Meow Framework MVVM Android/Kotlin

A Framework that simplify developing MVVM Architecture and Material Design in Android with Kotlin language including useful Extensions and Sample Application. This Framework has some tools for Retrofit and OKHttp and Coroutine for calling REST API requests.
Dynamic Localization and Day/Night Theme & Meow Custom Widgets are another features.

📱 Sample Application

We suggest you to install Meow-Sample.apk to be familiar with Meow Framework.

😍 Donate & Support

We are developing this framework in open source community without financial planning but the maintenance & preparing updates at periodic times is Time-consuming. If you like this project and you want to give us peace of mind, you can support us by clicking this button :

🛠 Setup

implementation("com.etebarian:meow-framework-mvvm:0.10.2")

After adding library, some of most useful libraries (such as Androidx AppCompat , Coroutine , Glide , Kodein , Kotlinx Serialization , Material Components , Moshi , Navigation Components , Retrofit ) will be added in your app. So you would'nt need to add this libraries manually.

List of dependencies can be found in meow.AppConfig.kt in Dependencies Object.

Check out build.gradle.kts in Sample module to avoid any issues that related to setup & adding Framework. We recommend that use Kotlin DSL Gradle instead of Groovy . That is not Buggy 😊.

Enable androidx in gradle.properties.

android.useAndroidX=true
android.enableJetifier=true

Remember that you'll need to enable Java 8 & DataBinding & Kotlin Kapt in your app module build.gradle.

📃 Table of Contents

• 💡 Getting Started

  • Initialization : How to have a MeowApp.
  • Meow Controller 🐈 : Trust this CAT.
  • MVVM Architecture : Get to know this architecture.
  • Accessing Views with DataBinding : Forget findViewById().

• 📶 REST API : Retrofit + OKHttp + Coroutine + Moshi

  • Create Api that extends MeowApi : A new way to connect server.
  • Common API Flow/Patterns : Some predefined patterns for REST APIs.
  • Sample Index Api : A Sample for filling RecyclerView from JSON Data.

• 🧩 Meow KTX (Kotlin Extensions)

• Ⓜ Material Design Setup

• 🎨 Material Components

• 🌌 Meow Custom Widgets

• 🖐 Contributing

💡 Getting Started

We assume that you know MVVM architecture, but if you have some problems in understanding its, this Articles can help you.

🎮 Initialization

Create your application class which extends MeowApp and set it in AndroidManifest.xml. Dependency Injection in MVVM architecture is necessary, so we use Kodein-DI Framework. You'll need to define appModule for View Models. Update application class like below :

class App : MeowApp() {

    // Create a kodein module.
    val appModule = Module("App Module", false) {
        // Provide object of SomeOfClass(such as View Models) in Kodein with bind() function.
        // bind() from singleton { SomeOfClass(instance()) }
    }

   // Source is `KodeinAware` interface.
    override val kodein = Kodein.lazy {
        // Import org.kodein.di.Kodein.*
        bind() from singleton { kodein.direct }
        bind() from singleton { this@App }
        import(androidXModule(this@App))
        import(meowModule) // Important
        import(appModule)
    }
}

🐱 Meow Controller

This Framework has two Highlighted Features :

• Dynamic Day/Night Theme to switch from LIGHT to DARK mode.
• Dynamic Localization to change language , currency formatting , date formatting of app at Realtime.

to use above features, you'll need to define your MeowController.

MeowController is a class that controls some features in app such as above. If you want to use avoidException in your app, this class can controls Exception Handlers with onException property.

Update your application class like this :

class App : MeowApp() {
    // Layout Direction would be set automatically by Android System.
    // (Example: "en": LayoutDirection.LTR  "fa": LayoutDirection.RTL).
    
    // Our Primary Sample app's language is English.
    override fun getLanguage(context: Context?) = "en" // or any language such as ("fa","fr","ar",etc.)     
    
    // Our Sample app's theme is set by Android System Light/Dark (Day/Night) mode.  
    override fun getTheme(context: Context?) =
        if (context.isNightModeFromSettings()) MeowController.Theme.NIGHT else  MeowController.Theme.DAY
         
    override fun onCreate() {
        super.onCreate()
        bindMeow { // Import it from meow package.
            it.isDebugMode = BuildConfig.DEBUG
            // Set other properties here.
            it.onException = { // Only non-fatal error
                // Log to Fabric or any other Crash Management System. Just use `avoidException` instead of `try{}catch{}`
            }
        } 
    }
}

You can update language and theme from UI Thread by using MeowController global instance.

import meow.controller
  
controller.updateLanguage(meowActivity, string)
controller.updateTheme(meowActivity, theme)

The Sample Application has above features. try to install Meow-Sample.apk .

📐 MVVM Architecture

MVVM is Model-View-ViewModel that we define it in Android App as Data Model - View (Activity, Fragment, DialogFragment, BottomSheetDialogFragment) - MeowViewModel.

Follow below steps to have an activity with MVVM Architecture.

1. Create your ViewModel that extends MeowViewModel.

class MainViewModel(app: App): MeowViewModel(app)

2. Provide your View Model in appModule in App.

val appModule = Module("App Module", false) {
    bindAutoTag<MainViewModel>() with provider {
        MainViewModel(kodein.direct.instance())
    }
}

bindAutoTag() was imported from meow.ktx.* package.

