Add Android project for TFLite inference

android/.gitignore

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+*.iml
+.gradle
+/local.properties
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+
+/.gradle/
+/.idea/

android/app/.gitignore

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+/build
+/build/

android/app/build.gradle

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+apply plugin: 'com.android.application'
+apply plugin: 'de.undercouch.download'
+
+android {
+    compileSdkVersion 28
+    buildToolsVersion '28.0.3'
+    defaultConfig {
+        applicationId "org.tensorflow.lite.examples.detection"
+        minSdkVersion 21
+        targetSdkVersion 28
+        versionCode 1
+        versionName "1.0"
+
+        ndk {
+            abiFilters 'armeabi-v7a', 'arm64-v8a', 'x86'
+        }
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+    aaptOptions {
+        noCompress "tflite"
+    }
+    compileOptions {
+        sourceCompatibility = '1.8'
+        targetCompatibility = '1.8'
+    }
+    lintOptions {
+        abortOnError false
+    }
+}
+
+// import DownloadModels task
+project.ext.ASSET_DIR = projectDir.toString() + '/src/main/assets'
+project.ext.TMP_DIR = project.buildDir.toString() + '/downloads'
+
+// Download default models; if you wish to use your own models then
+// place them in the "assets" directory and comment out this line.
+//apply from: "download_model.gradle"
+
+//apply from: 'download_model.gradle'
+
+dependencies {
+//    implementation fileTree(dir: 'libs', include: ['*.jar', '*.aar'])
+//    implementation files('bin/gdbserver')
+    implementation 'androidx.appcompat:appcompat:1.1.0'
+    implementation 'androidx.coordinatorlayout:coordinatorlayout:1.1.0'
+    implementation 'com.google.android.material:material:1.1.0'
+    implementation 'org.tensorflow:tensorflow-lite:2.3.0'
+    implementation 'org.tensorflow:tensorflow-lite-gpu:2.3.0'
+//    implementation 'org.tensorflow:tensorflow-lite-select-tf-ops:2.3.0'
+//    implementation 'org.tensorflow:tensorflow-lite:2.2.0'
+//    implementation 'org.tensorflow:tensorflow-lite-gpu:2.2.0'
+//    implementation 'org.tensorflow:tensorflow-lite:1.14.0'
+//    implementation(name:'tensorflow-lite', ext:'aar')
+//    implementation(name:'tensorflow-lite-gpu', ext:'aar')
+
+//    implementation 'org.tensorflow:tensorflow-lite-gpu:1.14.0'
+//    implementation 'org.tensorflow:tensorflow-lite:0.0.0-gpu-experimental'
+    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+    implementation 'com.google.code.gson:gson:2.8.6'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
+    androidTestImplementation 'com.android.support.test:rules:1.0.2'
+    androidTestImplementation 'com.google.truth:truth:1.0.1'
+}

android/app/download_model.gradle

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+
+task downloadZipFile(type: Download) {
+    src 'http://storage.googleapis.com/download.tensorflow.org/models/tflite/coco_ssd_mobilenet_v1_1.0_quant_2018_06_29.zip'
+    dest new File(buildDir, 'zips/')
+    overwrite false
+}
+
+
+task downloadAndUnzipFile(dependsOn: downloadZipFile, type: Copy) {
+    from zipTree(downloadZipFile.dest)
+    into project.ext.ASSET_DIR
+}
+
+
+task extractModels(type: Copy) {
+    dependsOn downloadAndUnzipFile
+}
+
+tasks.whenTaskAdded { task ->
+    if (task.name == 'assembleDebug') {
+        task.dependsOn 'extractModels'
+    }
+    if (task.name == 'assembleRelease') {
+        task.dependsOn 'extractModels'
+    }
+}

android/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/app/src/androidTest/assets/table_results.txt

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+dining_table 27.492085 97.94615 623.1435 444.8627 0.48828125
+knife 342.53433 243.71082 583.89185 416.34595 0.4765625
+cup 68.025925 197.5857 202.02031 374.2206 0.4375
+book 185.43098 139.64153 244.51149 203.37737 0.3125

android/app/src/androidTest/java/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.tensorflow.lite.examples.detection">
+  <uses-sdk />
+</manifest>

android/app/src/androidTest/java/org/tensorflow/lite/examples/detection/DetectorTest.java

