安卓软件开发：使用机器学习TF框架和 CameraX 识别文本、识别语言和翻译文本

// CameraX 
def camerax_version = "1.0.0-beta05"
implementation "androidx.camera:camera-core:${camerax_version}"
implementation "androidx.camera:camera-camera2:${camerax_version}"
implementation "androidx.camera:camera-lifecycle:${camerax_version}"
implementation "androidx.camera:camera-view:1.0.0-alpha12"

// ML Kit
implementation 'com.google.android.gms:play-services-mlkit-text-recognition:16.0.0'
implementation 'com.google.mlkit:language-id:16.0.0'
implementation 'com.google.mlkit:translate:16.0.0'

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.google.mlkit.showcase.translate.main.MainFragment">

    <androidx.camera.view.PreviewView
        android:id="@+id/viewfinder"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintBottom_toTopOf="@id/middle"
        app:layout_constraintTop_toTopOf="parent" />
    <SurfaceView
        android:id="@+id/overlay"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintStart_toStartOf="@id/viewfinder"
        app:layout_constraintEnd_toEndOf="@id/viewfinder"
        app:layout_constraintBottom_toBottomOf="@id/viewfinder"
        app:layout_constraintTop_toTopOf="@id/viewfinder" />

    <androidx.constraintlayout.widget.Guideline
        android:id="@+id/middle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent=".5" />

    <TextView
        android:id="@+id/srcLang"
        style="@style/SrcLangText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="20dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="20dp"
        android:layout_marginBottom="4dp"
        app:layout_constraintBottom_toTopOf="@+id/srcTextScrollView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/middle"
        tools:text=">源语言" />

    <ScrollView
        android:id="@+id/srcTextScrollView"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:layout_marginBottom="4dp"
        android:fillViewport="true"
        android:scrollbars="vertical"
        app:layout_constraintBottom_toTopOf="@+id/divider"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/srcLang">

        <TextView
            android:id="@+id/srcText"
            style="@style/SrcText"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginStart="20dp"
            android:layout_marginEnd="20dp"
            tools:text="源文本" />
    </ScrollView>

    <View
        android:id="@+id/divider"
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginStart="20dp"
        android:layout_marginEnd="20dp"
        android:background="?android:attr/listDivider"
        app:layout_constraintBottom_toTopOf="@+id/targetLangSelector"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/srcTextScrollView" />

    <Spinner
        android:id="@+id/targetLangSelector"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="20dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/divider" />

    <ScrollView
        android:id="@+id/translatedTextScrollView"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:layout_marginBottom="4dp"
        android:fillViewport="true"
        android:scrollbars="vertical"
        app:layout_constraintBottom_toTopOf="@+id/divider2"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/targetLangSelector">

        <TextView
            android:id="@+id/translatedText"
            style="@style/TranslatedText"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginStart="20dp"
            android:layout_marginEnd="20dp"
            android:layout_marginBottom="4dp"
            tools:text="翻译文本" />
    </ScrollView>

    <View
        android:id="@+id/divider2"
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginStart="20dp"
        android:layout_marginTop="4dp"
        android:layout_marginEnd="20dp"
        android:layout_marginBottom="4dp"
        android:background="?android:attr/listDivider"
        app:layout_constraintBottom_toTopOf="@id/imageView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/translatedTextScrollView" />
        
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="20dp"
        android:scaleType="center"
        android:textSize="15sp"
        android:text="@Nim独立开发者"
        android:textColor="@color/colorAccent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/divider2" />
        
    <ProgressBar
        android:id="@+id/progressBar"
        style="?android:attr/progressBarStyle"
        android:layout_width="30dp"
        android:layout_height="30dp"
        android:visibility="invisible"
        app:layout_constraintStart_toEndOf="@+id/targetLangSelector"
        app:layout_constraintTop_toTopOf="@id/targetLangSelector"
        app:layout_constraintBottom_toBottomOf="@id/targetLangSelector" />

    <TextView
        android:id="@+id/progressText"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:text="@string/downloading_model_files"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/progressBar"
        app:layout_constraintBottom_toBottomOf="@id/progressBar"
        android:gravity="center_vertical"
        app:layout_constraintTop_toTopOf="@id/progressBar" />

</androidx.constraintlayout.widget.ConstraintLayout>

private val detector = TextRecognition.getClient(TextRecognizerOptions.DEFAULT_OPTIONS)

init {
   lifecycle.addObserver(detector)
}