3. Create XML layout with DataBinding structure.

<layout>
    <data>
        <variable
            name="viewModel"
            type="MainViewModel" />
    </data>
    <LinearLayout /> <!-- or another View -->
</layout>

4. Create Activity/Fragment ( extends MeowActivity/MeowFragment ) + DataBinding + ViewModel.

‍‍‍MainActivity is a sample activity that needs Kodein Dependency Injection and ViewDataBinding and View Model. See this example :

class MainActivity : MeowActivity<ActivityMainBinding>() {
    // ActivityMainBinding is generated by Androidx Lifecycle DataBinding Utils.
    
    private val viewModel: MainViewModel by instanceViewModel()
    override fun layoutId() = R.layout.activity_main
    
    override fun initViewModel() {// Set View Model in binding.
        binding.viewModel = viewModel    
    }
}

Accessing Views with DataBinding

You can access views like this code :

<com.google.android.material.appbar.MaterialToolbar
    android:id="@+id/toolbar"
    style="@style/Meow.Toolbar" />

class MainActivity : MeowActivity<ActivityMainBinding>() {
    override fun layoutId() = R.layout.activity_main
    override fun onCreate(savedInstanceState: Bundle?) {
        // ...
        binding.toolbar.title = "custom_title" // Use binding variable 
    }
}

Now you have an Activity with MVVM architecture. In above sample, you can replace MeowActivity with MeowFragment to have MVVM Fragment.

📶 REST API : Retrofit + OKHttp + Coroutine + Moshi

Meow Framework provides some tools to call Server REST API actions from Android App with Retrofit. Creating client connections will be with OKHttp . Moshi helps us to serialize json responses. We replaced RxJava with Coroutine for multi thread handling.

Create Api that extends MeowApi

class AppApi(
    var app: App,
    baseUrl : String = "http://api-url.any/api/v1/"
): MeowApi(baseUrl)

Common API Flow/Patterns

We'll show you how to call a request to server and get response from it. Then Data has been shown in UI by parsing Data. Some of actions that is related to REST API can be have a flow/pattern. We define this patterns as :

• Index : Response with simple request from server can be parsed as List of Data Model.
• Detail : Response with simple request from server can be parsed as a Data Model.
• Form : Response with advanced request (send a form) from server can be parsed as a Data Model.

Sample Index Api

For example, server gives this JSON response when we call /api/v1/persons with GET method :

[
  {
    "id":1,
    "username":"oneHamidreza",
    "alias":"Hamidreza Etebarian"
  },
  
  {
    "id":2,
    "username":"samdh82",
    "alias":"Ali Modares"
  }
]

Data Model

Create a data class for JSON response which uses Moshi @Json annotation.

@JsonClass(generateAdapter = true)
data class Person(
    @Json(name = "id") var id: Int = 0,
    @Json(name = "username") var username: String? = null,
    @Json(name = "alias") var alias: String? = null) {
    
    // RecyclerView List Adapter requires DiffCallBack.
    class DiffCallback : DiffUtil.ItemCallback<Person>() {
        override fun areItemsTheSame(oldItem: Person, newItem: Person) = oldItem.id == newItem.id
        override fun areContentsTheSame(oldItem: Person, newItem: Person) = oldItem == newItem
    }
}

Retrofit API Interface

Define an interface containing Rest API actions. Meow Framework uses Coroutine library to calling Rest API actions, so you must write suspend prefix for functions.

interface PersonApi {
    @GET("persons") // Don't need to write absolute path. OKHTTP appends this string at end of your baseUrl API.
    suspend fun getPersonIndex(): List<Person>
}

Call API action from ViewModel by using safeCallApi(). Update your ViewModel class like this :

class PersonIndexViewModel(override var app: App) : MeowViewModel(app) {
    // Define LiveData variables. use `SingleLiveData` to observe only when changed.
    var eventLiveData = SingleLiveData<MeowEvent<*>>()
    var listLiveData = SingleLiveData<List<Person>>()
    var customLiveData = SingleLiveData<String>()
    
    fun callApi() {
        safeCallApi(
            liveData = eventLiveData,   
            apiAction = { AppApi(app).createServiceByAdapter<PersonApi>().getPersonIndex() }
        ) { _, it ->
            // If connection was Success and Retrofit can parse json data as list of models, this line will be run.
            // Otherwise MeowEvent.Api.Error will be posted into eventLiveData.
            
            // You can observe it manually or use MeowFlow.
            listLiveData.postValue(it)
        }
    }
}

XML Layout

Create activity_sample_index.xml which has RecyclerView to showing items as List.

<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable
            name="viewModel"
            type="PersonIndexViewModel" />
    <!-- Remember that viewModel type must be with package -->
    </data>
    
    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
        
        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recyclerView"
            style="@style/Meow.RecyclerView.Linear"
            meow_items="@{viewModel.listLiveData}" />
            
        <meow.widget.MeowProgressBar
            android:id="@+id/progressbar"
            style="@style/Meow.ProgressBar.Medium.Primary" />
     
    </FrameLayout>
</layout>

MeowActivity/MeowFragment + MeowFlow

Use MeowFlow to handle events from ViewModel automatically.

class SampleIndexActivity : MeowActivity<ActivitySampleIndexBinding>() {
    //...
    
