用于打开相机和扫描二维码的Android API？

Question

我正在尝试开发一款可以打开相机并扫描给定二维码的应用。但是，我有一个限制，声明我不能使用任何第 3 方库，如 ZBar Code Reader 或 ZXingScanner，因为它会增加我的 apk 的大小。

我正在调查 Google 的条形码 API，给出 here ，但它似乎没有执行我希望我的应用程序执行的操作，也就是说，它没有打开任何相机并对图像进行实时扫描。

那么，如何让我的应用在特定范围内打开相机并对二维码执行实时扫描？

感谢您的宝贵时间!

Answer 1

Google barcode api 提供对开启相机的支持。这是示例代码

    // A barcode detector is created to track barcodes.  An associated multi-processor instance
    // is set to receive the barcode detection results, track the barcodes, and maintain
    // graphics for each barcode on screen.  The factory is used by the multi-processor to
    // create a separate tracker instance for each barcode.
    BarcodeDetector barcodeDetector = new BarcodeDetector.Builder(context).build();
    BarcodeTrackerFactory barcodeFactory = new BarcodeTrackerFactory(mGraphicOverlay);
    barcodeDetector.setProcessor(
            new MultiProcessor.Builder<>(barcodeFactory).build());

    if (!barcodeDetector.isOperational()) {
        // Note: The first time that an app using the barcode or face API is installed on a
        // device, GMS will download a native libraries to the device in order to do detection.
        // Usually this completes before the app is run for the first time.  But if that
        // download has not yet completed, then the above call will not detect any barcodes
        // and/or faces.
        //
        // isOperational() can be used to check if the required native libraries are currently
        // available.  The detectors will automatically become operational once the library
        // downloads complete on device.
        Log.w(TAG, "Detector dependencies are not yet available.");

        // Check for low storage.  If there is low storage, the native library will not be
        // downloaded, so detection will not become operational.
        IntentFilter lowstorageFilter = new IntentFilter(Intent.ACTION_DEVICE_STORAGE_LOW);
        boolean hasLowStorage = registerReceiver(null, lowstorageFilter) != null;

        if (hasLowStorage) {
            Toast.makeText(this, R.string.low_storage_error, Toast.LENGTH_LONG).show();
            Log.w(TAG, getString(R.string.low_storage_error));
        }
    }

    // Creates and starts the camera.  Note that this uses a higher resolution in comparison
    // to other detection examples to enable the barcode detector to detect small barcodes
    // at long distances.
    CameraSource.Builder builder = new CameraSource.Builder(getApplicationContext(), barcodeDetector)
            .setFacing(CameraSource.CAMERA_FACING_BACK)
            .setRequestedPreviewSize(1600, 1024)
            .setRequestedFps(15.0f);

    // make sure that auto focus is an available option
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
        builder = builder.setFocusMode(
                autoFocus ? Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE : null);
    }

    mCameraSource = builder
            .setFlashMode(useFlash ? Camera.Parameters.FLASH_MODE_TORCH : null)
            .build();
}

你可以在这里引用谷歌条形码示例

https://github.com/googlesamples/android-vision/tree/master/visionSamples/barcode-reader