Hilt, The DI Library For Android – Part1: Getting To Know

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<layout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">
    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@+id/ma_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".ui.MainActivity">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/ma_names_recycler"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="learn.shendy.learnhilt">

    <application
        android:name=".LearnHiltApp"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".ui.MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

app_build.gradle

apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'
apply plugin: 'kotlin-kapt'
apply plugin: 'dagger.hilt.android.plugin'

android {
    compileSdkVersion 29
    buildToolsVersion "30.0.0"

    defaultConfig {
        applicationId "learn.shendy.learnhilt"
        minSdkVersion 21
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    // NOTE: Projects that use both Hilt and data binding require Android Studio 4.0 or higher.
    // No need to enable dataBinding to use Hilt, I just prefer to use it.
    buildFeatures {
        dataBinding = true
    }
}

dependencies {

    // Hilt
    implementation "com.google.dagger:hilt-android:2.28-alpha"
    kapt "com.google.dagger:hilt-android-compiler:2.28-alpha"
    
    // Everything else
    implementation fileTree(dir: "libs", include: ["*.jar"])
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
    
    implementation 'androidx.recyclerview:recyclerview:1.1.0'
}

holder_name.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@+id/hn_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:id="@+id/hn_name_tv"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:text="Mommy"
            android:textColor="@android:color/black"
            android:textSize="18sp"
            android:padding="20dp"
            android:gravity="center"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

LearnHiltApp.java

@HiltAndroidApp
public class LearnHiltApp extends Application { 
  // 
}

MainActivity.java

@AndroidEntryPoint
public class MainActivity extends AppCompatActivity {

    @Inject
    NamesAdapter mNamesAdapter;

    private ActivityMainBinding mBinding;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mBinding = DataBindingUtil.setContentView(this, R.layout.activity_main);

        mBinding.maNamesRecycler.setLayoutManager(new LinearLayoutManager(this));
        mBinding.maNamesRecycler.setAdapter(mNamesAdapter);

        mNamesAdapter.update(buildMomNameList());
    }

    // MARK: Helper Methods

    private List<String> buildMomNameList() {
        return Arrays.asList(
                "Momzilla", "Maa", "Ammi", "MuNu", "Amma", "MooMoo",
                "Life", "Paradise", "Heaven", "Queen", "Fairy", "Momey",
                "Mommu", "Mumu", "Maaaaa", "Heartbeat", "Wonder Woman", "Yo Mama",
                "SuperWoman", "Big Mama"
        );
    }
}

NamesAdapter.java

public class NamesAdapter extends RecyclerView.Adapter<NamesAdapter.NameHolder> {

    private List<String> mNames = new ArrayList<>();

    @Inject
    public NamesAdapter() {}

    @NonNull
    @Override
    public NameHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        HolderNameBinding binding = HolderNameBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
        return new NameHolder(binding);
    }

    @Override
    public void onBindViewHolder(@NonNull NameHolder holder, int position) {
        String name = mNames.get(position);

        holder.mBinding.hnNameTv.setText(name);
    }

    @Override
    public int getItemCount() {
        return mNames.size();
    }

    public void update(List<String> names) {
        mNames.clear();
        mNames.addAll(names);
        notifyDataSetChanged();
    }

    class NameHolder extends RecyclerView.ViewHolder {
        HolderNameBinding mBinding;

        public NameHolder(@NonNull HolderNameBinding binding) {
            super(binding.getRoot());

            mBinding = binding;
        }
    }
}

project_build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath "com.android.tools.build:gradle:4.0.1"

        classpath 'com.google.dagger:hilt-android-gradle-plugin:2.28-alpha'
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}