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自定义 UI 下使用扫码功能

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本文将引导您绘制自定义 UI 界面并将自定义 UI 扫码的能力添加到工程中。

如需在自定义 UI 下使用扫码功能,请参考 代码示例

该过程主要分为以下四个步骤:

  1. 创建依赖工程

  2. 在依赖工程中创建定义 UI 界面

  3. 在依赖工程中使用扫码功能

  4. 在主工程中调用自定义 UI 下的扫码功能

操作步骤

创建依赖工程

  1. 单击 File > New > New Module

  2. 选择 Android Library,单击 Next

  3. 输入 Module name,单击 Finish

在依赖工程中创建定义 UI 界面

  1. customcom.example.custom 包中创建 widget 包。在 widget 包中添加 APSurfaceTexture 类,让其继承 SurfaceTexture 类,以获取图像流。

    public class APSurfaceTexture extends SurfaceTexture {
    
     private static final String TAG = "APSurfaceTexture";
    
     public SurfaceTexture mSurface;
    
     public APSurfaceTexture() {
         super(0);
     }
    
     @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
     @Override
     public void attachToGLContext(int texName) {
         mSurface.attachToGLContext(texName);
     }
    
     @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
     @Override
     public void detachFromGLContext() {
         try {
             mSurface.detachFromGLContext();
         } catch (Exception ex) {
             try {
                 Method nativeMethod = SurfaceTexture.class.getDeclaredMethod("nativeDetachFromGLContext");
                 nativeMethod.setAccessible(true);
                 int retCode = (Integer) nativeMethod.invoke(mSurface);
                 LoggerFactory.getTraceLogger().debug(TAG, "nativeDetachFromGLContext invoke retCode:" + retCode);
             } catch (Exception e) {
                 LoggerFactory.getTraceLogger().error(TAG, "nativeDetachFromGLContext invoke exception:" + e.getMessage());
             }
             LoggerFactory.getTraceLogger().error(TAG, "mSurface.detachFromGLContext() exception:" + ex.getMessage());
         }
     }
    
     @Override
     public boolean equals(Object o) {
         return mSurface.equals(o);
     }
    
     @Override
     public long getTimestamp() {
         return mSurface.getTimestamp();
     }
    
     @Override
     public void getTransformMatrix(float[] mtx) {
         mSurface.getTransformMatrix(mtx);
     }
    
     @Override
     public void release() {
         super.release();
         mSurface.release();
     }
    
     @Override
     public int hashCode() {
         return mSurface.hashCode();
     }
    
     @TargetApi(Build.VERSION_CODES.KITKAT)
     @Override
     public void releaseTexImage() {
         mSurface.releaseTexImage();
     }
    
     @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1)
     @Override
     public void setDefaultBufferSize(int width, int height) {
         mSurface.setDefaultBufferSize(width, height);
     }
    
     @Override
     public void setOnFrameAvailableListener(OnFrameAvailableListener listener) {
         mSurface.setOnFrameAvailableListener(listener);
     }
    
     @Override
     public String toString() {
         return mSurface.toString();
     }
    
     @Override
     public void updateTexImage() {
         mSurface.updateTexImage();
     }
    }
  2. customwidget 包中添加 APTextureView 类,让其继承 TextureView 类,实现图像流的显示。

    public class APTextureView extends TextureView {
    
     private static final String TAG = "APTextureView";
    
     private Field mSurfaceField;
    
     public APTextureView(Context context) {
         super(context);
     }
    
     public APTextureView(Context context, AttributeSet attrs) {
         super(context, attrs);
     }
    
     public APTextureView(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
     }
    
     @Override
     protected void onDetachedFromWindow() {
         try {
             super.onDetachedFromWindow();
         } catch (Exception ex) {
             LoggerFactory.getTraceLogger().error(TAG, "onDetachedFromWindow exception:" + ex.getMessage());
         }
     }
    
     @Override
     public void setSurfaceTexture(SurfaceTexture surfaceTexture) {
         super.setSurfaceTexture(surfaceTexture);
         afterSetSurfaceTexture();
     }
    
     private void afterSetSurfaceTexture() {
         LoggerFactory.getTraceLogger().debug(TAG, "afterSetSurfaceTexture Build.VERSION.SDK_INT:" + Build.VERSION.SDK_INT);
         if (Build.VERSION.SDK_INT < 16 || Build.VERSION.SDK_INT > 20) {
             return;
         }
    
         try {
             if (mSurfaceField == null) {
                 mSurfaceField = TextureView.class.getDeclaredField("mSurface");
                 mSurfaceField.setAccessible(true);
             }
    
