Convert sample to compose

Various improvements.

1. Compose to be up to date with android standards.
2. Kotlin since Java is no longer the programming language for Android.
3. Coroutines instead of threads for better multithreaded management.
4. Flows instead of LiveData
5. Document the code somewhat.

Author: Doomsdayrs

build.gradle.kts

@@ -8,6 +8,7 @@ buildscript {
 	}
 	dependencies {
 		classpath(libs.gradle)
+		classpath(libs.kotlin.gradle.plugin)
 
 		// NOTE: Do not place your application dependencies here; they belong
 		// in the individual module build.gradle files

gradle/libs.versions.toml

@@ -16,6 +16,12 @@ test = "1.6.1"
 tesseract4android = "4.7.0"
 coreKtx = "1.13.1"
 kotlin = "2.0.0"
+kotlinGradlePlugin = "1.9.0"
+lifecycleRuntimeKtx = "2.8.3"
+activityCompose = "1.9.0"
+composeBom = "2024.06.00"
+window = "1.3.0"
+adaptiveAndroid = "1.0.0-beta04"
 
 [libraries]
 androidx-annotation = { module = "androidx.annotation:annotation", version.ref = "annotation" }
@@ -25,8 +31,10 @@ androidx-espresso-core = { module = "androidx.test.espresso:espresso-core", vers
 androidx-junit = { module = "androidx.test.ext:junit", version.ref = "androidJUnit" }
 androidx-lifecycle-livedata = { module = "androidx.lifecycle:lifecycle-livedata", version.ref = "lifecycleLivedata" }
 androidx-lifecycle-viewmodel = { module = "androidx.lifecycle:lifecycle-viewmodel", version.ref = "lifecycleLivedata" }
+androidx-lifecycle-viewmodel-compose = { module = "androidx.lifecycle:lifecycle-viewmodel-compose" }
 androidx-rules = { module = "androidx.test:rules", version.ref = "test" }
 androidx-runner = { module = "androidx.test:runner", version.ref = "test" }
+androidx-window = { module = "androidx.window:window", version.ref = "window" }
 gradle = { module = "com.android.tools.build:gradle", version.ref = "gradle" }
 junit = { module = "junit:junit", version.ref = "junit" }
 material = { module = "com.google.android.material:material", version.ref = "material" }
@@ -38,6 +46,18 @@ tesseract4android-jitpack-openmp = { group = "cz.adaptech.tesseract4android", na
 tesseract4android-local = { group = "cz.adaptech", name = "tesseract4android", version.ref = "tesseract4android" }
 tesseract4android-local-openmp = { group = "cz.adaptech", name = "tesseract4android-openmp", version.ref = "tesseract4android" }
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
+kotlin-gradle-plugin = { group = "org.jetbrains.kotlin", name = "kotlin-gradle-plugin", version.ref = "kotlinGradlePlugin" }
+androidx-lifecycle-runtime-ktx = { group = "androidx.lifecycle", name = "lifecycle-runtime-ktx", version.ref = "lifecycleRuntimeKtx" }
+androidx-activity-compose = { group = "androidx.activity", name = "activity-compose", version.ref = "activityCompose" }
+androidx-compose-bom = { group = "androidx.compose", name = "compose-bom", version.ref = "composeBom" }
+androidx-ui = { group = "androidx.compose.ui", name = "ui" }
+androidx-ui-graphics = { group = "androidx.compose.ui", name = "ui-graphics" }
+androidx-ui-tooling = { group = "androidx.compose.ui", name = "ui-tooling" }
+androidx-ui-tooling-preview = { group = "androidx.compose.ui", name = "ui-tooling-preview" }
+androidx-ui-test-manifest = { group = "androidx.compose.ui", name = "ui-test-manifest" }
+androidx-ui-test-junit4 = { group = "androidx.compose.ui", name = "ui-test-junit4" }
+androidx-material3 = { group = "androidx.compose.material3", name = "material3" }
+androidx-adaptive-android = { group = "androidx.compose.material3.adaptive", name = "adaptive-android", version.ref = "adaptiveAndroid" }
 
 [plugins]
-jetbrains-kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
+jetbrains-kotlin-android = { id = "org.jetbrains.kotlin.android" }

sample/build.gradle.kts

@@ -15,11 +15,13 @@ android {
 		versionName = "1.0"
 
 		testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+		vectorDrawables {
+			useSupportLibrary = true
+		}
 	}
 
 	buildTypes {
 		release {
-			isMinifyEnabled = false
 			proguardFiles(
 				getDefaultProguardFile("proguard-android-optimize.txt"),
 				"proguard-rules.pro"
@@ -32,10 +34,19 @@ android {
 	}
 	buildFeatures {
 		viewBinding = true
+		compose = true
 	}
 	kotlinOptions {
 		jvmTarget = "17"
 	}
+	composeOptions {
+		kotlinCompilerExtensionVersion = "1.5.1"
+	}
+	packaging {
+		resources {
+			excludes += "/META-INF/{AL2.0,LGPL2.1}"
+		}
+	}
 }
 
