Add Jetpack Glance sample (#20)

* Create glance sample app

* Add hello world, action handling, error ui, stateful and list widgets

* Add comments to the logic for reading the installed widgets info

* Add widgets size mode examples

* Center the content in the size mode examples

* Add remote views interop examples

* Update widgets metadata  + Add docs for the hello world and action widgets

* Add docs for remainder of widgets

* Update widgets preview images

* Update dependencies

* Add screenshots

* Create README.md

GlanceSample/.gitignore

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+*.iml
+.gradle
+/local.properties
+/.idea
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties

GlanceSample/README.md

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+# Glance - App widgets
+
+Android sample app to learn about the Jetpack Glance library, a recently introduced addition to Jetpack, built on top of compose that makes building app widgets easier.
+
+<img src="https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/screenshot/widgets-glance.png" alt="glance_widgets" height="1500">
+
+The app showcases:
+- Building a basic app widget ([HelloWorldWidget](https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/widget/HelloWorldWidget.kt))
+- Handling user interactions by firing a callback, or launching an Activity, Service or BroadcastReceiver ([ActionWidget](https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/widget/action/ActionWidget.kt)).
+- Handling widget errors and providing a custom error UI ([ErrorUIWidget](https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/widget/ErrorUIWidget.kt)).
+- Composing the widget's UI using the UI components Glance offers, and using GlanceModifier to decorate them and define their behavior ([ListWidget](https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/widget/ListWidget.kt)).
+- Building stateful app widgets, i.e storing the state of the widget's UI using a data store (e.g Preferences) and saving to it, as well as updating both the widget's state and refreshing its UI when the state changes ([StatefulWidget](https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/widget/StatefulWidget.kt)).
+- Choosing the right size mode to define how the widget's UI reacts to the user resizing it. Glance provides 3 options to choose from: Single, Exact and Responsive ([SizeSingleWidget](https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/widget/size/SizeSingleWidget.kt), [SizeExactWidget](https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/widget/size/SizeExactWidget.kt), [SizeResponsiveWidget](https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/widget/size/SizeResponsiveWidget.kt)).
+- Using Glance in interoperability with RemoteViews, the traditional way of building app widgets ([RemoteViewInteropWidget](https://github.com/husaynhakeem/android-playground/blob/master/GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/widget/interop/RemoteViewInteropWidget.kt)).

GlanceSample/app/.gitignore

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+/build

GlanceSample/app/build.gradle

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+plugins {
+    id 'com.android.application'
+    id 'kotlin-android'
+}
+
+android {
+    compileSdkVersion 31
+    defaultConfig {
+        applicationId "com.husaynhakeem.glancesample"
+        minSdkVersion 21
+        targetSdkVersion 31
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = '1.8'
+        useIR = true
+    }
+    buildFeatures {
+        compose true
+    }
+    composeOptions {
+        kotlinCompilerExtensionVersion compose_version
+        kotlinCompilerVersion kotlin_version
+    }
+}
+
+dependencies {
+    implementation 'androidx.core:core-ktx:1.7.0'
+    implementation 'androidx.appcompat:appcompat:1.4.1'
+    implementation 'com.google.android.material:material:1.5.0'
+    implementation "androidx.compose.ui:ui:$compose_version"
+    implementation "androidx.compose.material:material:$compose_version"
+    implementation "androidx.compose.ui:ui-tooling:$compose_version"
+    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.4.0'
+    implementation 'androidx.activity:activity-compose:1.4.0'
+    implementation "androidx.glance:glance-appwidget:1.0.0-alpha01"
+}

GlanceSample/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.husaynhakeem.glancesample">
+
+    <application
+        android:allowBackup="true"
+        android:label="@string/app_name"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.GlanceSample">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:label="@string/app_name"
+            android:theme="@style/Theme.GlanceSample.NoActionBar">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+
+        <activity android:name=".widget.action.DummyActivity" />
+
+        <service android:name=".widget.action.DummyService" />
+
+        <receiver android:name=".widget.action.DummyBroadcastReceiver" />
+
+        <!--Glance app widgets receivers-->
+        <receiver
+            android:name=".widget.HelloWorldWidgetReceiver"
+            android:enabled="true"
+            android:exported="false">
+
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_hello_world_info" />
+
+        </receiver>
+
+        <receiver
+            android:name=".widget.action.ActionWidgetReceiver"
+            android:enabled="true"
+            android:exported="false">
+
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_action_info" />
+
+        </receiver>
+
+        <receiver
+            android:name=".widget.ListWidgetReceiver"
+            android:enabled="true"
+            android:exported="false">
+
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_list_info" />
+
+        </receiver>
+
+        <receiver
+            android:name=".widget.ErrorUIWidgetReceiver"
+            android:enabled="true"
+            android:exported="false">
+
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_error_ui_info" />
+
+        </receiver>
+
+        <receiver
+            android:name=".widget.StatefulWidgetReceiver"
+            android:enabled="true"
+            android:exported="false">
+
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_stateful_info" />
+
+        </receiver>
+
+        <!--Widget.size-->
+        <receiver
+            android:name=".widget.size.SizeExactWidgetReceiver"
+            android:enabled="true"
+            android:exported="false">
+
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_size_exact_info" />
+
+        </receiver>
+
+        <receiver
+            android:name=".widget.size.SizeResponsiveWidgetReceiver"
+            android:enabled="true"
+            android:exported="false">
+
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_size_responsive_info" />
+
+        </receiver>
+
+        <receiver
+            android:name=".widget.size.SizeSingleWidgetReceiver"
+            android:enabled="true"
+            android:exported="false">
+
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_size_single_info" />
+
+        </receiver>
+
+        <!--Interop with remote views-->
+        <receiver
+            android:name=".widget.interop.RemoteViewWidgetProvider"
+            android:enabled="true"
+            android:exported="false" />
+
+        <receiver
+            android:name=".widget.interop.RemoteViewInteropWidgetReceiver"
+            android:enabled="true"
+            android:exported="false">
+
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_interop_info" />
+
+        </receiver>
+    </application>
+
+</manifest>

GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/MainActivity.kt

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+package com.husaynhakeem.glancesample
+
+import android.os.Bundle
+import androidx.activity.compose.setContent
+import androidx.activity.viewModels
+import androidx.appcompat.app.AppCompatActivity
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material.MaterialTheme
+import androidx.compose.material.Surface
+import androidx.compose.material.Text
+import androidx.compose.runtime.Composable
+import androidx.lifecycle.lifecycleScope
+import com.husaynhakeem.glancesample.ui.theme.GlanceSampleTheme
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+
+class MainActivity : AppCompatActivity() {
+
+    private val viewModel by viewModels<MainViewModel>()
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        viewModel
+            .widgets
+            .onEach { updateWidgets(it) }
+            .launchIn(lifecycleScope)
+    }
+
+    private fun updateWidgets(widgets: List<Widget>) {
+        setContent {
+            GlanceSampleTheme {
+                Surface(color = MaterialTheme.colors.background) {
+                    WidgetInfo(widgets = widgets)
+                }
+            }
+        }
+    }
+}
+
+@Composable
+fun WidgetInfo(widgets: List<Widget>) {
+    LazyColumn {
+        items(widgets) { widget ->
+            Text(text = widget.className)
+        }
+    }
+}

GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/MainViewModel.kt

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+package com.husaynhakeem.glancesample
+
+import android.app.Application
+import android.appwidget.AppWidgetManager
+import android.content.Context
+import androidx.compose.ui.unit.DpSize
+import androidx.glance.GlanceId
+import androidx.glance.appwidget.GlanceAppWidgetManager
+import androidx.glance.appwidget.GlanceAppWidgetReceiver
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+
+class MainViewModel(application: Application) : AndroidViewModel(application) {
+
+    private val _widgets = MutableStateFlow<List<Widget>>(emptyList())
+    val widgets = _widgets.asStateFlow()
+
+    init {
+        viewModelScope.launch {
+            _widgets.emit(getAppWidgets(application))
+        }
+    }
+
+    @Suppress("ConvertCallChainIntoSequence")
+    private suspend fun getAppWidgets(context: Context): List<Widget> {
+        val manager = GlanceAppWidgetManager(context)
+        return AppWidgetManager.getInstance(context)
+            // Get all the installed widget providers
+            .installedProviders
+            // Filter only this app's widgets providers
+            .filter { widgetProviderInfo -> widgetProviderInfo.provider.packageName == context.packageName }
+            // Get this app's widget provider classes
+            .mapNotNull { widgetProviderInfo -> Class.forName(widgetProviderInfo.provider.className) }
+            // Filter only glance widget providers
+            .filter { GlanceAppWidgetReceiver::class.java.isAssignableFrom(it) }
+            // Get each widget provider's widget
+            .map { (it.newInstance() as GlanceAppWidgetReceiver).glanceAppWidget.javaClass }
+            // Convert each widget to a UI model
+            .map {
+                val metadata = manager.getGlanceIds(it)
+                    .map { id ->
+                        WidgetMetadata(
+                            id = id,
+                            sizes = manager.getAppWidgetSizes(id),
+                        )
+                    }
+                Widget(
+                    className = it.simpleName,
+                    metadata = metadata,
+                )
+            }
+    }
+}
+
+data class Widget(
+    val className: String,
+    val metadata: List<WidgetMetadata>
+)
+
+data class WidgetMetadata(
+    val id: GlanceId,
+    val sizes: List<DpSize>
+)

GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/ui/theme/Color.kt

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+package com.husaynhakeem.glancesample.ui.theme
+
+import androidx.compose.ui.graphics.Color
+
+val Purple200 = Color(0xFFBB86FC)
+val Purple500 = Color(0xFF6200EE)
+val Purple700 = Color(0xFF3700B3)
+val Teal200 = Color(0xFF03DAC5)

GlanceSample/app/src/main/java/com/husaynhakeem/glancesample/ui/theme/Shape.kt

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+package com.husaynhakeem.glancesample.ui.theme
+
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.Shapes
+import androidx.compose.ui.unit.dp
+
+val Shapes = Shapes(
+    small = RoundedCornerShape(4.dp),
+    medium = RoundedCornerShape(4.dp),
+    large = RoundedCornerShape(0.dp)
+)