to fail.
This example applies the overrideLibrary conflict marker to resolve the merge
conflict between minSdkVersion values in the src/main/ manifest and an
imported library manifest.
src/main/ manifest:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.example.app"
xmlns:tools="http://schemas.android.com/tools">
...
<uses-sdk android:targetSdkVersion="22" android:minSdkVersion="2"
tools:overrideLibrary="com.example.lib1, com.example.lib2"/>
...
Library manifest:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.lib1">
...
<uses-sdk android:minSdkVersion="4" />
...
</manifest>
Note: The default merge process does not allow importing a library
with a higher minSdkVersion than the app's src/main/ manifest unless
the overrideLibrary conflict marker is used.
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.
This example uses the tools:node marker to remove the permisionOne
attribute, while the tools:selector selector specifies the specific library as
com.example.lib1. The permisionOne permission is filtered from only the
lib1 library manifests.
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.example.app"
xmlns:tools="http://schemas.android.com/tools">
...
<permission
android:name="permissionOne"
tools:node="remove"
tools:selector="com.example.lib1">
...
Manifest merging can also be configured to use manifest placeholders to inject
property values from the build.gradle file into the manifest attributes.
Manifest placeholders use the syntax ${name} for attribute values, where
name is the injected build.gradle property. The build.gradle
file uses the manifestPlaceholders property to define the placeholder values.
Note: 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.
This example shows the manifest placeholder ${applicationId} used to inject the
build.gradle applicationId property value in to android:name
attribute value.
Note: Android Studio provides a default
${applicationId} placeholder for the build.gradle
applicationId value that is not shown in the build file.
When building an AAR (Android ARchive) package for library modules, do not provide an
automatic @{applicationId} placeholder in the
manifest merge settings.
Instead, use a different placeholder, such as @{libApplicationId} and
provide a value for it if you want to include application Ids in the archive library.
Manifest entry:
<activity
android:name=".Main">
<intent-filter>
<action android:name="${applicationId}.foo">
</action>
</intent-filter>
</activity>
Gradle build file:
android {
compileSdkVersion 22
buildToolsVersion "22.0.1"
productFlavors {
flavor1 {
applicationId = "com.mycompany.myapplication.productFlavor1"
}
}
Merged manifest value:
<action android:name="com.mycompany.myapplication.productFlavor1.foo">
The manifest placeholder syntax and build file manifestPlaceholders
property can be used to inject other manifest values. For properties other than the
applicationId, the manifestPlaceholders property is explicitly declared
in the build.gradle file. This example shows the manifest placeholder for injecting
activityLabel values.
Gradle build file:
android {
defaultConfig {
manifestPlaceholders = [ activityLabel:"defaultName"]
}
productFlavors {
free {
}
pro {
manifestPlaceholders = [ activityLabel:"proName" ]
}
}
Placeholder in the manifest file:
<activity android:name=".MainActivity" android:label="${activityLabel}" >
Note: The placeholder value supports partial value injection,
for example android:authority="com.acme.${localApplicationId}.foo".
When using the GroupableProductFlavor 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.
For example, if a build variant references the product flavors x86,
mdpi, 21, and paid from the respective product flavor
groups ABI, Density, API, and Prod, listed
in this order in the build.gradle 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.
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.
| Product Flavor Group | Product Flavor |
|---|---|
| ABI | x86 |
| density | mdpi |
| API | 22 |
| prod | paid |
Manifest merge order:
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 targetSdkVersion of 16 imports a library with a
targetSdkVersion of 2, Android Studio adds the WRITE_EXTERNAL_STORAGE
permission to ensure permission compatibility across the SDK versions.
Note: More recent Android releases replace implicit permissions with permission declarations.
This table lists the importing library versions and the declared permissions.| Importing this library version | Declares this permission in the manifest |
|---|---|
targetSdkVersion < 2 |
WRITE_EXTERNAL_STORAGE |
targetSdkVersion < 4 |
WRITE_EXTERNAL_STORAGE, READ_PHONE_STATE |
Declared WRITE_EXTERNAL_STORAGE |
READ_EXTERNAL_STORAGE |
targetSdkVersion < 16 and using the READ_CONTACTS
permission |
READ_CALL_LOG |
targetSdkVersion < 16 and using the WRITE_CONTACTS
permission |
WRITE_CALL_LOG |
During the build process, the manifest merge process stores a record of each merge transaction
in the manifest-merger-<productFlavor>-report.txt file in the module
build/outputs/logs folder. A different log file is generated for each of the
module's build variants.
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
android:screenOrientation merge conflict between the following manifests causes
a build error.
Higher priority manifest declaration:
<activity android:name="com.foo.bar.ActivityOne" android:screenOrientation="portrait" android:theme="@theme1"/>
Lower priority manifest declaration:
<activity android:name="com.foo.bar.ActivityOne" android:screenOrientation="landscape"/>
Error log:
/project/app/src/main/AndroidManifest.xml:3:9 Error: Attribute activity@screenOrientation value=(portrait) from AndroidManifest.xml:3:9 is also present at flavorlib:lib1:unspecified:3:18 value=(landscape) Suggestion: add 'tools:replace="icon"' toelement at AndroidManifest.xml:1:5 to override