             SurfaceTexture innerSurface = (SurfaceTexture) mSurfaceField.get(this);
             if (innerSurface != null) {
                 if (!(innerSurface instanceof APSurfaceTexture)) {
                     APSurfaceTexture wrapSurface = new APSurfaceTexture();
                     wrapSurface.mSurface = innerSurface;
                     mSurfaceField.set(this, wrapSurface);
                     LoggerFactory.getTraceLogger().debug(TAG, "afterSetSurfaceTexture wrap mSurface");
                 }
             }
         } catch (Exception ex) {
             LoggerFactory.getTraceLogger().error(TAG, "afterSetSurfaceTexture exception:" + ex.getMessage());
         }
     }
    }
  3. com.example.custom 包中创建 Utils 类,实现图片的转换。

    public class Utils {
    
     private static String TAG = "Utils";
    
     public static void toast(Context context, String msg) {
         Toast.makeText(context, msg, Toast.LENGTH_SHORT).show();
     }
    
     public static Bitmap changeBitmapColor(Bitmap bitmap, int color) {
         int bitmap_w = bitmap.getWidth();
         int bitmap_h = bitmap.getHeight();
         int[] arrayColor = new int[bitmap_w * bitmap_h];
    
         int count = 0;
         for (int i = 0; i < bitmap_h; i++) {
             for (int j = 0; j < bitmap_w; j++) {
    
                 int originColor = bitmap.getPixel(j, i);
                 // 非透明区域
                 if (originColor != 0) {
                     originColor = color;
                 }
    
                 arrayColor[count] = originColor;
                 count++;
             }
         }
         return Bitmap.createBitmap(arrayColor, bitmap_w, bitmap_h, Bitmap.Config.ARGB_8888);
     }
    
     public static Bitmap uri2Bitmap(Context context, Uri uri) {
         Bitmap bitmap = null;
         InputStream in;
         try {
             in = context.getContentResolver().openInputStream(uri);
             if (in != null) {
                 bitmap = BitmapFactory.decodeStream(in);
                 in.close();
             }
         } catch (Exception e) {
             LoggerFactory.getTraceLogger().error(TAG, "uri2Bitmap: Exception " + e.getMessage());
         }
         return bitmap;
     }
    }
  4. custom 中创建 res > values > attrs.xml 文件并添加如下代码。

    <?xml version="1.0" encoding="utf-8"?>
    <resources>
     <declare-styleable name="scan">
         <attr name="shadowColor" format="color" />
     </declare-styleable>
    </resources>
  5. customres > drawable 文件夹中粘贴如下 资源文件

    12
  6. customwidget 包中添加 FinderView 类,让其继承 View 类,并添加如下代码。实现扫码窗口、边角及周边阴影的绘制功能。

    public class FinderView extends View {
    
    private static final int DEFAULT_SHADOW_COLOR = 0x96000000;
    
    private int scanWindowLeft, scanWindowTop, scanWindowRight, scanWindowBottom;
    private Bitmap leftTopCorner, rightTopCorner, leftBottomCorner, rightBottomCorner;
    private Paint paint;
    private int shadowColor;
    
    public FinderView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs);
    }
    
    public FinderView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs);
    }
    
    private void init(Context context, AttributeSet attrs) {
        applyConfig(context, attrs);
        setVisibility(INVISIBLE);
        initCornerBitmap(context);
    
        paint = new Paint();
        paint.setAntiAlias(true);
    }
    
    private void applyConfig(Context context, AttributeSet attrs) {
        if (attrs != null) {
            TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.scan);
            shadowColor = typedArray.getColor(R.styleable.scan_shadowColor, DEFAULT_SHADOW_COLOR);
            typedArray.recycle();
        }
    }
    //初始化扫码窗口边角样式
    private void initCornerBitmap(Context context) {
        Resources res = context.getResources();
        leftTopCorner = BitmapFactory.decodeResource(res, R.drawable.scan_window_corner_left_top);
        rightTopCorner = BitmapFactory.decodeResource(res, R.drawable.scan_window_corner_right_top);
        leftBottomCorner = BitmapFactory.decodeResource(res, R.drawable.scan_window_corner_left_bottom);
        rightBottomCorner = BitmapFactory.decodeResource(res, R.drawable.scan_window_corner_right_bottom);
    }
    