    private val viewModel by instance<PersonIndexViewModel>()
    override fun layoutId() = R.layout.activity_sample_index
    
    override fun initViewModel() {
        binding.viewModel = viewModel
        callApiAndObserve()    
    }
    
    private fun callApiAndObserve() {
        MeowFlow.GetDataApi<Person>(this) { // You must pass the type of API response. For Example : `Person`.
            viewModel.callApi()
        }.apply {
            errorHandlerType = MeowFlow.ErrorHandlerType.TOAST // Error handling will be with toast().
            progressBarInterface = binding.progressbar
        }.observeForIndex(viewModel.eventLiveData, viewModel.listLiveData)
        
        // Optional - call safeObserve function for observe changes of liveData safely.
        viewModel.customLiveData.safeObserve(this) {
            // Access the value of liveData with it parameter.
        }
    }
}

MeowFlow is a helper class that observes eventLiveData and it handles errors from API automatically. You can set error handling with errorHandlerType. Supported types : TOAST , SNACKBAR , EMPTY_STATE. For example, when errorHandlerType is Toast errors has been shown in toast form. See strings_error.xml to edit error messages.

Show API response into RecyclerView

item_person.xml describes the layout of each row of list and you can set properties with DataBinding structure. Define layout like this :

<layout>
    <data>
        <variable
            name="model"
            type="Person" />           
    </data> 

    <LinearLayout>
        <TextView  android:text="@{model.alias}" />
    </LinearLayout>
</layout>  

We suggest you to use MeowAdapter. Let's take a look at this sample :

class PersonAdapter : MeowAdapter<Model, ViewHolder>(Person.DiffCallback()) {
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val binding = ItemPersonBinding.inflate(LayoutInflater.from(parent.context), parent, false)
        return MeowViewHolder(binding.root) { position, model ->
            binding.let {
                it.setVariable(BR.model, model)
                it.executePendingBindings()
            }
        }
    }
}

Finally bind adapter to RecyclerView.

class PersonIndexActivity : MeowActivity<ActivitySampleIndexBinding>(){
    override fun onCreate(savedInstanceState: Bundle?) {
        //...
        binding.recyclerView.adapter = PersonAdapter()
    }
}

Now you have a activity that connect to REST API and parse the response (if the response code is HttpCode.OK (200)) and it shows items into a RecyclerView as a list. Above sample can be used for other types of REST API patterns/flows (such as Detail ,Form). for more details see API Package in Sample module.

🧩 Meow KTX (Kotlin Extensions)

We have developed some Kotlin Extensions that can be help us in building Android Apps. Just import meow.ktx package which include the following :

• 🧩 Androidx Extensions
• 💵 Currency Extensions
• 📅 Date Extensions
• 📂 File Extensions
• 📇 JSON Extensions
• 💉 Kodein Extensions
• 💎 Kotlin Extensions
• 📃 Log Extensions
• 🧮 Math Extensions
• 📶 Network Extensions
• 🚦 Permission Extensions
• 📬 Shared Preferences Extensions
• 🍟 Snackbar Extensions
• 🧬 String Extensions
• 🚂 System Extensions
• 🍞 Toast Extensions
• ✅ Validate Extensions

Ⓜ Material Design Setup

Update App Theme in styles.xml with DayNight Material Theme. More details are at Official Material Design Site.

<style name="AppTheme" parent="Theme.MaterialComponents.DayNight.NoActionBar">
    <!-- Original AppCompat attributes. -->
    <!-- Define colors in colors.xml -->
    
    <item name="colorPrimary">YOUR_PRIMARY_COLOR</item>
    <item name="colorSecondary">YOUR_SECONDARY_COLOR</item>
        
    <item name="android:colorBackground">@color/meow_background</item>
    <!-- New MaterialComponents attributes. -->
    <item name="colorPrimaryVariant">YOUR_PRIMARY_VARIANT_COLOR</item>
    <item name="colorSecondaryVariant">YOUR_SECONDARY_VARIANT_COLOR</item>
    <item name="colorOnPrimary">YOUR_ON_PRIMARY_COLOR</item>
    <item name="colorOnSecondary">YOUR_ON_SECONDARY_COLOR</item>
    <item name="colorSurface">@color/meow_surface</item>
    <item name="colorOnSurface">@color/meow_on_surface</item>
    <item name="colorOnBackground">@color/meow_on_background</item>
    <item name="colorError">@color/meow_error</item>
    <item name="colorOnError">@color/meow_on_error</item>
    <item name="scrimBackground">@color/mtrl_scrim_color</item>
</style>

🖌 Material Text Styles + Font by using Meow.TextAppearance Style

Just do same as styles_text_appearances.xml.

You must apply styles in AppTheme.

<style name="AppTheme" parent="Theme.MaterialComponents.DayNight.NoActionBar" >
  <item name="textAppearanceHeadline1">@style/App.TextAppearance.Headline1</item>
  <item name="textAppearanceHeadline2">@style/App.TextAppearance.Headline2</item>
  <item name="textAppearanceHeadline3">@style/App.TextAppearance.Headline3</item>
  <item name="textAppearanceHeadline4">@style/App.TextAppearance.Headline4</item>
  <item name="textAppearanceHeadline5">@style/App.TextAppearance.Headline5</item>
  <item name="textAppearanceHeadline6">@style/App.TextAppearance.Headline6</item>
  <item name="textAppearanceSubtitle1">@style/App.TextAppearance.Subtitle1</item>
  <item name="textAppearanceSubtitle2">@style/App.TextAppearance.Subtitle2</item>
  <item name="textAppearanceBody1">@style/App.TextAppearance.Body1</item>
  <item name="textAppearanceBody2">@style/App.TextAppearance.Body2</item>
  <item name="textAppearanceCaption">@style/App.TextAppearance.Caption</item>
  <item name="textAppearanceButton">@style/App.TextAppearance.Button</item>
  <item name="textAppearanceOverline">@style/App.TextAppearance.Overline</item>
</style>