 // In case you are using dependency on local library (the project(":tesseract4android") below),
@@ -64,13 +75,26 @@ dependencies {
 	// Which flavor to use is determined by missingDimensionStrategy parameter above.
 	//implementation(project(":tesseract4android"))
 
-	implementation(libs.androidx.appcompat)
 	implementation(libs.material)
-	implementation(libs.androidx.constraintlayout)
-	implementation(libs.androidx.lifecycle.livedata)
-	implementation(libs.androidx.lifecycle.viewmodel)
 	implementation(libs.androidx.core.ktx)
+	implementation(libs.androidx.activity.compose)
+	implementation(platform(libs.androidx.compose.bom))
+	implementation(libs.androidx.ui)
+	implementation(libs.androidx.ui.graphics)
+	implementation(libs.androidx.ui.tooling.preview)
+	implementation(libs.androidx.material3)
+	implementation(libs.androidx.window)
+
+	implementation(libs.androidx.lifecycle.runtime.ktx)
+	implementation(libs.androidx.lifecycle.viewmodel)
+	implementation(libs.androidx.lifecycle.viewmodel.compose)
+	implementation(libs.androidx.adaptive.android)
+
 	testImplementation(libs.junit)
 	androidTestImplementation(libs.androidx.junit)
 	androidTestImplementation(libs.androidx.espresso.core)
+	androidTestImplementation(platform(libs.androidx.compose.bom))
+	androidTestImplementation(libs.androidx.ui.test.junit4)
+	debugImplementation(libs.androidx.ui.tooling)
+	debugImplementation(libs.androidx.ui.test.manifest)
 }

sample/src/androidTest/java/cz/adaptech/tesseract4android/sample/ExampleInstrumentedTest.java

@@ -1,17 +1,23 @@
 package cz.adaptech.tesseract4android.sample
 
 import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.enableEdgeToEdge
 import androidx.appcompat.app.AppCompatActivity
-import cz.adaptech.tesseract4android.sample.ui.main.MainFragment
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Scaffold
+import androidx.compose.ui.Modifier
+import cz.adaptech.tesseract4android.sample.ui.main.MainView
+import cz.adaptech.tesseract4android.sample.ui.theme.Tesseract4AndroidTheme
 
-class MainActivity : AppCompatActivity() {
+class MainActivity : ComponentActivity() {
 	override fun onCreate(savedInstanceState: Bundle?) {
 		super.onCreate(savedInstanceState)
-		setContentView(R.layout.activity_main)
-		if (savedInstanceState == null) {
-			supportFragmentManager.beginTransaction()
-				.replace(R.id.container, MainFragment.newInstance())
-				.commitNow()
+		enableEdgeToEdge()
+		setContent {
+			MainView()
 		}
 	}
 }

sample/src/main/java/cz/adaptech/tesseract4android/sample/MainActivity.kt

@@ -0,0 +1,52 @@
+package cz.adaptech.tesseract4android.sample
+
+
+/**
+ * Represents the various states that the OCR can be in.
+ *
+ * @since 2024/07/22
+ * @author Clocks
+ */
+sealed interface OCRState {
+	/**
+	 * OCR is loading up.
+	 */
+	data object Loading : OCRState
+
+	/**
+	 * OCR is prepared.
+	 *
+	 * @param version Version of tesseract
+	 * @param flavour Build flavour of tesseract
+	 */
+	data class StartUp(val version: String, val flavour: String) : OCRState
+
+	/**
+	 * OCR has been stopped.
+	 */
+	data object Stopped : OCRState
+
+	/**
+	 * OCR is being stopped.
+	 */
+	data object Stopping : OCRState
+
+	/**
+	 * OCR is starting up.
+	 */
+	data object Processing : OCRState
+
+	/**
+	 * OCR is currently in process.
+	 *
+	 * @param progress 0-100 progress indication.
+	 */
+	data class Progress(val progress: Int) : OCRState
+
+	/**
+	 * OCR has completed its task.
+	 *
+	 * @param time How many seconds it took to process the image.
+	 */
+	data class Finished(val time: Float) : OCRState
+}