Question

我在ZBarScannerActivity类中自定义Zbar API的摄像头视图。这是我添加的代码。

    setContentView(R.layout.scanner);

    mAutoFocusHandler = new Handler();

    // Create and configure the ImageScanner;
    setupScanner();

    // Create a RelativeLayout container that will hold a SurfaceView,
    // and set it as the content of our activity.
    mPreview = new CameraPreview(this, this, autoFocusCB);
    LinearLayout zbarLayout = (LinearLayout) findViewById(R.id.zbar_layout_area);
    mPreview.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
    zbarLayout.addView(mPreview);

然后当我运行应用程序时，相机预览错误，所以我使用setDisplayOrientation将其旋转到90.然后它已经旋转但摄像机视图被拉伸。这是我的CameraPreview代码。

private final String TAG = "CameraPreview";

SurfaceView mSurfaceView;
SurfaceHolder mHolder;
Size mPreviewSize;
List<Size> mSupportedPreviewSizes;
Camera mCamera;
PreviewCallback mPreviewCallback;
AutoFocusCallback mAutoFocusCallback;

CameraPreview(Context context, PreviewCallback previewCallback, AutoFocusCallback autoFocusCb) {
    super(context);

    mPreviewCallback = previewCallback;
    mAutoFocusCallback = autoFocusCb;
    mSurfaceView = new SurfaceView(context);

    addView(mSurfaceView);

    // Install a SurfaceHolder.Callback so we get notified when the
    // underlying surface is created and destroyed.
    mHolder = mSurfaceView.getHolder();
    mHolder.addCallback(this);
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}

public void setCamera(Camera camera) {
    mCamera = camera;
    if (mCamera != null) {
        mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
        requestLayout();
    }
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    // We purposely disregard child measurements because act as a
    // wrapper to a SurfaceView that centers the camera preview instead
    // of stretching it.
    final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
    final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
    setMeasuredDimension(width, height);

    if (mSupportedPreviewSizes != null) {
        mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
    }
}

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    if (changed && getChildCount() > 0) {
        final View child = getChildAt(0);

        final int width = r - l;
        final int height = b - t;

        int previewWidth = width;
        int previewHeight = height;
        if (mPreviewSize != null) {
            previewWidth = mPreviewSize.width;
            previewHeight = mPreviewSize.height;
        }

        // Center the child SurfaceView within the parent.
        if (width * previewHeight > height * previewWidth) {
            final int scaledChildWidth = previewWidth * height / previewHeight;
            child.layout((width - scaledChildWidth) / 2, 0,
                    (width + scaledChildWidth) / 2, height);
        } else {
            final int scaledChildHeight = previewHeight * width / previewWidth;
            child.layout(0, (height - scaledChildHeight) / 2,
                    width, (height + scaledChildHeight) / 2);
        }
    }
}

public void hideSurfaceView() {
    mSurfaceView.setVisibility(View.INVISIBLE);
}

public void showSurfaceView() {
    mSurfaceView.setVisibility(View.VISIBLE);
}

public void surfaceCreated(SurfaceHolder holder) {
    // The Surface has been created, acquire the camera and tell it where
    // to draw.
    try {
        if (mCamera != null) {
            mCamera.setPreviewDisplay(holder);
        }
    } catch (IOException exception) {
        Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
    }
}

public void surfaceDestroyed(SurfaceHolder holder) {
    // Surface will be destroyed when we return, so stop the preview.
    if (mCamera != null) {
        mCamera.cancelAutoFocus();
        mCamera.stopPreview();
    }
}


private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
    final double ASPECT_TOLERANCE = 0.1;
    double targetRatio = (double) w / h;
    if (sizes == null) return null;

    Size optimalSize = null;
    double minDiff = Double.MAX_VALUE;

    int targetHeight = h;

    // Try to find an size match aspect ratio and size
    for (Size size : sizes) {
        double ratio = (double) size.width / size.height;
        if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
        if (Math.abs(size.height - targetHeight) < minDiff) {
            optimalSize = size;
            minDiff = Math.abs(size.height - targetHeight);
        }
    }

    // Cannot find the one match the aspect ratio, ignore the requirement
    if (optimalSize == null) {
        minDiff = Double.MAX_VALUE;
        for (Size size : sizes) {
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }
    }
    Log.d("Edgar", optimalSize.width + "  " + optimalSize.height);
    return optimalSize;
}

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
    if (holder.getSurface() == null){
      // preview surface does not exist
      return;
    }

    if (mCamera != null) {
        // Now that the size is known, set up the camera parameters and begin
        // the preview.
        Camera.Parameters parameters = mCamera.getParameters();
        parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
        requestLayout();

        mCamera.setDisplayOrientation(90);
        mCamera.setParameters(parameters);
        mCamera.setPreviewCallback(mPreviewCallback);
        mCamera.startPreview();
        mCamera.autoFocus(mAutoFocusCallback);
    }
}

请帮我修理相机视图。谢谢你的帮助。

Answer 1

如果您尝试在纵向视图中进行查看，但基本上显示的是不会被挤压的横向视图门户网站＆＃39;那么我建议做一个预览在其他布局后面的布局。基本上你可以做到

<RelativeLayout
      android:layout_height="fill_parent"
      android:layout_width="fill_parent"
      >
       <FrameLayout
        android:id="@+id/camera_preview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">
            <LinearLayout
            android:id="@+id/ticket_overlay"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:orientation="vertical" >
            <... Some stuff here ... w/ background>
            <... spacer here ... w/ transparent to show view portal>
            <... Some stuff here ... w/ background>
       </LinearLayout>
    </FrameLayout>
</RelativeLayout>

Zbar Android自定义相机预览拉伸

1 个答案: