Android 如何创建Google Lens应用程序

从照片或视频流中提取和分析文本的能力是一个有价值的功能，可以极大地改善Android应用程序的功能和用户体验。Google Lens是由Google开发的一种先进的图像识别和增强现实技术，是这种能力的一个著名例子。虽然复制整个Google Lens的功能是一个困难的任务，但我们可以使用Google Vision API在Android应用程序中进行文本识别的简化实现。

使用的方法

在Android中使用Google Vision API进行文本识别

在Android中使用Google Vision API进行文本识别

步骤

步骤1 - 设置布局。

设计您的活动布局。创建一个包含用于相机预览的SurfaceView和用于显示识别文本的TextView的布局文件。
步骤2 - 创建活动。
创建一个新的活动类，让我们称之为GoogleLensActivity。
在onCreate()方法中，初始化相机并在SurfaceView上启动相机预览。
设置一个相机回调，在相机预览可用时捕获图像。

步骤3 - 显示识别的文本。
实现文本识别器的Processor接口以处理文本识别过程。
在TextRecognizer.Processor的receiveDetections()方法中，使用来自相机图像的识别文本更新识别文本的TextView。

步骤4 - 更新布局和清单。
更新布局XML文件以包括所需的视图（SurfaceView和TextView）。
将相机和互联网权限添加到应用的AndroidManifest.xml文件中。

XML代码

<!-- below line is use to add camera feature in our app -->
<uses-feature
android:name="android.hardware.camera"
android:required="true" />
<!-- permission for internet -->
<uses-permission android:name="android.permission.INTERNET" />

<meta-data
android:name="com.google.firebase.ml.vision.DEPENDENCIES"
android:value="label" />

XML代码

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.googlelens">

    <!-- below line is use to add camera feature in our app -->
    <uses-feature
        android:name="android.hardware.camera"
        android:required="true" />
    <!-- permission for internet -->
    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.GoogleLens">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <meta-data
            android:name="com.google.firebase.ml.vision.DEPENDENCIES"
            android:value="label" />

    </application>

</manifest>

XML代码

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
       xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <!--image view for displaying our image-->
    <ImageView
        android:id="@+id/image"
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="10dp"
        android:scaleType="centerCrop" />

    <LinearLayout
        android:id="@+id/idLLButtons"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/image"
        android:orientation="horizontal">

        <!--button for capturing our image-->
        <Button
            android:id="@+id/snapbtn"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="5dp"
            android:layout_marginTop="30dp"
            android:layout_weight="1"
            android:lines="2"
            android:text="Snap"
            android:textAllCaps="false"
            android:textSize="18sp"
            android:textStyle="bold" />

        <!--button for detecting the objects-->
        <Button
            android:id="@+id/idBtnSearchResuts"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="5dp"
            android:layout_marginTop="30dp"
            android:layout_weight="1"
            android:lines="2"
            android:text="Get Search Results"
            android:textAllCaps="false"
            android:textSize="18sp"
            android:textStyle="bold" />

    </LinearLayout>

    <!--recycler view for displaying the list of result-->
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/idRVSearchResults"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/idLLButtons" />

</RelativeLayout>

Java程序

import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.ml.vision.FirebaseVision;
import com.google.firebase.ml.vision.common.FirebaseVisionImage;
import com.google.firebase.ml.vision.label.FirebaseVisionImageLabel;
import com.google.firebase.ml.vision.label.FirebaseVisionImageLabeler;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    static final int REQUEST_IMAGE_CAPTURE = 1;

    // variables for our image view, image bitmap,
    // buttons, recycler view, adapter and array list.
    private ImageView img;
    private Button snap, searchResultsBtn;
    private Bitmap imageBitmap;
    private RecyclerView resultRV;
    private SearchResultsRVAdapter searchResultsRVAdapter;
    private ArrayList<DataModal> dataModalArrayList;
    private String title, link, displayed_link, snippet;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // initializing all our variables for views
        img = (ImageView) findViewById(R.id.image);
        snap = (Button) findViewById(R.id.snapbtn);
        searchResultsBtn = findViewById(R.id.idBtnSearchResuts);
        resultRV = findViewById(R.id.idRVSearchResults);

