How to use the new manifest merger (of Android Studio and Gradle)?

Question

Background

In the past, when Eclipse&ADT were the official tools to develop for Android, you could simply use "manifestmerger.enabled=true" inside the "project.properties" of the app's project, and you got it merging all of the libraries' manifests automatically (and I've posted about it here).

This worked, sometimes. It had a lot of weird issues, and I always preferred to just avoid using it, and put what is needed into the main manifest file manually.

The problem

Somewhere on 2014, Google announced that the new Android-Studio (0.1 I think), together with Gradle, will allow you to choose exactly how to perform merging of libraries' components.

However, the new instructions (link here) are very complex and I really (really) tried to understand how to use them, and also didn't find samples of how to use them.

It's not that I didn't understand anything, but I'm not sure if I understood well.

What I've found

On the bright side, I've found out that merging is done completely automatically, so if you have a BroadcastReceiver on the library's manifest (and as a class, of course), it will be added to the app's project that uses it.

The question

I can't simply ask everything to be explained. I think it will be enough to ask those questions:

1. How can I choose which app components (permissions, activities,...) to be ignored from being auto-merged?

2. How can I point override app components (of the library) attributes (on the app's project) ? for example the theme of the activities?

3. Is there a way to completely disable the auto-merger for the manifest files?

4. What happens with manifests of dependencies that are inside repositories? Are they merged too?

5. Are there any tutorials/samples/videos regarding this new (well new for me) feature?

6. Are there any things I should be aware of when using the auto-merger?

I hope those questions are representative enough, informative enough, yet not too hard to answer for people who know.

1. Disabling elements

You can always explicitly disable permissions and features in your app's manifest and override any library values. And i found that you can disable elements from library.

Example

Consider the following code from the above link:

<activity-alias android:name="foo.bar.alias">
    <meta-data 
        android:name="zoo"
        tools:node="remove" />
</activity-alias>

By having this code inside your manifest you ensure that the merger finds any <activity-alias> elements with android:name="foo.bar.alias" attribute and removes a <meta-data> element if it has the android:name="zoo" attribute. It removes just the "zoo" meta data. Not the activity alias. If you specify this in your main manifest it will be effective on anything that has been merged so far (elements from libraries).

Example #2

Since you requested an example with activities, this is what I've come up with:

<activity android:name="com.example.ui.MyActivity" tools:node="remove" />

This line will make the merger remove any activities with android:name="com.example.ui.MyActivity" attribute that have been merged so far. So if you specify this in your main manifest it will effectively remove any com.example.ui.MyActivity entries that might have been merged from libraries.

2. Overriding attributes from library

The order in which the values are merged are described here. Basically, it goes like this: libraries, then main manifest, then flavors and build types manifests if you use those.

What are build types?

The default are "debug" and "release". You can define your own and override settings like signing or proguard. For your purposes you could say it's the equivalent of run configurations.

It works like this: you put your default and shared values inside the main manifest. Then in flavor manifests you override the values you need. Google "gradle flavors" for more info.

The following example is taken from a previous version of manifest merger documentation.

Override an attribute coming from a library

Using tools:replace="x, y, z" will override x,y,z attributes from the imported library’s activity XML declarations.

Higher Priority declaration

<activity
    android:name="com.foo.bar.ActivityOne"
    android:screenOrientation="portrait"
    android:theme="@theme1"
    tools:replace="theme"/>

with a lower priority declaration :

<activity
    android:name="com.foo.bar.ActivityOne"
    android:theme="@olddogtheme"
    android:windowSoftInputMode="stateUnchanged"
    android:exported="true">

will result in :

<activity
    android:name="com.foo.bar.ActivityOne"
    android:screenOrientation="portrait"
    android:theme="@theme1"
    android:windowSoftInputMode="stateUnchanged"
    android:exported="true"/>

3. Disabling manifest merger altogether

See Disable Manifest Merger in Android Gradle Build.

android.applicationVariants.all { variant ->
    variant.processResources.manifestFile = file('src/main/AndroidManifest.xml')
    variant.processManifest.enabled=false
}

In what file do you put this?

At the end of your module's (not root project) build.gradle.

4. Are manifests from dependencies merged?

Yes they are (they're libraries).

Is there a way to block merging certain library manifests?

Not that I know of, sorry.

5. Any tutorials?

Depends on what are you trying to achive. So far it always worked for me out-of-the-box.

• e.g. http://www.myandroidsolutions.com/2014/04/10/android-gradle-manifest-merge/
• The manifest merger documentation (link below).

I don't know about any videos.

6. Anything I should be aware of?

You can check the generated manifest if you get suspicious about extra permissions etc. It's located in project/module/build/intermediates/manifests/full/[flavor]/build-type/AndroidManifest.xml.

Source: https://developer.android.com/studio/build/manifest-merge