[app] Introduce MainActivity

A class responsible for showing a list of use cases
covered in the app.
This commit also adds some UI libraries to be used
in the app.

app/build.gradle

@@ -48,6 +48,10 @@ android {
 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
     compile "com.android.support:support-v4:${versions.libs.support}"
+    compile "com.android.support:appcompat-v7:${versions.libs.support}"
+    compile "com.android.support:recyclerview-v7:${versions.libs.support}"
+    compile 'com.jakewharton:butterknife:8.4.0'
+    annotationProcessor 'com.jakewharton:butterknife-compiler:8.4.0'
     compile('ch.acra:acra:4.9.0') {
         exclude group: 'org.json'
     }

app/src/main/AndroidManifest.xml

@@ -1,4 +1,5 @@
-<?xml version="1.0" encoding="utf-8"?><!--
+<?xml version="1.0" encoding="utf-8"?>
+<!--
   ~ Copyright 2014 serso aka se.solovyev
   ~
   ~ Licensed under the Apache License, Version 2.0 (the "License");
@@ -39,6 +40,15 @@
         android:icon="@drawable/ic_launcher"
         android:label="@string/app_name"
         android:supportsRtl="true"
-        tools:ignore="GoogleAppIndexingWarning" />
+        android:theme="@style/Theme.AppCompat.Light.DarkActionBar"
+        tools:ignore="GoogleAppIndexingWarning">
+        <activity android:name=".MainActivity">
+            <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/org/solovyev/android/checkout/app/MainActivity.java

@@ -0,0 +1,115 @@
+package org.solovyev.android.checkout.app;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.support.annotation.StringRes;
+import android.support.v7.app.AppCompatActivity;
+import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import butterknife.BindView;
+import butterknife.ButterKnife;
+
+/**
+ * Shows a list of use cases covered in the app.
+ */
+public class MainActivity extends AppCompatActivity {
+
+    @BindView(R.id.recycler)
+    RecyclerView mRecycler;
+
+    @Override
+    protected void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+        ButterKnife.bind(this);
+
+        mRecycler.setLayoutManager(new LinearLayoutManager(this));
+        mRecycler.setAdapter(new Adapter(this));
+    }
+
+    private enum UseCase {
+        ;
+
+        // activity to be started on click
+        final Class<? extends Activity> activity;
+        @StringRes
+        final int title;
+        @StringRes
+        final int description;
+
+        UseCase(Class<? extends Activity> activity, @StringRes int title, @StringRes int description) {
+            this.activity = activity;
+            this.title = title;
+            this.description = description;
+        }
+    }
+
+    static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
+
+        private final Activity mActivity;
+        @BindView(R.id.use_case_title)
+        TextView mTitle;
+        @BindView(R.id.use_case_description)
+        TextView mDescription;
+        @Nullable
+        private UseCase mUseCase;
+
+
+        ViewHolder(Activity activity, View view) {
+            super(view);
+            mActivity = activity;
+            ButterKnife.bind(this, view);
+
+            view.setOnClickListener(this);
+        }
+
+        void onBind(UseCase useCase) {
+            mUseCase = useCase;
+            mTitle.setText(useCase.title);
+            mDescription.setText(useCase.description);
+        }
+
+        @Override
+        public void onClick(View v) {
+            if (mUseCase == null) {
+                return;
+            }
+            mActivity.startActivity(new Intent(mActivity, mUseCase.activity));
+        }
+    }
+
+    private static class Adapter extends RecyclerView.Adapter<ViewHolder> {
+
+        private final Activity mActivity;
+        private final UseCase[] mUseCases = UseCase.values();
+        private final LayoutInflater mInflater;
+
+        private Adapter(Activity activity) {
+            mActivity = activity;
+            mInflater = LayoutInflater.from(activity);
+        }
+
+        @Override
+        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+            final View view = mInflater.inflate(R.layout.use_case, parent, false);
+            return new ViewHolder(mActivity, view);
+        }
+
+        @Override
+        public void onBindViewHolder(ViewHolder holder, int position) {
+            holder.onBind(mUseCases[position]);
+        }
+
+        @Override
+        public int getItemCount() {
+            return mUseCases.length;
+        }
+    }
+}

app/src/main/res/layout/activity_main.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/recycler"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" />

app/src/main/res/layout/use_case.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:background="?selectableItemBackground"
+    android:gravity="center_vertical"
+    android:minHeight="?listPreferredItemHeightLarge"
+    android:orientation="vertical"
+    android:paddingEnd="?listPreferredItemPaddingRight"
+    android:paddingLeft="?listPreferredItemPaddingLeft"
+    android:paddingRight="?listPreferredItemPaddingRight"
+    android:paddingStart="?listPreferredItemPaddingLeft">
+
+    <TextView
+        android:id="@+id/use_case_title"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:textAppearance="?textAppearanceListItem" />
+
+    <TextView
+        android:id="@+id/use_case_description"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:textAppearance="?textAppearanceListItem"
+        android:textColor="@android:color/tertiary_text_light"
+        android:textSize="14sp" />
+
+</LinearLayout>