    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        drawShadow(canvas);
        drawCorner(canvas);
    }
    //绘制扫码窗口边角样式
    private void drawCorner(Canvas canvas) {
        paint.setAlpha(255);
        canvas.drawBitmap(leftTopCorner, scanWindowLeft, scanWindowTop, paint);
        canvas.drawBitmap(rightTopCorner, scanWindowRight - rightTopCorner.getWidth(), scanWindowTop, paint);
        canvas.drawBitmap(leftBottomCorner, scanWindowLeft, scanWindowBottom - leftBottomCorner.getHeight(), paint);
        canvas.drawBitmap(rightBottomCorner, scanWindowRight - rightBottomCorner.getWidth(), scanWindowBottom - rightBottomCorner.getHeight(), paint);
    }
    //绘制扫码周边阴影
    private void drawShadow(Canvas canvas) {
        paint.setColor(shadowColor);
        canvas.drawRect(0, 0, getWidth(), scanWindowTop, paint);
        canvas.drawRect(0, scanWindowTop, scanWindowLeft, scanWindowBottom, paint);
        canvas.drawRect(scanWindowRight, scanWindowTop, getWidth(), scanWindowBottom, paint);
        canvas.drawRect(0, scanWindowBottom, getWidth(), getHeight(), paint);
    }
    
    /**
     * 根据 RayView 的位置决定扫码窗口的位置
     */
    public void setScanWindowLocation(int left, int top, int right, int bottom) {
        scanWindowLeft = left;
        scanWindowTop = top;
        scanWindowRight = right;
        scanWindowBottom = bottom;
        invalidate();
        setVisibility(VISIBLE);
    }
    
    public void setShadowColor(int shadowColor) {
        this.shadowColor = shadowColor;
    }
    //设置扫码窗口边角颜色
    public void setCornerColor(int angleColor) {
        leftTopCorner = Utils.changeBitmapColor(leftTopCorner, angleColor);
        rightTopCorner = Utils.changeBitmapColor(rightTopCorner, angleColor);
        leftBottomCorner = Utils.changeBitmapColor(leftBottomCorner, angleColor);
        rightBottomCorner = Utils.changeBitmapColor(rightBottomCorner, angleColor);
    }
    }
  7. customwidget 包中添加 RayView 类,让其继承 ImageView 类,并添加如下代码。实现扫描射线的绘制功能。

    public class RayView extends ImageView {
    
    private FinderView mFinderView;
    private ScaleAnimation scanAnimation;
    private int[] location = new int[2];
    
    public RayView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    
    public RayView(Context context) {
        super(context);
    }
    
    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
    
        // 设置 FinderView 中扫码窗口的位置
        getLocationOnScreen(location);
        if (mFinderView != null) {
            mFinderView.setScanWindowLocation(location[0], location[1], location[0] + getWidth(), location[1] + getHeight());
        }
    }
    
    public void startScanAnimation() {
        setVisibility(VISIBLE);
        if (scanAnimation == null) {
            scanAnimation = new ScaleAnimation(1.0f, 1.0f, 0.0f, 1.0f);
            scanAnimation.setDuration(3000L);
            scanAnimation.setFillAfter(true);
            scanAnimation.setRepeatCount(Animation.INFINITE);
            scanAnimation.setInterpolator(new AccelerateDecelerateInterpolator());
        }
        startAnimation(scanAnimation);
    }
    
    public void stopScanAnimation() {
        setVisibility(INVISIBLE);
        if (scanAnimation != null) {
            this.clearAnimation();
            scanAnimation = null;
        }
    }
    
    public void setFinderView(FinderView FinderView) {
        mFinderView = FinderView;
    }
    }
  8. customres 中创建 layout > File > view_scan.xml 文件,并添加如下代码,绘制扫描页面的布局界面。

    <?xml version="1.0" encoding="utf-8"?>
    <merge xmlns:android="http://schemas.android.com/apk/res/android">
    
        <com.example.custom.widget.FinderView
            android:id="@+id/finder_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:gravity="center_vertical"
            android:orientation="horizontal">
    
            <ImageView
                android:id="@+id/back"
                android:layout_width="48dp"
                android:layout_height="48dp"
                android:scaleType="center"
                android:src="@drawable/icon_back" />
    
