WaveApp Mobile Challenge

README.md

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-# Wave Software Development Challenge
-Applicants for the [Mobile engineer](https://wave.bamboohr.co.uk/jobs/view.php?id=6) role at Wave must complete the following challenge, and submit a solution prior to the onsite interview. 
+## Setup
+Download the apk from the root folder and install in your android device, by running the following command <code>adb install "waveapp-debug.apk"</code>
+Alternatively, The apk can be built from source using Android Studio (Requires Java 8, gradle)
+
+## Highlights
+1. Seperation of Concern with modular design (Decoupled with MVVM)
+2. Simple MVVM Pattern with Data Binding developed using TDD
+3. Android Lifecycle components
+4. Unit Test Infrastructure with unit tests for ViewModel and Adapter
+5. Retrofit library for network calls
+6. ViewModel implemented with Contract
+7. RecyclerView for scalable UI performance
 
-The purpose of this exercise is to create something that we can work on together during the onsite. We do this so that you get a chance to collaborate with Wavers during the interview in a situation where you know something better than us (it's your code, after all!) 
-
-There isn't a hard deadline for this exercise; take as long as you need to complete it. However, in terms of total time spent actively working on the challenge, we ask that you not spend more than a few hours, as we value your time and are happy to leave things open to discussion in the onsite interview.
-
-You can write your app using your favorite language, tools, platform, etc. Whether that means something native or something hybrid is completely up to you. 
-
-Send your submission to [dev.careers@waveapps.com](dev.careers@waveapps.com). Feel free to email [dev.careers@waveapps.com](dev.careers@waveapps.com) if you have any questions.
-
-## Submission Instructions
-1. Fork this project on github. You will need to create an account if you don't already have one.
-1. Complete the project as described below within your fork.
-1. Push all of your changes to your fork on github and submit a pull request. 
-1. You should also email [dev.careers@waveapps.com](dev.careers@waveapps.com) and your recruiter to let them know you have submitted a solution. Make sure to include your github username in your email (so we can match applicants with pull requests.)
-
-## Alternate Submission Instructions (if you don't want to publicize completing the challenge)
-1. Clone the repository.
-1. Complete your project as described below within your local repository.
-1. Email a patch file to [dev.careers@waveapps.com](dev.careers@waveapps.com).
-
-## Project Description
-In this project, we're going to be creating a simple app that shows a Wave user the products that they can charge for on their invoices. 
-
-You'll be using the public Wave API in this challenge. You can find the documentation [here](http://docs.waveapps.io/). You will specifically be interested in [the products endpoint](http://docs.waveapps.io/endpoints/products.html#get--businesses-business_id-products-), and [using an access token with the API](http://docs.waveapps.io/oauth/index.html#use-the-access-token-to-access-the-api). 
-
-Your Wave contact will supply you with a business ID and a Wave API token before you begin.
-
-### What your application must do:
-
-1. Your app must retrieve the list of products for the specific business ID sent to you by your Wave contact
-1. The list of products should be fetched and shown to the user in a list view when the app is launched.
-1. Each item in the list view should show the product name and price (formatted as a dollar amount.)
-
-You are not required to add any interactivity to the app -- i.e. you do not need to send the user to a detail view when they touch one of the list items. 
-
-Your app is allowed to render nothing if there is no internet connection when it loads.
-
-Once you're done, please submit a paragraph or two in your `README` about what you are particularly proud of in your implementation, and why.
-
-## Evaluation
-Evaluation of your submission will be based on the following criteria. 
-
-1. Did your application fulfill the basic requirements?
-1. Did you document the method for setting up and running your application?
-1. Did you follow the instructions for submission?

app/.gitignore

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+/build

app/build.gradle

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+plugins {
+    id 'com.android.application'
+}
+
+android {
+    compileSdkVersion 30
+    buildToolsVersion "30.0.3"
+    buildFeatures {
+        dataBinding true
+    }
+    defaultConfig {
+        applicationId "com.kannan.sample.waveapp"
+        minSdkVersion 21
+        targetSdkVersion 30
+        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
+    }
+
+}
+
+dependencies {
+    implementation 'android.arch.lifecycle:extensions:1.1.1'
+    implementation 'androidx.appcompat:appcompat:1.2.0'
+    implementation 'com.google.android.material:material:1.2.1'
+    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
+    implementation 'com.android.volley:volley:1.1.0'
+    implementation 'com.squareup.retrofit2:retrofit:2.0.0'
+    implementation 'com.squareup.retrofit2:converter-gson:2.2.0'
+    testImplementation 'junit:junit:4.+'
+    testImplementation "org.robolectric:robolectric:3.1"
+    testImplementation "org.mockito:mockito-core:1.10.19"
+    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
+}

app/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

app/src/androidTest/java/com/kannan/sample/waveapp/ExampleInstrumentedTest.java

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+package com.kannan.sample.waveapp;
+
+import android.content.Context;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.*;
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
+ */
+@RunWith(AndroidJUnit4.class)
+public class ExampleInstrumentedTest {
+    @Test
+    public void useAppContext() {
+        // Context of the app under test.
+        Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();
+        assertEquals("com.kannan.sample.waveapp", appContext.getPackageName());
+    }
+}

app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.kannan.sample.waveapp">
+
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.INTERNET" />
+
+    <application
+        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/Theme.WaveApp">
+        <activity android:name=".view.activity.HomeActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

