Quadrant

Quadrant is a Gradle plugin for Android that makes navigation easy in multi-module projects.

There is no magic here. Quadrant simply parses your entire project's AndroidManifest.xml files, whichever module they are in, and generates for you a series of constants that contain your Activities' classnames.

object QuadrantConstants {
  
  const val MAIN_ACTIVITY: String = "com.gaelmarhic.quadrant.MainActivity"

  const val SECONDARY_ACTIVITY: String = "com.gaelmarhic.quadrant.SecondaryActivity"

  const val TERTIARY_ACTIVITY: String = "com.gaelmarhic.quadrant.TertiaryActivity"
}

This way you do not need any direct dependency to any Activity class inside of your project to be able to navigate to it. You can just use one of the constants generated by Quadrant in the following way:

val intent = Intent()
intent.setClassName(context, QuadrantConstants.MAIN_ACTIVITY)
startActivity(intent)

Download

To use Quadrant in your project, add the plugin to your buildscript:

buildscript {
    repositories {
        maven {
            url "https://plugins.gradle.org/m2/"
        }
    }
    dependencies {
        classpath "gradle.plugin.com.gaelmarhic:quadrant:$version"
    }
}

and then apply it in the build.gradle file of one of your Android modules (app or library):

apply plugin: "com.gaelmarhic.quadrant"

If you prefer to use the Plugins DSL, you have to edit your settings.gradle, first, and set the repositories where Gradle should resolve plugins from (needs to be at top of file):

pluginManagement {
    repositories {
        gradlePluginPortal()
        google()
    }
}

This tells Gradle to resolve plugins from the Gradle plugin repo and from the Google maven repo. This is necessary, because Quadrant depends on the Android Gradle plugin, which can only be resolved from the latter one.

Aftwards you can use the Quadrant plugin with:

plugins {
    id "com.gaelmarhic.quadrant" version "$version"
}

ATTENTION: It is strongly recommended to apply Quadrant to only one module of your project in order to not harm your build time. As an example, you could create a navigation module which will contain all your navigation-related code and apply Quadrant only to that one.

Prerequisites

In order for Quadrant to work properly, by default, there must be no duplicated Activity names across the project. However, there is an option to allow name duplication across modules for multi-module apps. Check the quadrantConfig.perModule flag.

Addressability

By default, and just by applying the plugin, Quadrant will generate a classname constant for each and every Activity inside your project.

However, in order to not get polluted by classname constants you may not need, Quadrant provides you with some configuration options.

First of all, you can decide of an Activity's addressability, and therefore whether its classname constant is generated or not, by applying, to its <activity> tag or to its parent <application> tag, one of the following snippets:

<meta-data
    android:name="addressable"
    android:value="true" />

or

<meta-data
    android:name="addressable"
    android:value="false" />

You can also decide to not generate any constant by default, just by pasting the following snippet in the build.gradle file where Quadrant is applied:

quadrantConfig {
    generateByDefault false
}

Applying an addressable <meta-data> directly on an <activity> tag will force this Activity's addressability, no matter what the parent <application> tag and the generateByDefault configuration say.

On the other hand, applying an addressable <meta-data> directly on an <application> tag will force this <application> tag's children Activities's addressability (unless those children Activities have an addressable <meta-data> themselves), no matter what the generateByDefault configuration say.

Here are a couple of examples with different combinations:

Example 1

build.gradle

quadrantConfig {
    generateByDefault false
}

AndroidManifest.xml

<application>

    <activity android:name="com.gaelmarhic.quadrant.MainActivity">

        <meta-data
            android:name="addressable"
            android:value="true" />

    </activity>

    <activity android:name="com.gaelmarhic.quadrant.SecondaryActivity" />

</application>

In this example, only the classname constant of the MainActivity will be generated.

Example 2

build.gradle

quadrantConfig {
    generateByDefault true
}

AndroidManifest.xml

<application>

    <meta-data
        android:name="addressable"
        android:value="false" />

    <activity android:name="com.gaelmarhic.quadrant.MainActivity" />

    <activity android:name="com.gaelmarhic.quadrant.SecondaryActivity" />

    <activity android:name="com.gaelmarhic.quadrant.TertiaryActivity">

        <meta-data
            android:name="addressable"
            android:value="true" />

    </activity>

</application>

In this example, only the classname constant of the TertiaryActivity will be generated.

ATTENTION: You cannot have conflicts of addressable <meta-data> for a same <activity> tag or a same <application> tag, whether it is in the same AndroidManifest.xml file or in AndroidManifest.xml files from different source sets.

Ignoring <activity> tags

There may be some cases when you will want or need Quadrant to not take into account some <activity> tags at all. For example, this may happen with some third-party libraries that make you declare their Activity in your own AndroidManifest.xml files.

If this occurs, you just have to paste the following snippet inside the <activity> tag that you want or need to ignore:

<meta-data
    android:name="quadrant"
    android:value="ignore" />

Example

<activity android:name="com.gaelmarhic.quadrant.MainActivity">

    <meta-data
        android:name="quadrant"
        android:value="ignore" />

</activity>

In this example, MainActivity will literally be ignored by Quadrant.

Generated file(s)

Quadrant will, by default, generate all the classname constants in a unique file called QuadrantConstants.

However, Quadrant provides you with a configuration option that allows you to have the constants generated in different files named after the different modules. You just need to paste the following snippet in the build.gradle file where Quadrant is applied:

quadrantConfig {
    perModule true
}

License

Copyright 2020 Gaël Marhic

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.