            <TextView
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:gravity="center"
                android:text="@string/custom_title"
                android:textColor="#ffffff"
                android:textSize="16sp" />
    
            <ImageView
                android:id="@+id/gallery"
                android:layout_width="34dp"
                android:layout_height="34dp"
                android:layout_marginEnd="10dp"
                android:layout_marginRight="10dp"
                android:scaleType="fitXY"
                android:src="@drawable/selector_scan_from_gallery" />
    
            <ImageView
                android:id="@+id/torch"
                android:layout_width="34dp"
                android:layout_height="34dp"
                android:layout_marginEnd="10dp"
                android:layout_marginRight="10dp"
                android:scaleType="fitXY"
                android:src="@drawable/selector_torch" />
        </LinearLayout>
    
        <com.example.custom.widget.RayView
            android:id="@+id/ray_view"
            android:layout_width="270dp"
            android:layout_height="280dp"
            android:layout_centerInParent="true"
            android:background="@drawable/custom_scan_ray" />
    
        <TextView
            android:id="@+id/tip_tv"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/ray_view"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="10dp"
            android:includeFontPadding="false"
            android:text="@string/scan_tip"
            android:textColor="#7fffffff"
            android:textSize="14sp" />
    
    </merge>
  9. widget 包中添加 ScanView 类,让其继承 RelativeLayout 类,并添加如下代码。实现扫码相关的 View 与扫码引擎的交互功能。

    public class ScanView extends RelativeLayout {
    
    private RayView mRayView;
    
    public ScanView(Context context) {
        super(context);
        init(context);
    }
    
    public ScanView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context);
    }
    
    public ScanView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context);
    }
    
    private void init(Context ctx) {
        LayoutInflater.from(ctx).inflate(R.layout.view_scan, this, true);
        FinderView finderView = (FinderView) findViewById(R.id.finder_view);
        mRayView = (RayView) findViewById(R.id.ray_view);
        mRayView.setFinderView(finderView);
    }
    
    public void onStartScan() {
        mRayView.startScanAnimation();
    }
    
    public void onStopScan() {
        mRayView.stopScanAnimation();
    }
    
    public float getCropWidth() {
        return mRayView.getWidth() * 1.1f;
    }
    
    public Rect getScanRect(Camera camera, int previewWidth, int previewHeight) {
        if (camera == null) {
            return null;
        }
        int[] location = new int[2];
        mRayView.getLocationOnScreen(location);
        Rect r = new Rect(location[0], location[1],
                location[0] + mRayView.getWidth(), location[1] + mRayView.getHeight());
        Camera.Size size;
        try {
            size = camera.getParameters().getPreviewSize();
        } catch (Exception e) {
            return null;
        }
        if (size == null) {
            return null;
        }
        double rateX = (double) size.height / (double) previewWidth;
        double rateY = (double) size.width / (double) previewHeight;
        // 裁剪框大小 = 网格动画框大小*1.1
        int expandX = (int) (mRayView.getWidth() * 0.05);
        int expandY = (int) (mRayView.getHeight() * 0.05);
        Rect resRect = new Rect(
                (int) ((r.top - expandY) * rateY),
                (int) ((r.left - expandX) * rateX),
                (int) ((r.bottom + expandY) * rateY),
                (int) ((r.right + expandX) * rateX));
    
        Rect finalRect = new Rect(
                resRect.left < 0 ? 0 : resRect.left,
                resRect.top < 0 ? 0 : resRect.top,
                resRect.width() > size.width ? size.width : resRect.width(),
                resRect.height() > size.height ? size.height : resRect.height());
    
        Rect rect1 = new Rect(
                finalRect.left / 4 * 4,
                finalRect.top / 4 * 4,
                finalRect.right / 4 * 4,
                finalRect.bottom / 4 * 4);
    
        int max = Math.max(rect1.right, rect1.bottom);
        int diff = Math.abs(rect1.right - rect1.bottom) / 8 * 4;
    
        Rect rect2;
        if (rect1.right > rect1.bottom) {
            rect2 = new Rect(rect1.left, rect1.top - diff, max, max);
        } else {
            rect2 = new Rect(rect1.left - diff, rect1.top, max, max);
        }
        return rect2;
    }
    }
  10. customlayout 文件夹中创建 activity_custom_scan.xml 文件并添加如下代码。绘制自定义扫码功能的主界面。

