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copied!<p>I'm pretty new to Android programming, so I'm not 100% sure on the answer to your question. However, I recently implemented something similar, and I was getting errors when I was calling startPreview() if the preview size was not set correctly using the setParameters(...) method. Perhaps this problem is related.</p> <p>Here is the code that's working for me currently. This class was pulled from an example I found online, although I can't recall where.</p> <p><strong>EDIT:</strong> Found the original source I pulled this from: <a href="http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/CameraPreview.html" rel="nofollow">CameraPreview API Demo</a></p> <pre><code>// A simple wrapper around a Camera and a SurfaceView that renders a // centered preview of the Camera to the surface. We need to center the // SurfaceView because not all devices have cameras that support preview // sizes at the same aspect ratio as the device's display. class Preview extends ViewGroup implements SurfaceHolder.Callback { private final String TAG = "Preview"; SurfaceView mSurfaceView; SurfaceHolder mHolder; Size mPreviewSize; List<Size> mSupportedPreviewSizes; Camera mCamera; Preview(Context context) { super(context); 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 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.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); } } } return optimalSize; } public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { // 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.setParameters(parameters); mCamera.startPreview(); } </code></pre> <p>}</p>

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