Android 扫条形码后识别，连续拍照且实现照片预览

build.gradle文件库的引用：

implementation 'com.google.zxing:core:3.2.1'

识别条形码的activity：

public void onScanBarcode(View v){
    IntentIntegrator integrator = new IntentIntegrator(this);
    integrator.setDesiredBarcodeFormats(IntentIntegrator.ONE_D_CODE_TYPES);
    integrator.setPrompt("扫描条形码");
    integrator.setCameraId(0);
    integrator.setBeepEnabled(false);
    integrator.initiateScan();
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
    if(result != null) {
        if(result.getContents() == null) {
            Toast.makeText(this, "扫码取消！", Toast.LENGTH_LONG).show();
        } else {
            final String stuno = result.getContents();
            new Thread(){
                @Override
                public void run() {
                    getUserName(stuno);
                }
            }.start();
            Toast.makeText(this, "扫描成功，条码值:" + result.getContents(), Toast.LENGTH_LONG).show();


        }
    } else {
        super.onActivityResult(requestCode, resultCode, data);
    }
}

result.getContents()得到的是一个数字，即扫描条形码得出的结果

拍照的activity

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.v4.content.FileProvider;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;
import com.example.ceo.identifyapp.util.UpLoadFileToSerUtil;
import com.example.ceo.identifyapp.util.UrlUtil;
import java.io.File;
import java.io.IOException;

public class GetPictureActivity extends AppCompatActivity {

    private final int TAKE_PHOTO = 1;//拍照操作
    /*
     *  拍照所得到的图像的保存路径
     */
    private Uri imageUri;
    private String image;
    private int i=0;

    //相机请求码
    private static final int REQUESTCODE_CAMERA = 1002;
    private ImageView picture1;
    private ImageView picture2;
    private ImageView picture3;
    private Button takephoto;
    private Button complete;
    int j=1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_get_picture);
        complete=(Button)findViewById(R.id.BUTTON_COMPLETE);
        takephoto=(Button)findViewById(R.id.BUTTON_TAKE_PHOTO);
        picture1=(ImageView)findViewById(R.id.picture1);
        picture2=(ImageView)findViewById(R.id.picture2);
        picture3=(ImageView)findViewById(R.id.picture3);
        complete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent();
                intent.setClass(GetPictureActivity.this,MainActivity.class);
                startActivity(intent);
                finish();
            }
        });


        takephoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                takePhoto();
            }
        });


    }


    public void takePhoto(){
        /*
         *  当前用户拍照或者从相册选择的照片的文件名
         */
        String stuname= getIntent().getStringExtra("stuname");
        String stuid= getIntent().getStringExtra("stuid");
        String fileName=stuid+"-"+stuname;
        File outputImage;
        if (new File(UrlUtil.IMAGES_UPLOAD+fileName+"-"+(i+1)+".png").exists()){
            while (new File(UrlUtil.IMAGES_UPLOAD+fileName+"-"+(i+1)+".png").exists()){
                i++;
            }
            outputImage=new File(UrlUtil.IMAGES_UPLOAD+fileName+"-"+(i+1)+".png");
            try {
                outputImage.createNewFile();
            }catch (IOException e){
                e.printStackTrace();
            }
            Uri contentUri = FileProvider.getUriForFile(this, "com.example.ceo.identifyapp.fileprovider", outputImage);
            image=outputImage.toString();
            /*
             *  启动系统的照相Intent
             */
            Intent intent=new Intent("android.media.action.IMAGE_CAPTURE");
            intent.putExtra(MediaStore.EXTRA_OUTPUT,contentUri);
            startActivityForResult(intent,TAKE_PHOTO);

        }else {
            outputImage=new File(UrlUtil.IMAGES_UPLOAD+fileName+"-"+(i+1)+".png");//照片名字取名为特定人名字加第几张
            try {
                outputImage.createNewFile();
            }catch (IOException e){
                e.printStackTrace();
            }
            Uri contentUri = FileProvider.getUriForFile(this, "com.example.ceo.identifyapp.fileprovider", outputImage);//因为新版本的安卓需要靠fileprovider去临时赋予权限，不然会报错
            image=outputImage.toString();
            Intent intent=new Intent("android.media.action.IMAGE_CAPTURE");
            intent.putExtra(MediaStore.EXTRA_OUTPUT,contentUri);
            startActivityForResult(intent,TAKE_PHOTO);
        }
    }
    /**
     * 因为启动拍照intent的时候是使用的forResult模式，因此需要onActivityResult方法来接受回调参数
     * @param requestCode
     * @param resultCode
     * @param data
     */
    @Override
    protected void onActivityResult(int requestCode,int resultCode,Intent data){
        super.onActivityResult(requestCode,resultCode,data);
        String stuname= getIntent().getStringExtra("stuname");
        String stuid= getIntent().getStringExtra("stuid");
        String fileName=stuid+"-"+stuname;
        if (resultCode != RESULT_OK) {
            Toast.makeText(this, "获取图片出现错误", Toast.LENGTH_SHORT).show();
        }
        else{
            switch(requestCode) {
                /*
                 *  case TAKE_PHOTO 代表从拍摄照片的intent返回之后
                 *  完成拍摄照片之后，立刻打开系统自带的裁剪图片的intent
                 */
                case TAKE_PHOTO:
                    try {
                        new Thread(){
                            @Override
                            public void run() {
                                UpLoadFileToSerUtil.uploadFile(new File(image),UrlUtil.IMAGES_UPLOAD_URL);
                            }
                        }.start();
                    }catch (Exception e){
                        e.printStackTrace();
                    }

                    Bitmap bitmap = BitmapFactory.decodeFile(image);
                    if (j==1){picture1.setImageBitmap(bitmap);
                    }else if (j==2){
                        picture2.setImageBitmap(bitmap);
                    }else if (j==3){
                        picture3.setImageBitmap(bitmap);
                        break;//第三张照片的时候不再拍照
                    }
                    takephoto.setVisibility(View.GONE);
                    j++;
                    takePhoto();
                    Toast.makeText(this,"图片保存成功！", Toast.LENGTH_SHORT).show();

                default:
                    break;
            }
        }

    }
}