    <?xml version="1.0" encoding="utf-8"?>
    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    
        <com.mpaas.aar.demo.custom.widget.APTextureView
            android:id="@+id/surface_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    
        <com.mpaas.aar.demo.custom.widget.ScanView
            android:id="@+id/scan_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    
    </FrameLayout>

在依赖工程中使用扫码功能

  1. customcom.example.custom 包中添加 ScanHelper 类,并添加如下代码。调用扫码功能以及获取扫码结果的回调结果。

    public class ScanHelper {
    
     private static class Holder {
         private static ScanHelper instance = new ScanHelper();
     }
    
     private ScanCallback scanCallback;
    
     private ScanHelper() {
     }
    
     public static ScanHelper getInstance() {
         return Holder.instance;
     }
    
     public void scan(Context context, ScanCallback scanCallback) {
         if (context == null) {
             return;
         }
         this.scanCallback = scanCallback;
         context.startActivity(new Intent(context, CustomScanActivity.class));
     }
    
     void notifyScanResult(boolean isProcessed, Intent resultData) {
         if (scanCallback != null) {
             scanCallback.onScanResult(isProcessed, resultData);
             scanCallback = null;
         }
     }
    
     public interface ScanCallback {
         void onScanResult(boolean isProcessed, Intent result);
     }
    }
  2. customcom.example.custom 包中添加 CustomScanActivity 类,让其继承 Activity 类。设置界面沉浸模式并创建资源文件对应的 ViewButton

    public class CustomScanActivity extends Activity {
     private final String TAG = CustomScanActivity.class.getSimpleName();
     private static final int REQUEST_CODE_PERMISSION = 1;
     private static final int REQUEST_CODE_PHOTO = 2;
     private ImageView mTorchBtn;
     private APTextureView mTextureView;
     private ScanView mScanView;
     private boolean isFirstStart = true;
     private boolean isPermissionGranted;
     private boolean isScanning;
     private boolean isPaused;
     private Rect scanRect;
     private MPScanner mpScanner;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_custom_scan);
    
         // 设置沉浸模式
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
             getWindow().setFlags(
                     WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS,
                     WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
         }
    
         mTextureView = findViewById(R.id.surface_view);
         mScanView = findViewById(R.id.scan_view);
         mTorchBtn = findViewById(R.id.torch);
    
     }
    
      @Override
     public void onPause() {
         super.onPause();
    
     }
    
     @Override
     public void onResume() {
         super.onResume();
    
     }
    
     @Override
     public void onDestroy() {
         super.onDestroy();
    
     }
    
     @Override
     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
         super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    
     }
      @Override
     public void onBackPressed() {
         super.onBackPressed();
    
     }
    
     @Override
     public void onActivityResult(int requestCode, int resultCode, Intent data) {
         super.onActivityResult(requestCode, resultCode, data);
    
     }
    }
  3. 实现打开手机相册的功能。

    1. CustomScanActivity 中创建 pickImageFromGallery 方法。

      private void pickImageFromGallery() {
       Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
       intent.setType("image/*");
       startActivityForResult(intent, REQUEST_CODE_PHOTO);
      }
    2. onCreate 方法中添加 gallery 的单击事件,并调用 pickImageFromGallery 方法。

       findViewById(R.id.gallery).setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               pickImageFromGallery();
           }
       });
  4. 实现切换手电开关的功能。

    1. CustomScanActivity 中创建 switchTorch 方法。

       private void switchTorch() {
           boolean torchOn = mpScanner.switchTorch();
           mTorchBtn.setSelected(torchOn);
       }
    2. onCreate 方法中添加 mTorchBtn 的单击事件,并调用 switchTorch 方法。

      mTorchBtn.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View v) {
                   switchTorch();
               }
           });
  5. CustomScanActivity 中创建 notifyScanResult 方法,onBackPressed 中调用 notifyScanResult 方法。

     private void notifyScanResult(boolean isProcessed, Intent resultData) {
         ScanHelper.getInstance().notifyScanResult(isProcessed, resultData);
     }
    