🎨 Material Components

Alerts

You can show Alert Dialog with alert() function in MeowActivity/MeowFragment.

fun testAlert() {
    alert(R.string.alert_title,R.string.alert_message)
        .setPositiveButton(R.string.ok) { d, _ ->
            toastL(R.string.alerts_warn_ok_clicked)
            d.dismiss()
        }
        .setNegativeButton(R.string.cancel) { d, _ ->  
            toastL(R.string.alerts_warn_cancel_clicked)
            d.dismiss()
        }.show()
}

Loading Alert

A Dialog with MeowLoadingView to showing progress bar with text into Dialog.

fun testLoadingAlertDialog() {
    loadingAlert(R.string.loading_title_custom).show()
}

Learn more about it at AlertsFragment.kt.

Button

There are some customized styles that is related to Material Button.

Style	Usage
Meow.Button	Regular Button with primary background color
Meow.Button.Outlined	Outlined Button with transparent background color and stroke_color.xml outline color
Meow.Button.Flat	Flat Button with transparent background color
Meow.Button.Unelevated	Regular Button with primary background color with 0dp elevation
Meow.Button.IconOnly	A Meow Button that shows has not text

Use it like this in XML Layout :

<LinearLayout>
    <Button
        style="@style/Meow.Button"
        android:text="SomeRegularButton" />
    <Button
        style="@style/Meow.Button"
        android:textColor="?colorOnSecondaryVariant"
        android:text="SomeCustomizedButton"
        app:backgroundTint="?colorSecondaryVariant" />
</LinearLayout>

Learn more about it at Material Card Component and fragment_cards.xml.

CardView

There are some customized styles that is related to Material CardView.

Style	Usage
Meow.CardView	Regular Card with surface background color
Meow.CardView.Outlined	Outlined Card with surface background color and stroke_color.xml outline color

Use it like this in XML Layout :

<com.google.android.material.card.MaterialCardView
    style="@style/Meow.CardView"
    app:contentPadding="16dp" >
        <!-- Place your views here -->
    </com.google.android.material.card.MaterialCardView>

Learn more about it at Material Card Component and fragment_cards.xml.

Checkbox

There are some customized styles that is related to Material CheckBox.

Style	Usage
Meow.Checkbox	Checkbox with accent_color button tint
Meow.Checkbox.Primary	Checkbox with primary button tint
Meow.Checkbox.Secondary	Checkbox with secondary button tint
Meow.Checkbox.OnPrimary	Checkbox with onPrimary button tint & textColor
Meow.Checkbox.OnSecondary	Checkbox with onSecondary button tint & textColor

Use it like this in XML Layout :

<com.google.android.material.checkbox.MaterialCheckBox
    style="@style/Meow.Checkbox"
    android:text="@string/checkbox_text" />  

Learn more about it at Material Checkbox Component and fragment_checkboxes.xml.

Floating Action Button

Use it like this in XML Layout :

<androidx.coordinatorlayout.widget.CoordinatorLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >
    
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        style="@style/Meow.RecyclerView.Linear"
        app:meow_items="@{viewModel.listLiveData}" />
        
    <com.google.android.material.floatingactionbutton.FloatingActionButton
        style="@style/Meow.FloatingActionButton"
        android:onClick="@{viewModel::onClickedFab}"
        app:icon="@drawable/ic_add"
        app:layout_anchor="@id/recyclerView"
        app:layout_anchorGravity="bottom|center_horizontal" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Learn more about it at Material Floating Action Button Component and fragment_fab_simple.xml.

Extended Floating Action Button

A FAB that supports android:text property. Use it like this in XML Layout :

<com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton
    style="@style/Meow.FloatingActionButton.Extended"
    android:onClick="@{viewModel::onClickedFab}"
    android:text="@string/fab_extended_text"
    app:icon="@drawable/ic_add"
    app:layout_anchor="@id/recyclerView"
    app:layout_anchorGravity="bottom|center_horizontal" />

Learn more about it at Material Extended Floating Action Button Component and fragment_fab_simple.xml.

Radio Group

There are some customized styles that is related to Material Radio Group.

Style	Usage
Meow.RadioGroup.Horizontal	RadioGroup with Horizontal Radio Buttons
Meow.RadioGroup.Vertical	RadioGroup with Vertical Radio Buttons

Radio Button

There are some customized styles that is related to Material Radio Button.

