Question

我需要在小型SurfaceView中设置Mobile Vision barcode scanner相机预览（屏幕高度的1/4）。如何在不缩小相机预览的情况下按比例进行操作？

Answer 1

我这样解决了。

在我的活动中添加了相机视图

    <com.superup.smartshelf.test.CroppedCameraPreview
        android:id="@+id/preview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

创建了CroppedCameraPreview类

public class CroppedCameraPreview extends ViewGroup {

    private static final String TAG = "qwe";
    private SurfaceView mSurfaceView;
    private boolean mStartRequested;
    private boolean mSurfaceAvailable;
    private CameraSource mCameraSource;
    private BarcodeDetector barcodeDetector;

    public CroppedCameraPreview(final Context context, AttributeSet attrs) {
        super(context, attrs);

        mSurfaceView = new SurfaceView(context);
        mSurfaceView.getHolder().addCallback(new SurfaceCallback());
        addView(mSurfaceView);
    }


    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int croppedWidth = getResources().getDisplayMetrics().widthPixels;
        int croppedHeight = getResources().getDisplayMetrics().heightPixels / 4;

        setMeasuredDimension(croppedWidth, croppedHeight);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        // crop view
        int actualPreviewWidth = getResources().getDisplayMetrics().widthPixels;
        int actualPreviewHeight = getResources().getDisplayMetrics().heightPixels;


        if (mSurfaceView != null) {
            mSurfaceView.layout(0, 0, actualPreviewWidth, actualPreviewHeight);
        }
    }

    public void start(CameraSource cameraSource) throws IOException {
        if (cameraSource == null) {
            stop();
        }

        mCameraSource = cameraSource;

        if (mCameraSource != null) {
            mStartRequested = true;
            startIfReady();
        }
    }

    public void stop() {
        if (mCameraSource != null) {
            mCameraSource.stop();
        }
    }

    public void release() {
        if (mCameraSource != null) {
            mCameraSource.release();
            mCameraSource = null;
        }
    }

    private void startIfReady() throws IOException {
        if (mStartRequested && mSurfaceAvailable) {
            mCameraSource.start(mSurfaceView.getHolder());
            /*if (mOverlay != null) {
                Size size = mCameraSource.getPreviewSize();
                int min = Math.min(size.getWidth(), size.getHeight());
                int max = Math.max(size.getWidth(), size.getHeight());
                if (isPortraitMode()) {
                    // Swap width and height sizes when in portrait, since it will be rotated by
                    // 90 degrees
                    mOverlay.setCameraInfo(min, max, mCameraSource.getCameraFacing());
                } else {
                    mOverlay.setCameraInfo(max, min, mCameraSource.getCameraFacing());
                }
                mOverlay.clear();
            }*/
            mStartRequested = false;
        }
    }

    private class SurfaceCallback implements SurfaceHolder.Callback {
        @Override
        public void surfaceCreated(SurfaceHolder surfaceHolder) {
            try {
                mCameraSource.start(mSurfaceView.getHolder());
            } catch (IOException e) {
                Log.e(TAG, "Could not start camera source.", e);
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {

        }

        @Override
        public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
            mCameraSource.stop();

        }
    }

}

并在我的活动中初始化它。 setLayoutParams允许设置视图的大小。

CroppedCameraPreview mPreview = (CroppedCameraPreview) findViewById(R.id.preview);

        // get display size
        final DisplayMetrics metrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metrics);

        //set camera view on 1/4 of the screen
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(metrics.widthPixels, metrics.heightPixels / 4);
        mPreview.setLayoutParams(layoutParams);

    BarcodeDetector barcodeDetector = new BarcodeDetector.Builder(this).build();
    BarcodeTrackerFactory barcodeFactory = new BarcodeTrackerFactory(
            new BarcodeTracker.NewDetectionListener() {
                @Override
                public void onNewDetection(Barcode barcode) {
                    final String rawBarcode = barcode.rawValue;
                    mPreview.post(new Runnable() {
                        public void run() {
                            String barcode = rawBarcode;
                            mediaPlayer.start();
                            mPreview.setVisibility(View.GONE);
                            Log.d(TAG, barcode);

                            // do all what you want with barcode

                            } else {
                                Toast.makeText(getApplicationContext(), "Barcode not found", Toast.LENGTH_SHORT).show();
                            }

                        }
                    });
                }
            });
    barcodeDetector.setProcessor(new MultiProcessor.Builder<>(barcodeFactory).build());


    mCameraSource = new CameraSource
            .Builder(this, barcodeDetector)
            .setAutoFocusEnabled(true)
            .build();
}

@Override
protected void onResume() {
    super.onResume();
    startCameraSource();
}

@Override
protected void onPause() {
    super.onPause();
    mPreview.stop();
}

@Override
protected void onDestroy() {
    super.onDestroy();
    mCameraSource.release();
}

private void startCameraSource() {
    try {
        mPreview.start(mCameraSource);
    } catch (IOException e) {
        Log.e(TAG, "Unable to start camera source.", e);
        mCameraSource.release();
        mCameraSource = null;
    }
}

Answer 2

只需使用imageView并将您的图像放在src属性中。这样就可以了（它有自动缩放功能）。

现在，如果您想要更多选项，可以使用＆＃34; android：adjustViewBounds = true＆＃34;和＆＃34; android：scaleType＆＃34;。

小视野中的移动视觉

2 个答案: