feat: add splash screen on example app

Add splash screen on example app.

Signed-off-by: Alex Manoel Ferreira Silva <alex@legytma.com.br>

example/android/app/src/main/AndroidManifest.xml

@@ -6,7 +6,6 @@
          additional functionality it is fine to subclass or reimplement
          FlutterApplication and put your custom class here. -->
     <application
-        android:name="io.flutter.app.FlutterApplication"
         android:label="schema_widget_sample"
         android:icon="@mipmap/ic_launcher">
         <activity
@@ -16,6 +15,18 @@
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
             android:hardwareAccelerated="true"
             android:windowSoftInputMode="adjustResize">
+            <!-- Specify that the launch screen should continue being displayed -->
+            <!-- until Flutter renders its first frame. -->
+            <meta-data
+                android:name="io.flutter.embedding.android.SplashScreenDrawable"
+                android:resource="@drawable/launch_background" />
+
+            <!-- Theme to apply as soon as Flutter begins rendering frames -->
+            <meta-data
+                android:name="io.flutter.embedding.android.NormalTheme"
+                android:resource="@style/NormalTheme"
+                />
+
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
                 <category android:name="android.intent.category.LAUNCHER"/>

example/android/app/src/main/res/drawable/launch_background.xml

@@ -4,9 +4,9 @@
     <item android:drawable="@android:color/white" />
 
     <!-- You can insert your own image assets here -->
-    <!-- <item>
+    <item>
         <bitmap
             android:gravity="center"
             android:src="@mipmap/launch_image" />
-    </item> -->
+    </item>
 </layer-list>

example/android/app/src/main/res/drawable/normal_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="@android:color/white" />
+
+    <!-- You can insert your own image assets here -->
+    <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item>
+</layer-list>

example/android/app/src/main/res/values/styles.xml

@@ -5,4 +5,7 @@
              Flutter draws its first frame -->
         <item name="android:windowBackground">@drawable/launch_background</item>
     </style>
+    <style name="NormalTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <item name="android:windowBackground">@drawable/normal_background</item>
+    </style>
 </resources>

lib/widget/schema_widget_splash_screen.dart

@@ -0,0 +1,108 @@
+// Copyright (c) 2020 Legytma Soluções Inteligentes (https://legytma.com.br).
+//
+//  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.
+
+import 'package:flutter/material.dart';
+import 'package:schema_widget/json_schema_resolver.dart';
+
+import '../schema_widget.dart';
+
+class SchemaWidgetSplashScreen extends StatefulWidget {
+  final Widget child;
+
+  const SchemaWidgetSplashScreen({Key key, this.child}) : super(key: key);
+
+  @override
+  _SchemaWidgetSplashScreenState createState() =>
+      _SchemaWidgetSplashScreenState();
+}
+
+class _SchemaWidgetSplashScreenState extends State<SchemaWidgetSplashScreen> {
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      mainAxisAlignment: MainAxisAlignment.center,
+      children: <Widget>[
+        Image(
+          image: AssetImage(
+            "assets/LegytmaSolucoesInteligentes.png",
+            package: "schema_widget",
+          ),
+        ),
+        StreamBuilder<FactoryStatistics>(
+          stream: SchemaWidget.factoryStream,
+          builder: (buildContext, snapshot) {
+            if (snapshot.hasData) {
+              var factoryStatistics = snapshot.data;
+
+              return Column(
+                mainAxisAlignment: MainAxisAlignment.center,
+                children: <Widget>[
+                  Text(
+                    factoryStatistics.toString(),
+                    style: TextStyle(
+                      fontSize: 7,
+                      color: Colors.black54,
+                    ),
+                  ),
+                  LinearProgressIndicator(
+                    value: factoryStatistics.value,
+                  ),
+                ],
+              );
+            }
+
+            return CircularProgressIndicator();
+          },
+        ),
+        StreamBuilder<JsonSchemaResolverStatistics>(
+          stream: SchemaWidget.jsonSchemaResolverStream,
+          builder: (buildContext, snapshot) {
+            if (snapshot.hasData) {
+              var jsonSchemaResolverStatistics = snapshot.data;
+
+              return Column(
+                mainAxisAlignment: MainAxisAlignment.center,
+                children: <Widget>[
+                  Text(
+                    jsonSchemaResolverStatistics.toString(),
+                    style: TextStyle(
+                      fontSize: 7,
+                      color: Colors.black54,
+                    ),
+                  ),
+                  LinearProgressIndicator(
+                    value: jsonSchemaResolverStatistics.requestValue,
+                  ),
+                ],
+              );
+            }
+
+            return CircularProgressIndicator();
+          },
+        ),
+        widget.child ??
+            StreamBuilder<FactoryStatistics>(
+              stream: SchemaWidget.factoryStream,
+              builder: (buildContext, snapshot) {
+                if (snapshot.hasError) {
+                  return Text('${snapshot.error}');
+                }
+
+                return Container();
+              },
+            ),
+      ],
+    );
+  }
+}