     @Override
     public void onBackPressed() {
         super.onBackPressed();
         notifyScanResult(false, null);
     }
  6. CustomScanActivityonCreate 方法中添加 back 的单击事件,并调用 onBackPressed 方法。

         findViewById(R.id.back).setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
                 onBackPressed();
             }
         });
  7. CustomScanActivity 中创建 initMPScanner 方法,并使用 mpScanner 对象的 setRecognizeType 方法设置识别码的类型。

    private void initMPScanner() {
        mpScanner = new MPScanner(this);
        mpScanner.setRecognizeType(
                MPRecognizeType.QR_CODE,
                MPRecognizeType.BAR_CODE,
                MPRecognizeType.DM_CODE,
                MPRecognizeType.PDF417_CODE
        );
    }
  8. CustomScanActivity 中创建 onScanSuccess 方法,并实现如下代码。

    private void onScanSuccess(final MPScanResult result) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                if (result == null) {
                    notifyScanResult(true, null);
                } else {
                    Intent intent = new Intent();
                    intent.setData(Uri.parse(result.getText()));
                    notifyScanResult(true, intent);
                }
                CustomScanActivity.this.finish();
            }
        });
    }
  9. CustomScanActivity 中创建 initScanRect 方法,初始化扫描功能。

    1. 调用 mpScanner 对象的 getCamera 方法获取 Camera 对象并调用 mpScanner 对象的 setScanRegion 方法设置扫描区域。

      private void initScanRect() {
       if (scanRect == null) {
           scanRect = mScanView.getScanRect(
                   mpScanner.getCamera(), mTextureView.getWidth(), mTextureView.getHeight());
      
           float cropWidth = mScanView.getCropWidth();
           LoggerFactory.getTraceLogger().debug(TAG, "cropWidth: " + cropWidth);
           if (cropWidth > 0) {
               // 预览放大 = 屏幕宽 / 裁剪框宽
               WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
               float screenWith = wm.getDefaultDisplay().getWidth();
               float screenHeight = wm.getDefaultDisplay().getHeight();
               float previewScale = screenWith / cropWidth;
               if (previewScale < 1.0f) {
                   previewScale = 1.0f;
               }
               if (previewScale > 1.5f) {
                   previewScale = 1.5f;
               }
               LoggerFactory.getTraceLogger().debug(TAG, "previewScale: " + previewScale);
               Matrix transform = new Matrix();
               transform.setScale(previewScale, previewScale, screenWith / 2, screenHeight / 2);
               mTextureView.setTransform(transform);
           }
       }
       mpScanner.setScanRegion(scanRect);
      }
    2. 使用 mpScanner 对象的 setMPScanListener 方法实现扫描监听器的功能。

      mpScanner.setMPScanListener(new MPScanListener() {
          @Override
          public void onConfiguration() {
              mpScanner.setDisplayView(mTextureView);
          }
      
          @Override
          public void onStart() {
              if (!isPaused) {
                  runOnUiThread(new Runnable() {
                      @Override
                      public void run() {
                          if (!isFinishing()) {
                              initScanRect();
                              mScanView.onStartScan();
                          }
                      }
                  });
              }
          }
      
          @Override
          public void onSuccess(MPScanResult mpScanResult) {
              mpScanner.beep();
              onScanSuccess(mpScanResult);
          }
      
          @Override
          public void onError(MPScanError mpScanError) {
              if (!isPaused) {
                  runOnUiThread(new Runnable() {
                      @Override
                      public void run() {
                          Utils.toast(CustomScanActivity.this, getString(R.string.camera_open_error));
                      }
                  });
              }
          }
      });
    3. 使用 mpScanner 对象的 setMPImageGrayListener 方法实现识别图像灰度值的监听功能。

      mpScanner.setMPImageGrayListener(new MPImageGrayListener() {
          @Override
          public void onGetImageGray(int gray) {
              // 注意:该回调在昏暗环境下可能会连续多次执行
              if (gray < MPImageGrayListener.LOW_IMAGE_GRAY) {
                  runOnUiThread(new Runnable() {
                      @Override
                      public void run() {
                          Utils.toast(CustomScanActivity.this, "光线太暗,请打开手电筒");
                      }
                  });
              }
          }
      });
      }
  10. CustomScanActivity 中分别创建 startScanstopScan 方法,实现开启和关闭相机扫码权限。

    private void startScan() {
        try {
            mpScanner.openCameraAndStartScan();
            isScanning = true;
        } catch (Exception e) {
            isScanning = false;
            LoggerFactory.getTraceLogger().error(TAG, "startScan: Exception " + e.getMessage());
        }
    }
    
    private void stopScan() {
        mpScanner.closeCameraAndStopScan();
        mScanView.onStopScan();
        isScanning = false;
        if (isFirstStart) {
            isFirstStart = false;
        }
    }
  11. CustomScanActivity 中创建 onPermissionGranted 方法、checkCameraPermission 方法和 scanFromUri 方法。

    private void onPermissionGranted() {
        isPermissionGranted = true;
        startScan();
    }
    
    private void checkCameraPermission() {
        if (PermissionChecker.checkSelfPermission(
                this, Manifest.permission.CAMERA) != PermissionChecker.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, REQUEST_CODE_PERMISSION);
        } else {
            onPermissionGranted();
        }
    }
    
    private void scanFromUri(Uri uri) {
        final Bitmap bitmap = Utils.uri2Bitmap(this, uri);
        if (bitmap == null) {
            notifyScanResult(true, null);
            finish();
        } else {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    MPScanResult mpScanResult = mpScanner.scanFromBitmap(bitmap);
                    mpScanner.beep();
                    onScanSuccess(mpScanResult);
                }
            }, "scanFromUri").start();
        }
    }
  12. CustomScanActivityonCreate 方法中调用 checkCameraPermission 方法检查相机权限。

    checkCameraPermission();
  13. CustomScanActivityonPauseonResumeonDestroyonRequestPermissionsResultonActivityResult 方法中分别添加如下内容。

    @Override
    public void onPause() {
        super.onPause();
        isPaused = true;
        if (isScanning) {
            stopScan();
        }
    }
    
    @Override
    public void onResume() {
        super.onResume();
        isPaused = false;
        if (!isFirstStart && isPermissionGranted) {
            startScan();
        }
    }
    
    @Override
    public void onDestroy() {
        super.onDestroy();
        mpScanner.release();
    }   
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == REQUEST_CODE_PERMISSION) {
            int length = Math.min(permissions.length, grantResults.length);
            for (int i = 0; i < length; i++) {
                if (TextUtils.equals(permissions[i], Manifest.permission.CAMERA)) {
                    if (grantResults[i] != PackageManager.PERMISSION_GRANTED) {
                        Utils.toast(this, getString(R.string.camera_no_permission));
                    } else {
                        onPermissionGranted();
                    }
                    break;
                }
            }
        }
          @Override
        public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (data == null) {
            return;
        }
        if (requestCode == REQUEST_CODE_PHOTO) {
            scanFromUri(data.getData());
        }
    }
    }
  14. customAndroidManifest.xml 文件中设置 CustomScanActivitycustom 的主入口。

    <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.mpaas.aar.demo.custom">
    
        <application>
            <activity
                android:name=".CustomScanActivity"
                android:configChanges="orientation|keyboardHidden|navigation"
                android:exported="false"
                android:launchMode="singleTask"
                android:screenOrientation="portrait"
                android:theme="@android:style/Theme.NoTitleBar"
                android:windowSoftInputMode="adjustResize|stateHidden" />
        </application>
    
    </manifest>

在主工程中调用自定义 UI 下的扫码功能

  1. activity_main.xml 文件中,添加 Button,并设置 Button 的 ID 为 custom_ui_btn

     <Button
         android:id="@+id/custom_ui_btn"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_marginTop="208dp"
         android:background="#108EE9"
         android:gravity="center"
         android:text="自定义 UI 下使用扫一扫"
         android:textColor="#ffffff"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintHorizontal_bias="0.0"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
  2. MainActivity 类中编写代码。添加 custom_ui_btn 按钮的单击事件。获取自定义 UI 界面,并使用自定义 UI 的扫码功能。代码如下所示:

    findViewById(R.id.custom_ui_btn).setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
                 ScanHelper.getInstance().scan(MainActivity.this, new ScanHelper.ScanCallback() {
                     @Override
                     public void onScanResult(boolean isProcessed, Intent result) {
                         if (!isProcessed) {
                             // 扫码界面单击物理返回键或左上角返回键
                             return;
                         }
    
                         if (result == null || result.getData() == null) {
                             Toast.makeText(MainActivity.this, "扫码失败,请重试!", Toast.LENGTH_SHORT).show();
                             return;
                         }
                         new AlertDialog.Builder(MainActivity.this)
                                 .setMessage(result.getData().toString())
                                 .setPositiveButton(R.string.confirm, null)
                                 .create()
                                 .show();
                     }
                 });
             }
         });
  3. 编译运行工程后,单击 自定义 UI 下使用扫一扫 后即可使用自定义 UI 下的扫码功能。

  4. 扫描二维码,会弹出该二维码的信息。

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