        // initializing our array list
        dataModalArrayList = new ArrayList<>();

        // initializing our adapter class.
        searchResultsRVAdapter = new SearchResultsRVAdapter(dataModalArrayList, MainActivity.this);

        // layout manager for our recycler view.
        LinearLayoutManager manager = new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);

        // on below line we are setting layout manager
        // and adapter to our recycler view.
        resultRV.setLayoutManager(manager);
        resultRV.setAdapter(searchResultsRVAdapter);

        // adding on click listener for our snap button.
        snap.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // calling a method to capture an image.
                dispatchTakePictureIntent();
            }
        });

        // adding on click listener for our button to search data.
        searchResultsBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // calling a method to get search results.
                getResults();
            }
        });
    }

    private void getResults() {
        // inside the label image method we are calling a firebase vision image
        // and passing our image bitmap to it.
        FirebaseVisionImage image = FirebaseVisionImage.fromBitmap(imageBitmap);

        // on below line we are creating a labeler for our image bitmap and
        // creating a variable for our firebase vision image labeler.
        FirebaseVisionImageLabeler labeler = FirebaseVision.getInstance().getOnDeviceImageLabeler();

        // calling a method to process an image and adding on success listener method to it.
        labeler.processImage(image).addOnSuccessListener(new OnSuccessListener<List<FirebaseVisionImageLabel>>() {
            @Override
            public void onSuccess(List<FirebaseVisionImageLabel> firebaseVisionImageLabels) {
                String searchQuery = firebaseVisionImageLabels.get(0).getText();
                searchData(searchQuery);
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                // displaying error message.
                Toast.makeText(MainActivity.this, "Fail to detect image..", Toast.LENGTH_SHORT).show();
            }
        });
    }

    private void searchData(String searchQuery) {
        String apiKey = "Enter your API key here";
        String url = "https://serpapi.com/search.json?q=" + searchQuery.trim() + "&location=Delhi,India&hl=en≷=us&google_domain=google.com&api_key=" + apiKey;

        // creating a new variable for our request queue
        RequestQueue queue = Volley.newRequestQueue(MainActivity.this);
        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                try {
                    // on below line we are extracting data from our json.
                    JSONArray organicResultsArray = response.getJSONArray("organic_results");
                    for (int i = 0; i < organicResultsArray.length(); i++) {
                        JSONObject organicObj = organicResultsArray.getJSONObject(i);
                        if (organicObj.has("title")) {
                            title = organicObj.getString("title");
                        }
                        if (organicObj.has("link")) {
                            link = organicObj.getString("link");
                        }
                        if (organicObj.has("displayed_link")) {
                            displayed_link = organicObj.getString("displayed_link");
                        }
                        if (organicObj.has("snippet")) {
                            snippet = organicObj.getString("snippet");
                        }
                        // on below line we are adding data to our array list.
                        dataModalArrayList.add(new DataModal(title, link, displayed_link, snippet));
                    }
                    // notifying our adapter class
                    // on data change in array list.
                    searchResultsRVAdapter.notifyDataSetChanged();
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                // displaying error message.
                Toast.makeText(MainActivity.this, "No Result found for the search query..", Toast.LENGTH_SHORT).show();
            }
        });
        // adding json object request to our queue.
        queue.add(jsonObjectRequest);
    }

    // method to capture image.
    private void dispatchTakePictureIntent() {
        // inside this method we are calling an implicit intent to capture an image.
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
            // calling a start activity for result when image is captured.
            startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // inside on activity result method we are
        // setting our image to our image view from bitmap.
        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
            Bundle extras = data.getExtras();
            imageBitmap = (Bitmap) extras.get("data");
            // on below line we are setting our
            // bitmap to our image view.
            img.setImageBitmap(imageBitmap);
        }
    }
}