Style	Usage
Meow.RadioButton.Vertical	Vertical RadioButton with accent_color button tint
Meow.RadioButton.Horizontal	Horizontal RadioButton with accent_color button tint
Meow.RadioButton.Vertical.Primary	Vertical RadioButton with primary button tint
Meow.RadioButton.Horizontal.Primary	Horizontal RadioButton with primary button tint
Meow.RadioButton.Vertical.Secondary	Vertical RadioButton with secondary button tint
Meow.RadioButton.Horizontal.Secondary	Horizontal RadioButton with secondary button tint
Meow.RadioButton.Vertical.OnPrimary	Vertical RadioButton with onPrimary button tint & textColor
Meow.RadioButton.Horizontal.OnPrimary	Horizontal RadioButton with onPrimary button tint & textColor
Meow.RadioButton.Vertical.OnSecondary	Vertical RadioButton with onSecondary button tint & textColor
Meow.RadioButton.Horizontal.OnSecondary	Horizontal RadioButton with onSecondary button tint & textColor

Use it like this in XML Layout :

<RadioGroup style="@style/Meow.RadioGroup.Vertical">
    <com.google.android.material.radiobutton.MaterialRadioButton
        style="@style/Meow.RadioButton.Vertical.Primary"
        android:text="@string/radio_buttons_option_a" />
             
    <com.google.android.material.radiobutton.MaterialRadioButton
        style="@style/Meow.RadioButton.Vertical.Primary"
        android:text="@string/radio_buttons_option_b" />
</RadioGroup>

Learn more about it at Material Radio Button Component and fragment_radio_buttons.xml.

Snack Bars

You can show Snack Bars with snackL() or snackS() functions in MeowActivity/MeowFragment.

fun testSnackbars(){
    // Shows Snack Bars with LENGTH_SHORT.  
    snackS(R.string.snackbars_message)
    // Shows Snack Bars with LENGTH_LONG.
    snackL(R.string.snackbars_message)
    // Shows Snack Bars with LENGTH_INDEFINITE.
    snackI(R.string.snackbars_message)
      
    // Shows Snack Bars with LENGTH_LONG with action button.
    snackL(
        message = R.string.snackbars_message,    
        resActionText = R.string.snackbars_action,
        
        // Optional - if you want to set custom textAppearances to message and action, set this attributes.
        messageTextAppearanceId = R.style.textAppearance_Snack_Message,
        actionTextAppearanceId = R.style.textAppearance_Snack_Action
    ) {
        // Callback for action button click
    }    
}

Learn more about it at SnackBarsFragment.

Switch

There are some customized styles that is related to Material Switch.

Style	Usage
Meow.Switch	Switch with accent_color button tint
Meow.Switch.Primary	Switch with primary button tint
Meow.Switch.Secondary	Switch with secondary button tint
Meow.Switch.OnPrimary	Switch with onPrimary button tint & textColor
Meow.Switch.OnSecondary	Switch with onSecondary button tint & textColor

Use it like this in XML Layout :

<com.google.android.material.switchmaterial.SwitchMaterial
    style="@style/Meow.Switch"
    android:text="@string/switch_text" />

Learn more about it at Material Switch Component and fragment_switches.xml.

TabLayout + ViewPager2

If you want to show contents into a ViewPager, we recommend to use ViewPager2. TabLayout is the indicator of ViewPager state. Follow below steps to have a View with Swipe Gesture.

1. Define XML layout like this :

<layout>
    <data />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        
        <com.google.android.material.tabs.TabLayout
            android:id="@+id/tabLayout"
            style="@style/Meow.TabLayout.Surface" />
            
        <androidx.viewpager2.widget.ViewPager2
            android:id="@+id/viewpager"
            style="@style/Meow.ViewPager" />    
    
    </LinearLayout>  
</layout>  

2. Create Custom Pager Adapter that extends MeowPagerAdapter

class MyPagerAdapter(
    fragmentManager: FragmentManager,
    lifecycle: Lifecycle) : MeowPagerAdapter(fragmentManager, lifecycle) {
        // Replace this with the array of Fragments that you want to show into ViewPager.
        private val fragmentArray = Array<Fragment>(3) { ChildFragment.newInstance(it) }
        override fun getFragments() = fragmentArray
}

3. Bind Adapter to ViewPager2 & Attach TabLayout to ViewPager2

fun onCreate(savedInstanceState: Bundle?) {
    // ...
    binding.apply {
        binding.viewPager.adapter = MyPagerAdapter(childFragmentManager, lifecycle)
        TabLayoutMediator(tabLayout, viewpager) { tab, position ->
            tab.text = "Tab Title #" + (position + 1) // Set Tab titles here.
        }.attach()
        
        // Optional - If you want to show Material Badge on TabLayout.
        tabLayout.getTabAt(0)?.orCreateBadge?.apply {
            isVisible = true
            number = 10
        }
    }
}  

Now you have ViewPager2 + TabLayout in an Activity/Fragment.

There are some customized styles that is related to Material TabLayout.

Style	Usage
Meow.TabLayout.Surface	TabLayout with surface background color
Meow.TabLayout.Primary	TabLayout with primary background color
Meow.TabLayout.Secondary	TabLayout with primary background color
Meow.TabLayout.PrimarySurface	TabLayout with primary background color in DAY mode and surface background color in NIGHT Mode

Learn more about it at Material TabLayout Component.

TextView

Use it like this in XML Layout :

<TextView
    style="@style/Meow.TextView"
    android:text="@string/some_text"
    android:textAppearance="?textAppearanceBody1"
    android:textColor="@color/on_background_high" />

Learn more about it at fragment_textviews.xml.

Colors for texts based on Material Colors which contains EMPHASIS_HIGH , EMPHASIS_MEDIUM , DISABLED states.

Color	Value
@color/on_background_high	onBackground color with %87 transparency
@color/on_background_medium	onBackground color with %60 transparency
@color/on_background_disabled	onBackground color with %38 transparency
@color/on_surface_high	onSurface color with %87 transparency
@color/on_surface_medium	onSurface color with %60 transparency
@color/on_surface_disabled	onSurface color with %38 transparency
@color/on_primary_high	onPrimary color with %87 transparency
@color/on_primary_medium	onPrimary color with %60 transparency
@color/on_primary_disabled	onPrimary color with %38 transparency
@color/on_secondary_high	onSecondary color with %87 transparency
@color/on_secondary_medium	onSecondary color with %60 transparency
@color/on_secondary_disabled	onSecondary color with %38 transparency

Top App Bar using Material Toolbar

Use it like this in XML Layout :

<layout>
    <data/>
    <androidx.coordinatorlayout.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">    

         <com.google.android.material.appbar.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:liftOnScroll="true">
            
            <com.google.android.material.appbar.MaterialToolbar
                android:id="@+id/toolbar"
                style="@style/Meow.Toolbar.Surface" />
            
          </com.google.android.material.appbar.AppBarLayout>  
      
    <!-- Main Layout -->
    
    </androidx.coordinatorlayout.widget.CoordinatorLayout>
</layout>

There are some customized styles that is related to Material Toolbar.

Style	Usage
Meow.Toolbar.Surface	Toolbar with surface background color
Meow.Toolbar.PrimarySurface	Toolbar with primary background color in DAY mode and surface background color in NIGHT Mode
Meow.Toolbar.Primary	Toolbar with primary background color
Meow.Toolbar.Secondary	Toolbar with secondary background color

Learn more about it at Material Top App Bars Component.

🌌 Meow Custom Widgets

Meow Circle ImageView

Meow CircleImageView Attributes:

Attributes	Descriptions
meow_strokeColor	The stroke color of image
meow_strokeWidth	The stroke width of image

Use it like this in XML Layout :

<meow.widget.MeowCircleImageView
    android:layout_width="56dp"
    android:layout_height="56dp"
    app:meow_strokeColor="@color/white"
    app:meow_strokeWidth="2dp"
    app:srcCompat="@drawable/avatar" />

Learn more about it at fragment_imageviews.xml.

Meow Dash View

There are some styles that is related to Dash View.

Style	Usage
Meow.Dash.Horizontal	DashView with Horizontal orientation
Meow.Dash.Horizontal.Primary	DashView with Horizontal orientation and primary color
Meow.Dash.Horizontal.PrimaryVariant	DashView with Horizontal orientation and PrimaryVariant color
Meow.Dash.Horizontal.PrimarySurface	DashView with Horizontal orientation and PrimarySurface color
Meow.Dash.Horizontal.Secondary	DashView with Horizontal orientation and secondary color
Meow.Dash.Horizontal.SecondaryVariant	DashView with Horizontal orientation and SecondaryVariant color
Meow.Dash.Horizontal.OnPrimary	DashView with Horizontal orientation and OnPrimary color
Meow.Dash.Horizontal.OnSecondary	DashView with Horizontal orientation and OnSecondary color
Meow.Dash.Horizontal.OnSurface	DashView with Horizontal orientation and OnSurface color
Meow.Dash.Vertical	DashView with Vertical orientation
Meow.Dash.Vertical.Primary	DashView with Vertical orientation and primary color
Meow.Dash.Vertical.PrimaryVariant	DashView with Vertical orientation and PrimaryVariant color
Meow.Dash.Vertical.PrimarySurface	DashView with Vertical orientation and PrimarySurface color
Meow.Dash.Vertical.Secondary	DashView with Vertical orientation and secondary color
Meow.Dash.Vertical.SecondaryVariant	DashView with Vertical orientation and SecondaryVariant color
Meow.Dash.Vertical.OnPrimary	DashView with Vertical orientation and OnPrimary color
Meow.Dash.Vertical.OnSecondary	DashView with Vertical orientation and OnSecondary color
Meow.Dash.Vertical.OnSurface	DashView with Vertical orientation and OnSurface color

Meow Dash Attributes:

Attributes	Descriptions
meow_dash_gap	Dash Gap
meow_dash_length	Dash length
meow_dash_thickness	Dash thickness
meow_dash_color	Dash color

Use it like this in XML Layout :

 <meow.widget.MeowDashView
    app:meow_dash_gap="4dp"
    app:meow_dash_length="8dp"
    app:meow_dash_thickness="2dp" />

Learn more about it at fragment_dash.xml.

Meow Divider

There are some styles that is related to Divider.

Style	Usage
Meow.Divider.Horizontal	Divider with Horizontal orientation
Meow.Divider.Vertical	Divider with Vertical orientation
Meow.Divider.Horizontal.OnPrimary	Divider with Horizontal orientation and primary divider background type
Meow.Divider.Horizontal.OnSecondary	Divider with Horizontal orientation and secondary divider background type
Meow.Divider.Horizontal.OnSurface	Divider with Horizontal orientation and surface divider background type
Meow.Divider.Vertical.OnPrimary	Divider with Vertical orientation and primary divider background type
Meow.Divider.Vertical.OnSecondary	Divider with Vertical orientation and secondary divider background type
Meow.Divider.Vertical.OnSurface	Divider with Vertical orientation and surface divider background type

Meow Divider Attributes:

Attributes	Descriptions
meow_orientation	Orientation: vertical or horizontal
meow_background_type	Types: background,surface,secondary,primary

Use it like this in XML Layout :

You just need use style.😉

<meow.widget.MeowDivider style="@style/Meow.Divider.Horizontal" />

Learn more about it at fragment_dividers.xml.

