Question

我正在尝试使用相机api2来捕捉图像。代码在MOTO g4上工作正常，但是当我在NEXUS 6上测试代码时，在session.capture之后没有调用onImageAvailable，也没有保存图像。非常沮丧，非常感谢有人可以提供帮助！非常感谢。

        ImageReader reader = ImageReader.newInstance(width, height, ImageFormat.JPEG, 1);
        List<Surface> outputSurfaces = new ArrayList<Surface>(2);
        outputSurfaces.add(reader.getSurface());
        outputSurfaces.add(new Surface(textureView.getSurfaceTexture()));
        final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
        captureBuilder.addTarget(reader.getSurface());
        captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
        // Orientation
        int rotation = getWindowManager().getDefaultDisplay().getRotation();
        captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));
        sendUri = getImageUri();
        final File file = new File(Environment.getExternalStorageDirectory()+"/"  + sendUri +".jpg");
        ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener() {
            @Override
            public void onImageAvailable(ImageReader reader) {
                Image image = null;
                try {
                    image = reader.acquireLatestImage();
                    ByteBuffer buffer = image.getPlanes()[0].getBuffer();
                    byte[] bytes = new byte[buffer.capacity()];
                    buffer.get(bytes);
                    save(bytes);

                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    if (image != null) {
                        image.close();
                    }
                }
            }
            private void save(byte[] bytes) throws IOException {
                OutputStream output = null;
                try {
                    output = new FileOutputStream(file);
                    output.write(bytes);
                } finally {
                    if (null != output) {
                        output.close();
                    }
                }
            }
        };
        reader.setOnImageAvailableListener(readerListener, mBackgroundHandler);
        final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() {

            @Override
            public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
                super.onCaptureCompleted(session, request, result);
                //Toast.makeText(MainActivity.this, "Saved:" + file, Toast.LENGTH_SHORT).show();
                toast1("Saved:"+file);
                //createCameraPreview();
            }
        };
        cameraDevice.createCaptureSession(outputSurfaces, new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(CameraCaptureSession session) {
                try {
                    session.capture(captureBuilder.build(), captureListener, mBackgroundHandler);
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                }
            }
            @Override
            public void onConfigureFailed(CameraCaptureSession session) {
            }
        }, mBackgroundHandler);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }

以下是运行相机功能时来自nexus 6的完整logcat输出，似乎没什么用处......

03-07 13:04:34.526 1838-1838/examples.hello E/AndroidCameraApi: is camera open
03-07 13:04:34.527 1838-1838/examples.hello I/CameraManagerGlobal: Connecting to camera service
03-07 13:04:34.659 1838-1838/examples.hello E/AndroidCameraApi: openCamera X
03-07 13:04:34.694 1838-1838/examples.hello E/AndroidCameraApi: onOpened
03-07 13:04:34.722 1838-1883/examples.hello D/OpenGLRenderer: endAllActiveAnimators on 0x931bee80 (RippleDrawable) with handle 0x92c2cea0
03-07 13:04:43.952 1838-1838/examples.hello E/AndroidCameraApi: onPause

Answer 1

如果你从失败的设备中包含完整的logcat输出会有所帮助，但我怀疑问题是这样的：

ImageReader reader = ImageReader.newInstance(width, height, ImageFormat.JPEG, 1);

您正在创建一个本地ImageReader对象，而不是将其保存以供进一步使用。你从它得到一个Surface，但是Surface很像一个弱指针;如果没有引用它，它将不会阻止ImageReader获取GC（请参阅note in the developer references）

所以我怀疑如果你只是创建一个类成员mReader变量，并将读者存储在其中，一切都会正常工作。

由于GC算法的差异，它可能正在使用Moto手机;运行时还没有完全清除读者对象，所以它有时间调用回调。

Answer 2

像这样覆盖onConfigureFailed()：

   @Override
   public void onConfigureFailed(CameraCaptureSession session) {
       ImageReader mReader = ImageReader.newInstance(640, 480, ImageFormat.JPEG, 1);
       takePicture() // function to get image
       createCameraPreview(); // function to set camera Preview on screen
   }

调用createCameraPreview函数重新启动相机，否则它将卡住。您可以使用新值更改ImageReader

ImageReader mReader = ImageReader.newInstance(640, 480, ImageFormat.JPEG, 1);

然后再次调用takePicture()函数，以便用户不必再次单击即可捕获图像。

在camera.capture之后没有调用android camera2 api - onImageAvailable

2 个答案: