Android中二维码的扫描和生成(使用zxing库)

    <!--摄像机权限-->
    <uses-permission android:name="android.permission.CAMERA" />
    <!--手机震动权限-->
    <uses-permission android:name="android.permission.VIBRATE" />
    <!--读取本地图片权限-->
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

<com.google.android.material.appbar.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">
 
    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />
 
</com.google.android.material.appbar.AppBarLayout>
 
<include layout="@layout/content_main" />
 
<com.google.android.material.floatingactionbutton.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    app:srcCompat="@android:drawable/ic_dialog_email" />

<TextView
    android:id="@+id/myTextView"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginTop="48dp"
    android:hint="扫描结果"
    android:textSize="24sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/myScanButton"
    app:layout_constraintVertical_bias="0.0" />
 
<EditText
    android:id="@+id/myEditText"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginTop="16dp"
    android:ems="10"
    android:hint="输入要生成二维码的字符"
    android:inputType="textPersonName"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />
 
<Button
    android:id="@+id/myCreateButton"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:text="开始生成"
    android:textSize="18sp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/myEditText" />
 
<ImageView
    android:id="@+id/myImageView"
    android:layout_width="202dp"
    android:layout_height="196dp"
    android:layout_marginTop="64dp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.497"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/myCreateButton"
    app:srcCompat="@android:drawable/screen_background_light_transparent" />
 
<Button
    android:id="@+id/myScanButton"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginTop="36dp"
    android:text="开始扫描"
    android:textSize="18sp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/myImageView" />

public class CreateUtil {
    //String codestring：要生成二维码的字符串
    // int width：二维码图片的宽度
    // int height：二维码图片的高度
    public static Bitmap createQRCode(String codestring,int width,int height){
        try {
            //首先判断参数的合法性，要求字符串内容不能为空或图片长宽必须大于0
            if (TextUtils.isEmpty(codestring)||width<=0||height<=0){
                return null;
            }
            //设置二维码的相关参数，生成BitMatrix（位矩阵）对象
            Hashtable<EncodeHintType,String> hashtable=new Hashtable<>();
            hashtable.put(EncodeHintType.CHARACTER_SET,"utf-8");  //设置字符转码格式
            hashtable.put(EncodeHintType.ERROR_CORRECTION,"H");   //设置容错级别
            hashtable.put(EncodeHintType.MARGIN,"2"); //设置空白边距
            //encode需要抛出和处理异常
            BitMatrix bitMatrix=new QRCodeWriter().encode(codestring, BarcodeFORMat.QR_CODE,width,height,hashtable);
            //再创建像素数组，并根据位矩阵为数组元素赋颜色值
            int[] pixel=new int[width*width];
            for (int h=0;h<height;h++){
                for (int w=0;w<width;w++){
                    if (bitMatrix.get(w,h)){
                        pixel[h*width+w]= Color.BLACK;  //设置黑色色块
                    }else{
                        pixel[h*width+w]=Color.WHITE;  //设置白色色块
                    }
                }
            }
            //创建bitmap对象
            //根据像素数组设置Bitmap每个像素点的颜色值，之后返回Bitmap对象
            Bitmap qrcodemap=Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);
            qrcodemap.setPixels(pixel,0,width,0,0,width,height);
            return qrcodemap;
        }catch (WriterException e){
            return null;
        }
    }
}

//点击开始生成按钮监听事件
startBt1.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        String input=inputEt.getText().toString();  //获取用户输入的字符串  
        //调用CreateUtil类生成二维码后显示在界面上
        contentIv.setImageBitmap(CreateUtil.createQRCode(input,contentIv.getWidth(),contentIv.getHeight()));
    }
});

        //开始扫描按钮点击事件监听
        startBt2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                scanQRCode();
            }
        });
    
 
 
 
    //实现扫描二维码的方法
    private void scanQRCode() {
        //申请相机权限
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, Constant.REQ_PERM_CAMERA);
            return;
        }
        //申请文件(相册)读写权限
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, Constant.REQ_PERM_EXTERNAL_STORAGE);
            return;
        }
        //二维码扫码
        //然后通过Intent机制启动zxing框架的CaptuReactivity，请求返回结果
        Intent intent = new Intent(this, CaptureActivity.class);
        startActivityForResult(intent, Constant.REQ_QR_CODE);
    }
 
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        //扫描结果回调
        if (requestCode == Constant.REQ_QR_CODE && resultCode == RESULT_OK) {
            Bundle bundle = data.getExtras();
            String scanResult = bundle.getString(Constant.INTENT_EXTRA_KEY_QR_SCAN);
            //将扫描出的信息显示出来
            resultTv.setText(scanResult);
        }
    }
 
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode){
            case Constant.REQ_PERM_CAMERA:
                //摄像头权限申请
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    //获得授权
                    scanQRCode();
                } else {
                    //被禁止授权
                    Toast.makeText(this, "请至权限中心打开本应用的相机访问权限", Toast.LENGTH_LONG).show();
                }
                break;
            case Constant.REQ_PERM_EXTERNAL_STORAGE:
                //文件读写权限申请
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    //获得授权
                    scanQRCode();
                } else {
                    //被禁止授权
                    Toast.makeText(this, "请至权限中心打开本应用的文件读写权限", Toast.LENGTH_LONG).show();
                }
                break;
        }
    }
}

implementation 'com.google.zxing:core:3.3.3'

 public static com.google.zxing.Result[] decodeQR(Bitmap srcBitmap) {
        com.google.zxing.Result[] result = null;
        if (srcBitmap != null) {
            int width = srcBitmap.getWidth();
            int height = srcBitmap.getHeight();
            int[] pixels = new int[width * height];
            srcBitmap.getPixels(pixels, 0, width, 0, 0, width, height);
            // 新建一个RGBLuminanceSource对象
            RGBLuminanceSource source = new RGBLuminanceSource(width, height, pixels);
            // 将图片转换成二进制图片
            BinaryBitmap binaryBitmap = new BinaryBitmap(new    
            GlobalHistogramBinarizer(source));
            QRCodeMultiReader reader = new QRCodeMultiReader();// 初始化解析对象
            try {
                result = reader.decodeMultiple(binaryBitmap, 
                CodeHintsUtils.getDefaultDecodeHints());// 解析获取一个Result数组
            } catch (NotFoundException e) {
                e.printStackTrace();
            }
        }
        return result;
    }