Code faster on Android with Groovy and fastsnail !

fastsnail is a small Groovy library for Android, aiming at producing cleaner code, faster when building Android applications.

1. Setup

The first step is to enable Groovy support and add the library to your build.gradle file.

Here is how to do:

buildscript {
    repositories {
        mavenLocal()
        jcenter()
    }
    dependencies {
        // Groovy plugin
        classpath 'me.champeau.gradle:gradle-groovy-android-plugin:0.3.0'

        ...
    }
}

apply plugin: 'com.android.application'

android {
    ...
}

apply plugin: 'me.champeau.gradle.groovy-android'

repositories {
    jcenter()

    // fastsnail repository
    maven {
        url 'http://repo.grousset.fr/snapshots'
    }
}

...

dependencies {

    // Groovy version
    compile 'org.codehaus.groovy:groovy:2.4.0-beta-3:grooid'

    // fastsnail
    compile('fr.grousset.fastsnail:fastsnail:0.1-SNAPSHOT') {
        exclude group: 'org.codehaus.groovy' 
    }

    ...
}

2. Views and layouts injection

fastsnail provides annotations to inject views and layouts on activities and fragments.

On an Activity:

@CompileStatic
@InjectLayout(R.layout.activity_home)
class HomeActivity extends Activity {

    @InjectView(R.id.hello_text_view) TextView helloTextView

    protected void onCreate(Bundle savedInstanceState) {
    
    	// At this stage layout is set and views are injected
    
    	helloTextView.setText('Hello world from an Activity !!')
    }
}

On a Fragment:

@InjectLayout(R.layout.fragment_home)
public class HomeFragment extends Fragment {

    @InjectView(R.id.content_text_view) TextView contentTextView
	
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
                             
        // At this stage layout is set and views are injected

        contentTextView.setText('Hello from a Fragment !!!')

    }
}

3. Dependency injection

After setting up a config.json file (see Dependency Injection for details) like this:

{
    "components": {
        "myManager": {
            "className": "fr.grousset.fastsnail.test.MyManager",
            "singleton": true
        }
    }
}

It is possible to inject any object as collaborator of another object, like this:

class HomeActivity extends Activity {

    @InjectComponent MyManager myManager

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState)

        myManager.sayHello()
    }
}