引用公共库:builder.radle，在app目录下

implementation 'com.google.android.gms:play-services-maps:17.0.0'implementation 'com.google.android.gms:play-services-vision:19.0.0'implementation 'com.google.android.gms:auth-api-impl:11.6.0'

3.清单文件，拍照权限申请

4.主界面：

package com.example.administrator.testz;  import android.Manifest;import android.app.Activity;import android.content.ActivityNotFoundException;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.content.pm.PackageManager;import android.content.res.Resources;import android.net.Uri;import android.os.Bundle;import android.os.PersistableBundle;import android.os.Vibrator;import android.util.Log;import android.util.SparseArray;import android.view.SurfaceHolder;import android.view.SurfaceView;import android.widget.TextView; import com.google.android.gms.vision.CameraSource;import com.google.android.gms.vision.Detector;import com.google.android.gms.vision.barcode.Barcode;import com.google.android.gms.vision.barcode.BarcodeDetector; import java.io.IOException;import java.util.ArrayList; import androidx.annotation.Nullable;import androidx.appcompat.app.AppCompatActivity;import androidx.core.app.ActivityCompat;  public class MainActivity extends AppCompatActivity {  SurfaceView surfaceView; CameraSource cameraSource; TextView qrCodeText; BarcodeDetector barcodeDetector; public static ArrayList scannList;  @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); surfaceView = (SurfaceView) findViewById(R.id.qrView); qrCodeText = (TextView) findViewById(R.id.tv); scannList = new ArrayList<>(); barcodeDetector = new BarcodeDetector.Builder(this)  .setBarcodeFormats(Barcode.QR_CODE)  .build(); cameraSource = new CameraSource.Builder(this, barcodeDetector)  .setRequestedPreviewSize(640, 480)  .setAutoFocusEnabled(true)  .build(); surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {  @Override  public void surfaceCreated(SurfaceHolder holder) {  if (ActivityCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {   return;  }  try {   cameraSource.start(holder);  } catch (IOException e) {   e.printStackTrace();  }  }   @Override  public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {   }   @Override  public void surfaceDestroyed(SurfaceHolder holder) {  cameraSource.stop();  } });   barcodeDetector.setProcessor(new Detector.Processor() {  @Override  public void release() {  }   @Override  public void receiveDetections(Detector.Detections detections) {  final SparseArray qrCode = detections.getDetectedItems();   if (qrCode.size() != 0) {   qrCodeText.post(new Runnable() {   @Override   public void run() {    qrCodeText.setText(qrCode.valueAt(0).displayValue);    addInList(qrCode.valueAt(0).displayValue);   }   });  }  } });  }  private void addInList(String scannResult) { if (scannList.isEmpty()) {  scannList.add(scannResult); } else {  String a = scannList.get(scannList.size() - 1);  if (!a.equals(scannResult)) {  scannList.add(scannResult);  } } for (String s : scannList) {  Log.e("s", "onCreate: " + s); } Log.e("size", "addInList: " + scannList.size());  }  @Override protected void onDestroy() { super.onDestroy();  }}

5.布局页面：