我从 opencv4android(人脸检测)复制了示例代码。我通过了NDK部分。并在手机上运行该应用程序。然而 SurfaceView 仅显示相机预览。看来 OnCameraFrame 中所做的任何操作都不会影响 SurfaceView 上的 Canvas。所以我追踪了他们的 SDK。问题出在 DeliverAndDrawFrame 函数中。以前有人遇到过同样的问题吗?
Canvas canvas = getHolder().lockCanvas();
if (canvas != null) {
canvas.drawColor(0, android.graphics.PorterDuff.Mode.CLEAR);
Log.d(TAG, "mStretch value: " + mScale);
if (mScale != 0) {
canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
new Rect((int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2),
(int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2),
(int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2 + mScale*mCacheBitmap.getWidth()),
(int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2 + mScale*mCacheBitmap.getHeight())), null);
} else {
canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
new Rect((canvas.getWidth() - mCacheBitmap.getWidth()) / 2,
(canvas.getHeight() - mCacheBitmap.getHeight()) / 2,
(canvas.getWidth() - mCacheBitmap.getWidth()) / 2 + mCacheBitmap.getWidth(),
(canvas.getHeight() - mCacheBitmap.getHeight()) / 2 + mCacheBitmap.getHeight()), null);
}
if (mFpsMeter != null) {
mFpsMeter.measure();
mFpsMeter.draw(canvas, 20, 30);
}
getHolder().unlockCanvasAndPost(canvas);
}
Error:
10-09 21:57:47.485 28018-28088/com.example.tim.r3dmobileclient E/SurfaceHolder﹕ Exception locking surface
java.lang.IllegalArgumentException
at android.view.Surface.nativeLockCanvas(Native Method)
at android.view.Surface.lockCanvas(Surface.java:253)
at android.view.SurfaceView$4.internalLockCanvas(SurfaceView.java:848)
at android.view.SurfaceView$4.lockCanvas(SurfaceView.java:816)
at org.opencv.android.CameraBridgeViewBase.deliverAndDrawFrame(CameraBridgeViewBase.java:412)
at org.opencv.android.JavaCameraView$CameraWorker.run(JavaCameraView.java:348)
at java.lang.Thread.run(Thread.java:841)