app/src/main/java/com/kannan/sample/waveapp/api/ProductsAPI.java

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+package com.kannan.sample.waveapp.api;
+
+import com.kannan.sample.waveapp.model.Product;
+
+import java.util.List;
+
+import retrofit2.Call;
+import retrofit2.http.GET;
+import retrofit2.http.Headers;
+import retrofit2.http.Path;
+
+
+public interface ProductsAPI {
+    String ACCESS_TOKEN = "6W9hcvwRvyyZgPu9Odq7ko8DSY8Nfm";
+
+    /**
+     * Gets the list of products for the provided businessID
+     * @param businessID The business ID for which products need to be fetched
+     */
+    @Headers("Authorization: Bearer " + ACCESS_TOKEN)
+    @GET("businesses/{business_id}/products/")
+    Call<List<Product>> getProducts(@Path("business_id") String businessID);
+}

app/src/main/java/com/kannan/sample/waveapp/contract/ViewModelContract.java

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+package com.kannan.sample.waveapp.contract;
+
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.Observer;
+
+import com.kannan.sample.waveapp.model.Product;
+
+import java.util.List;
+
+public interface ViewModelContract {
+    void observe(LifecycleOwner lifecycleOwner, Observer<List<Product>> observer);
+    void getProducts(String BUSINESS_ID);
+}

app/src/main/java/com/kannan/sample/waveapp/facade/ProductsApiFacade.java

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+package com.kannan.sample.waveapp.facade;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.kannan.sample.waveapp.api.ProductsAPI;
+import com.kannan.sample.waveapp.model.Product;
+import java.util.List;
+import retrofit2.Callback;
+import retrofit2.Retrofit;
+import retrofit2.converter.gson.GsonConverterFactory;
+
+public class ProductsApiFacade {
+    private static final String BASE_URL = "https://api.waveapps.com/";
+    private Retrofit retrofit;
+
+    public ProductsApiFacade() {
+        Gson gson = new GsonBuilder()
+                .setLenient()
+                .create();
+        retrofit = new Retrofit.Builder()
+                .baseUrl(BASE_URL)
+                .addConverterFactory(GsonConverterFactory.create(gson))
+                .build();
+    }
+
+    public void getProducts(String businessID, Callback<List<Product>> callback) {
+        retrofit.create(ProductsAPI.class)
+                .getProducts(businessID)
+                .enqueue(callback);
+
+
+    }
+}

app/src/main/java/com/kannan/sample/waveapp/model/Product.java

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+package com.kannan.sample.waveapp.model;
+
+import androidx.databinding.BaseObservable;
+import androidx.databinding.Bindable;
+
+import java.text.NumberFormat;
+import java.util.Locale;
+
+public class Product extends BaseObservable {
+    private String name;
+    private int price;
+
+    public Product(String name, int price) {
+        this.name = name;
+        this.price = price;
+    }
+
+    @Bindable
+    public String getName() {
+        return name;
+    }
+
+    @Bindable
+    public String getPrice() {
+        return NumberFormat.getCurrencyInstance(Locale.getDefault()).format(price);
+    }
+
+}

app/src/main/java/com/kannan/sample/waveapp/util/ConnectionUtil.java

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+package com.kannan.sample.waveapp.util;
+
+import android.content.Context;
+import android.net.ConnectivityManager;
+
+public class ConnectionUtil {
+    public static boolean isConnectivityAvailable (Context context) {
+        ConnectivityManager connectivityManager = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE));
+        return connectivityManager != null && connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
+    }
+}

app/src/main/java/com/kannan/sample/waveapp/view/activity/HomeActivity.java

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+package com.kannan.sample.waveapp.view.activity;
+
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.lifecycle.ViewModelProviders;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+
+import android.os.Bundle;
+import android.view.View;
+import android.widget.ProgressBar;
+import android.widget.TextView;
+
+import com.kannan.sample.waveapp.R;
+import com.kannan.sample.waveapp.contract.ViewModelContract;
+import com.kannan.sample.waveapp.model.Product;
+import com.kannan.sample.waveapp.util.ConnectionUtil;
+import com.kannan.sample.waveapp.view.adapter.ProductsListAdapter;
+import com.kannan.sample.waveapp.viewmodel.ProductsViewModel;
+
+import java.util.List;
+
+public class HomeActivity extends AppCompatActivity {
+    private RecyclerView productsRecyclerView;
+    private ProgressBar progressBar;
+    private TextView errorTextView;
+    private ViewModelContract viewModel;
+    private static final String BUSINESS_ID = "89746d57-c25f-4cec-9c63-34d7780b044b";
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setupView();
+        initialize();
+    }
+
+    private void setupView (){
+        setContentView(R.layout.activity_home);
+        errorTextView = findViewById(R.id.tv_error);
+        productsRecyclerView = findViewById(R.id.rv_products_list);
+        progressBar = findViewById(R.id.pb_spinner);
+        productsRecyclerView.setAdapter(new ProductsListAdapter(this));
+        productsRecyclerView.setLayoutManager(new LinearLayoutManager(this));
+    }
+
+    private void initialize() {
+        viewModel = ViewModelProviders.of(this).get(ProductsViewModel.class);
+        viewModel.observe(this, products -> { updateView(products); });
+
+        if (ConnectionUtil.isConnectivityAvailable(this)) {
+            progressBar.setVisibility(View.VISIBLE);
+            viewModel.getProducts(BUSINESS_ID);
+        } else {
+            errorTextView.setText(R.string.no_connection);
+            errorTextView.setVisibility(View.VISIBLE);
+        }
+    }
+
+    private void updateView(List<Product> products) {
+        progressBar.setVisibility(View.GONE);
+        if (products == null) {
+            errorTextView.setText(R.string.api_failure);
+            errorTextView.setVisibility(View.VISIBLE);
+        } else {
+            errorTextView.setVisibility(View.GONE);
+            ((ProductsListAdapter) productsRecyclerView.getAdapter()).setItems(products);
+        }
+    }
+
+    @Override
+    protected void onDestroy() {
+        productsRecyclerView = null;
+        progressBar = null;
+        viewModel = null;
+        super.onDestroy();
+    }
+}