Meow Empty State

There are some styles that is related to Empty State.

Style	Usage
Meow.EmptyState	EmptyState default style with icon size and icon tint
Meow.EmptyState.OnBackground	EmptyState with title and description OnBackground color
Meow.EmptyState.OnPrimary	EmptyState with title and description OnPrimary color
Meow.EmptyState.OnSecondary	EmptyState with title and description OnSecondary colore
Meow.EmptyState.OnSurface	EmptyState with title and description OnSurface color

Meow Empty state Attributes:

Attributes	Descriptions
meow_icon	Icon resource
meow_iconSize	Icon size
meow_iconTint	Icon tint color
meow_title	Title text
meow_titleTextColor	Title text color
meow_desc	Description text
meow_descTextColor	Description text color
meow_primaryActionText	Button text

Use it like this in XML Layout :

<meow.widget.MeowEmptyState
    android:id="@+id/emptyState"
    style="@style/Meow.EmptyState.OnBackground" />

Not Completed yet!.

Meow Hint Button

There are some styles that is related to Hint Button.

Style	Usage
Meow.HintButton	HintButton default style with icon color

Meow HintButton Attributes:

Attributes	Descriptions
meow_hint	Hint text
meow_hintColor	Hint text color
meow_hintTextAppearance	Hint textAppearance
meow_title	Title text
meow_titleColor	Title text color
meow_titleTextAppearance	Title textAppearance
meow_icon	Icon resource
meow_iconColor	Icon color

Use it like this in XML Layout :

<meow.widget.MeowHintButton
    style="@style/Meow.HintButton"
    app:meow_hint="@string/date"
    app:meow_icon="@drawable/ic_date"
    app:meow_title="@string/date_num" />

Learn more about it at fragment_form.xml.

Meow PinView

There are some styles that is related to PinView.

Style	Usage
Meow.PinView.Filled	PinView Filled box style
Meow.PinView.Outlined	PinView Outlined box style

Meow PinView Attributes:

Attributes	Descriptions
meow_hint	Hint text
meow_hintColor	Hint text color
meow_hintTextAppearance	Hint textAppearance
meow_count	Length of pin (box count)
meow_textColor	Boxes text color
meow_textAppearance	Boxes textAppearance
meow_icon	Icon resource
meow_iconTint	Icon color
meow_showBack	Show clear boxes text
meow_errorTextAppearance	Error textAppearance
meow_boxStyle	Styles: outlined or filled

Use it like this in XML Layout :

<meow.widget.MeowPinView
    android:id="@+id/pv"
    style="@style/Meow.PinView.Filled"
    app:meow_hint="@string/enter_code"
    app:meow_icon="@drawable/ic_dialpad" />

Learn more about it at fragment_form.xml.

Meow ProgressBar

There are some styles that is related to ProgressBar.

Style	Usage
Meow.ProgressBar.Small	Small ProgressBar
Meow.ProgressBar.Small.Primary	Small ProgressBar with primary color
Meow.ProgressBar.Small.PrimaryVariant	Small ProgressBar with PrimaryVariant color
Meow.ProgressBar.Small.PrimarySurface	Small ProgressBar with PrimarySurface color
Meow.ProgressBar.Small.Secondary	Small ProgressBar with secondary color
Meow.ProgressBar.Small.SecondaryVariant	Small ProgressBar with SecondaryVariant color
Meow.ProgressBar.Small.OnPrimary	Small ProgressBar with OnPrimary color
Meow.ProgressBar.Small.OnSecondary	Small ProgressBar with OnSecondary color
Meow.ProgressBar.Small.OnSurface	Small ProgressBar with OnSurface color
Meow.ProgressBar.Medium	Medium ProgressBar
Meow.ProgressBar.Medium.Primary	Medium ProgressBar with primary color
Meow.ProgressBar.Medium.PrimaryVariant	Medium ProgressBar with PrimaryVariant color
Meow.ProgressBar.Medium.PrimarySurface	Medium ProgressBar with PrimarySurface color
Meow.ProgressBar.Medium.Secondary	Medium ProgressBar with secondary color
Meow.ProgressBar.Medium.SecondaryVariant	Medium ProgressBar with SecondaryVariant color
Meow.ProgressBar.Medium.OnPrimary	Medium ProgressBar with OnPrimary color
Meow.ProgressBar.Medium.OnSecondary	Medium ProgressBar with OnSecondary color
Meow.ProgressBar.Medium.OnSurface	Medium ProgressBar with OnSurface color
Meow.ProgressBar.Large	Large ProgressBar
Meow.ProgressBar.Large.Primary	Large ProgressBar with primary color
Meow.ProgressBar.Large.PrimaryVariant	Large ProgressBar with PrimaryVariant color
Meow.ProgressBar.Large.PrimarySurface	Large ProgressBar with PrimarySurface color
Meow.ProgressBar.Large.Secondary	Large ProgressBar with secondary color
Meow.ProgressBar.Large.SecondaryVariant	Large ProgressBar with SecondaryVariant color
Meow.ProgressBar.Large.OnPrimary	Large ProgressBar with OnPrimary color
Meow.ProgressBar.Large.OnSecondary	Large ProgressBar with OnSecondary color
Meow.ProgressBar.Large.OnSurface	Large ProgressBar with OnSurface color

Meow ProgressBar Attributes:

Attributes	Descriptions
meow_showOnInit	Specify that the progress can be show on Initialization

Use it like this in XML Layout :

<meow.widget.MeowProgressBar
    style="@style/Meow.ProgressBar.Small.Primary"
    app:meow_showOnInit="true" />

Learn more about it at fragment_progress_bars.xml.

