Updated Android development HackPack with backend API integration

android-development/ic-hack-posts/.gitignore

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

android-development/ic-hack-posts/app/.gitignore

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+/build

android-development/ic-hack-posts/app/build.gradle.kts

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+plugins {
+    id("com.android.application")
+    id("org.jetbrains.kotlin.android")
+    id("org.jetbrains.kotlin.plugin.serialization") version "1.9.21"
+}
+
+android {
+    namespace = "com.example.ichackposts"
+    compileSdk = 34
+
+    defaultConfig {
+        applicationId = "com.example.ichackposts"
+        minSdk = 24
+        targetSdk = 34
+        versionCode = 1
+        versionName = "1.0"
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+        vectorDrawables {
+            useSupportLibrary = true
+        }
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+    buildFeatures {
+        compose = true
+    }
+    composeOptions {
+        kotlinCompilerExtensionVersion = "1.5.1"
+    }
+    packaging {
+        resources {
+            excludes += "/META-INF/{AL2.0,LGPL2.1}"
+        }
+    }
+}
+
+dependencies {
+
+    // Pin to versions compatible with compileSdk 34 and AGP 8.2.2
+    implementation("androidx.core:core-ktx:1.12.0")
+    implementation("androidx.lifecycle:lifecycle-runtime-ktx:2.6.2")
+    implementation("androidx.activity:activity-compose:1.8.2")
+    implementation(platform("androidx.compose:compose-bom:2023.10.01"))
+    implementation("androidx.compose.ui:ui")
+    implementation("androidx.compose.ui:ui-graphics")
+    implementation("androidx.compose.ui:ui-tooling-preview")
+    implementation("androidx.compose.material3:material3")
+    testImplementation("junit:junit:4.13.2")
+    androidTestImplementation("androidx.test.ext:junit:1.1.5")
+    androidTestImplementation("androidx.test.espresso:espresso-core:3.5.1")
+    androidTestImplementation(platform("androidx.compose:compose-bom:2023.10.01"))
+    androidTestImplementation("androidx.compose.ui:ui-test-junit4")
+    debugImplementation("androidx.compose.ui:ui-tooling")
+    debugImplementation("androidx.compose.ui:ui-test-manifest")
+
+    // Ktor Client
+    implementation("io.ktor:ktor-client-android:2.3.7")
+    implementation("io.ktor:ktor-client-content-negotiation:2.3.7")
+    implementation("io.ktor:ktor-serialization-kotlinx-json:2.3.7")
+
+    // Serialization (1.6.x is compatible with Kotlin 1.9.x)
+    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.6.3")
+}

android-development/ic-hack-posts/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

android-development/ic-hack-posts/app/src/androidTest/java/com/example/ichackposts/ExampleInstrumentedTest.kt

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+package com.example.ichackposts
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.example.ichackposts", appContext.packageName)
+    }
+}

android-development/ic-hack-posts/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"
+    xmlns:tools="http://schemas.android.com/tools">
+    <uses-permission android:name="android.permission.INTERNET" />
+    <application
+        android:allowBackup="true"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:fullBackupContent="@xml/backup_rules"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.ICHackPosts"
+        tools:targetApi="31">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:label="@string/app_name"
+            android:theme="@style/Theme.ICHackPosts">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

android-development/ic-hack-posts/app/src/main/java/com/example/ichackposts/MainActivity.kt

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+package com.example.ichackposts
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import com.example.ichackposts.ui.theme.ICHackPostsTheme
+import io.ktor.client.HttpClient
+import io.ktor.client.call.body
+import io.ktor.client.engine.android.Android
+import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.client.request.get
+import io.ktor.serialization.kotlinx.json.json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.Json
+
+@Serializable
+data class Post(
+    val id: Int,
+    val userId: Int,
+    val title: String,
+    val body: String
+)
+
+val client = HttpClient(Android) {
+    install(ContentNegotiation) {
+        json(Json {
+            ignoreUnknownKeys = true // Don't crash if the API adds new fields
+            prettyPrint = true
+        })
+    }
+}
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            ICHackPostsTheme {
+                // A surface container using the 'background' color from the theme
+                Surface(
+                    modifier = Modifier.fillMaxSize(),
+                    color = MaterialTheme.colorScheme.background
+                ) {
+                    PostsScreen()
+                }
+            }
+        }
+    }
+}
+
+@Composable
+fun PostsScreen(modifier: Modifier = Modifier) {
+    var posts by remember { mutableStateOf<List<Post>>(emptyList()) }
+    var isLoading by remember { mutableStateOf(true) }
+    var errorMessage by remember { mutableStateOf<String?>(null) }
+
+    // Fetch posts when the screen appears
+    LaunchedEffect(Unit) {
+        try {
+            posts = client.get("https://jsonplaceholder.typicode.com/posts").body()
+            isLoading = false
+        } catch (e: Exception) {
+            errorMessage = "Failed to load posts: ${e.message}"
+            isLoading = false
+        }
+    }
+
+    Box(
+        modifier = modifier.fillMaxSize(),
+        contentAlignment = Alignment.Center
+    ) {
+        when {
+            isLoading -> {
+                CircularProgressIndicator()
+            }
+            errorMessage != null -> {
+                Text(
+                    text = errorMessage!!,
+                    color = MaterialTheme.colorScheme.error,
+                    textAlign = TextAlign.Center,
+                    modifier = Modifier.padding(16.dp)
+                )
+            }
+            else -> {
+                PostsList(posts = posts)
+            }
+        }
+    }
+}
+
+@Composable
+fun PostsList(posts: List<Post>) {
+    LazyColumn(
+        contentPadding = PaddingValues(16.dp),
+        verticalArrangement = Arrangement.spacedBy(12.dp)
+    ) {
+        items(posts) { post ->
+            PostCard(post = post)
+        }
+    }
+}
+
+@Composable
+fun PostCard(post: Post) {
+    Card(
+        modifier = Modifier.fillMaxWidth(),
+        elevation = CardDefaults.cardElevation(defaultElevation = 2.dp)
+    ) {
+        Column(
+            modifier = Modifier.padding(16.dp)
+        ) {
+            Text(
+                text = post.title,
+                style = MaterialTheme.typography.titleMedium,
+                maxLines = 2,
+                overflow = TextOverflow.Ellipsis
+            )
+            Spacer(modifier = Modifier.height(8.dp))
+            Text(
+                text = post.body,
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 3,
+                overflow = TextOverflow.Ellipsis
+            )
+            Spacer(modifier = Modifier.height(8.dp))
+            Text(
+                text = "Post #${post.id} by User ${post.userId}",
+                style = MaterialTheme.typography.labelSmall,
+                color = MaterialTheme.colorScheme.outline
+            )
+        }
+    }
+}

android-development/ic-hack-posts/app/src/main/java/com/example/ichackposts/ui/theme/Color.kt

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+package com.example.ichackposts.ui.theme
+
+import androidx.compose.ui.graphics.Color
+
+val Purple80 = Color(0xFFD0BCFF)
+val PurpleGrey80 = Color(0xFFCCC2DC)
+val Pink80 = Color(0xFFEFB8C8)
+
+val Purple40 = Color(0xFF6650a4)
+val PurpleGrey40 = Color(0xFF625b71)
+val Pink40 = Color(0xFF7D5260)