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+/*
+ * Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+ *
+ * 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.
+ */
+
+package org.tensorflow.lite.examples.detection;
+
+import static com.google.common.truth.Truth.assertThat;
+import static java.lang.Math.abs;
+import static java.lang.Math.max;
+import static java.lang.Math.min;
+
+import android.content.res.AssetManager;
+import android.graphics.Bitmap;
+import android.graphics.Bitmap.Config;
+import android.graphics.BitmapFactory;
+import android.graphics.Canvas;
+import android.graphics.Matrix;
+import android.graphics.RectF;
+import android.util.Size;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.platform.app.InstrumentationRegistry;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.tensorflow.lite.examples.detection.env.ImageUtils;
+import org.tensorflow.lite.examples.detection.tflite.Classifier;
+import org.tensorflow.lite.examples.detection.tflite.Classifier.Recognition;
+import org.tensorflow.lite.examples.detection.tflite.TFLiteObjectDetectionAPIModel;
+
+/** Golden test for Object Detection Reference app. */
+@RunWith(AndroidJUnit4.class)
+public class DetectorTest {
+
+  private static final int MODEL_INPUT_SIZE = 300;
+  private static final boolean IS_MODEL_QUANTIZED = true;
+  private static final String MODEL_FILE = "detect.tflite";
+  private static final String LABELS_FILE = "file:///android_asset/coco.txt";
+  private static final Size IMAGE_SIZE = new Size(640, 480);
+
+  private Classifier detector;
+  private Bitmap croppedBitmap;
+  private Matrix frameToCropTransform;
+  private Matrix cropToFrameTransform;
+
+  @Before
+  public void setUp() throws IOException {
+    AssetManager assetManager =
+        InstrumentationRegistry.getInstrumentation().getContext().getAssets();
+    detector =
+        TFLiteObjectDetectionAPIModel.create(
+            assetManager,
+            MODEL_FILE,
+            LABELS_FILE,
+            MODEL_INPUT_SIZE,
+            IS_MODEL_QUANTIZED);
+    int cropSize = MODEL_INPUT_SIZE;
+    int previewWidth = IMAGE_SIZE.getWidth();
+    int previewHeight = IMAGE_SIZE.getHeight();
+    int sensorOrientation = 0;
+    croppedBitmap = Bitmap.createBitmap(cropSize, cropSize, Config.ARGB_8888);
+
+    frameToCropTransform =
+        ImageUtils.getTransformationMatrix(
+            previewWidth, previewHeight,
+            cropSize, cropSize,
+            sensorOrientation, false);
+    cropToFrameTransform = new Matrix();
+    frameToCropTransform.invert(cropToFrameTransform);
+  }
+
+  @Test
+  public void detectionResultsShouldNotChange() throws Exception {
+    Canvas canvas = new Canvas(croppedBitmap);
+    canvas.drawBitmap(loadImage("table.jpg"), frameToCropTransform, null);
+    final List<Recognition> results = detector.recognizeImage(croppedBitmap);
+    final List<Recognition> expected = loadRecognitions("table_results.txt");
+
+    for (Recognition target : expected) {
+      // Find a matching result in results
+      boolean matched = false;
+      for (Recognition item : results) {
+        RectF bbox = new RectF();
+        cropToFrameTransform.mapRect(bbox, item.getLocation());
+        if (item.getTitle().equals(target.getTitle())
+            && matchBoundingBoxes(bbox, target.getLocation())
+            && matchConfidence(item.getConfidence(), target.getConfidence())) {
+          matched = true;
+          break;
+        }
+      }
+      assertThat(matched).isTrue();
+    }
+  }
+
+  // Confidence tolerance: absolute 1%
+  private static boolean matchConfidence(float a, float b) {
+    return abs(a - b) < 0.01;
+  }
+
+  // Bounding Box tolerance: overlapped area > 95% of each one
+  private static boolean matchBoundingBoxes(RectF a, RectF b) {
+    float areaA = a.width() * a.height();
+    float areaB = b.width() * b.height();
+    RectF overlapped =
+        new RectF(
+            max(a.left, b.left), max(a.top, b.top), min(a.right, b.right), min(a.bottom, b.bottom));
+    float overlappedArea = overlapped.width() * overlapped.height();
+    return overlappedArea > 0.95 * areaA && overlappedArea > 0.95 * areaB;
+  }
+
+  private static Bitmap loadImage(String fileName) throws Exception {
+    AssetManager assetManager =
+        InstrumentationRegistry.getInstrumentation().getContext().getAssets();
+    InputStream inputStream = assetManager.open(fileName);
+    return BitmapFactory.decodeStream(inputStream);
+  }
+
+  // The format of result:
+  // category bbox.left bbox.top bbox.right bbox.bottom confidence
+  // ...
+  // Example:
+  // Apple 99 25 30 75 80 0.99
+  // Banana 25 90 75 200 0.98
+  // ...
+  private static List<Recognition> loadRecognitions(String fileName) throws Exception {
+    AssetManager assetManager =
+        InstrumentationRegistry.getInstrumentation().getContext().getAssets();
+    InputStream inputStream = assetManager.open(fileName);
+    Scanner scanner = new Scanner(inputStream);
+    List<Recognition> result = new ArrayList<>();
+    while (scanner.hasNext()) {
+      String category = scanner.next();
+      category = category.replace('_', ' ');
+      if (!scanner.hasNextFloat()) {
+        break;
+      }
+      float left = scanner.nextFloat();
+      float top = scanner.nextFloat();
+      float right = scanner.nextFloat();
+      float bottom = scanner.nextFloat();
+      RectF boundingBox = new RectF(left, top, right, bottom);
+      float confidence = scanner.nextFloat();
+      Recognition recognition = new Recognition(null, category, confidence, boundingBox);
+      result.add(recognition);
+    }
+    return result;
+  }
+}

android/app/src/main/AndroidManifest.xml

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+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.tensorflow.lite.examples.detection">
+    <!-- Tell the system this app requires OpenGL ES 3.1. -->
+    <uses-feature android:glEsVersion="0x00030001" android:required="true" />
+
+    <uses-sdk />
+
+    <uses-permission android:name="android.permission.CAMERA" />
+
+    <uses-feature android:name="android.hardware.camera" />
+    <uses-feature android:name="android.hardware.camera.autofocus" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
+    <uses-permission android:name="android.permission.INTERNET"/>
+
+    <application
+        android:allowBackup="false"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/tfe_od_app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme.ObjectDetection"
+        android:hardwareAccelerated="true"
+        android:debuggable="true"
+        android:installLocation="internalOnly">
+
+        <activity
+            android:name=".DetectorActivity"
+            android:label="@string/tfe_od_app_name"
+            android:screenOrientation="portrait">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+
+    </application>
+</manifest>