Meow Rating Bar

There are some styles that is related to RatingBar.

Style	Usage
Meow.RatingBar	RatingBar with default style
Meow.RatingBar.Indicator	RatingBar with enabled Indicator style (just show and not clickable)

Meow RatingBar Attributes:

Attributes	Descriptions
meow_numStars	The number of stars
meow_minimumStars	The minimum selected stars
meow_rating	Show while when use it
meow_starPadding	Stars padding
meow_drawableEmpty	Stars drawable when is empty
meow_drawableFilled	Stars drawable when is filled
meow_isIndicator	Specify that it is indicator or not
meow_scrollable	Specify that it is scrollable or not
meow_clickable	Specify that it is clickable or not
meow_clearRatingEnabled	Specify that clearRating is enabled or not
meow_starWidth	Stars Width
meow_starHeight	Stars Height
meow_stepSize	Step Size

Use it like this in XML Layout :

<meow.widget.MeowRatingBar
    style="@style/Meow.RatingBar" 
    app:meow_drawableEmpty="@drawable/ic_star"
    app:meow_drawableFilled="@drawable/ic_star_fill"
    app:meow_numStars="5"
    app:meow_stepSize="0.5" />

Learn more about it at fragment_rating_bars.xml.

Meow FormView (a cool widget😎)

With this widget, you no longer need to check the form fields (like editTexts and spinners) one by one.

Use it like this in XML Layout :

<meow.widget.MeowFormView
    android:id="@+id/fv"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    app:resetForm="true">
    
    <!-- You can add MeowTextField,MeowSpinner,Button and other views in this layout -->
    
</meow.widget.MeowFormView>

You can call validate() function to validate all widgets which are in MeowFormView as children :

binding.fv.validate {
    // When MeowFormView validate all widgets with their validate type, this line runs.
}

Learn more about it at fragment_form.xml.

Meow Spinner

There are some styles that is related to Spinner.

Style	Usage
Meow.Spinner.Outlined	Spinner with outlined style
Meow.Spinner.Outlined.Dense	Spinner with outlined dense style
Meow.Spinner.Filled	Spinner with Filled style
Meow.Spinner.Filled.Dense	Spinner with Filled dense style

If you want to use Validation Feature, you should add MeowSpinner to FormView Layout.

Attributes	Descriptions
meow_validateType	Types: empty,optional
meow_errorEmpty	Error empty Text (when spinner was empty you can show your customize error)

Use it like this in XML Layout :

<meow.widget.MeowSpinner
    style="@style/Meow.Spinner.Outlined"
    android:hint="@string/select"
    app:meow_validateType="empty" />

And for add Item in MeowSpinner : Supports : title , description and icon

 binding.spinner
    .addItem(R.string.item1, R.string.description1, R.drawable.ic_error)
    .addItem(R.string.item2, R.string.description2, R.drawable.ic_error)
    .addItem(R.string.item3, imageViewResId = R.drawable.ic_error)
    .addItem(R.string.item4, imageViewResId = R.drawable.ic_error)
    .addItem(R.string.item5, R.string.description3)
    .addItem(R.string.item6, R.string.description4)
    .addItem(R.string.item7)
    .addItem(R.string.item8)
    .build()

Learn more about it at Material Exposed Dropdown Menu Component and fragment_form.xml.

Meow TextField

There are some styles that is related to TextField.

Style	Usage
Meow.TextField.Outlined	TextField with outlined style
Meow.TextField.Outlined.Dense	TextField with outlined dense style
Meow.TextField.Filled	TextField with Filled style
Meow.TextField.Filled.Dense	TextField with Filled dense style

Meow TextField Attributes:

For use validation Feature you should add MeowTextField to FormView Layout.

If the error text is blank, the default message will be displayed.

Attributes	Descriptions
meow_validateType	Types: empty,mobile,mobileLegacy,email,optional
meow_errorEmpty	Error empty Text (when textfield was empty you can show your customize error)
meow_errorMobile	Error invalid mobile number
meow_errorMobileLegacy	Error invalid mobile legacy (persian) number
meow_errorEmail	Error invalid email
meow_textSize	TextField text size
meow_inputType	Default android TextInputLayout input type

Use it like this in XML Layout :

<meow.widget.MeowTextField
    style="@style/Meow.TextField.Filled"
    android:hint="@string/email"
    app:errorEnabled="true"
    app:meow_inputType="textEmailAddress"
    app:meow_validateType="email"
    app:startIconDrawable="@drawable/ic_android" />

Learn more about it at Material TextField Component and fragment_form.xml.

👮 ‍R8/Proguard

Just include rules of proguard-rules.pro at your application Proguard config file.

🖐 Contributing

If you want to contribute to this project, just send an email to oneHamidreza@gmail.com with Meow-Framework-Contributing subject.

License

Copyright 2020 Hamidreza Etebarian

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.