无法使用 camerax 拍摄多张图像

Question

我正在尝试使用 camerax 拍摄多张照片，但只拍摄了第一张照片，代码和日志输出将显示我的意思。

这是代码：

        Log.d(TAG, "------------------ taking new picture1");
        mImageCapture.takePicture(new ImageCapture.OnImageCapturedListener() {
            @Override
            public void onCaptureSuccess(ImageProxy imageProxy, int rotationDegrees) {
                Image image = imageProxy.getImage();
                Log.d(TAG, "taking new picture onCapture Success 1 called");
            }

            @Override
            public void onError(ImageCapture.UseCaseError useCaseError, String message, @Nullable Throwable cause) {
                super.onError(useCaseError, message, cause);
                Log.d(TAG, "--------- error in image capture 1" + message);


            }
        });

        Log.d(TAG, "------------------ taking new picture 2");
        mImageCapture.takePicture(new ImageCapture.OnImageCapturedListener() {
            @Override
            public void onCaptureSuccess(ImageProxy imageProxy, int rotationDegrees) {
                Image image = imageProxy.getImage();
                Log.d(TAG, "taking new picture onCapture Success 2 called");


            }

            @Override
            public void onError(ImageCapture.UseCaseError useCaseError, String message, @Nullable Throwable cause) {
                super.onError(useCaseError, message, cause);
                Log.d(TAG, "--------- error in image capture 2" + message);
            }
        });

相关日志输出为：

2019-09-04 12:23:00.978 28970-29006/com.example.david.digified_android D/ScanDocumentFragment: ------------------ taking new picture1
2019-09-04 12:23:00.980 28970-29006/com.example.david.digified_android D/ScanDocumentFragment: ------------------ taking new picture 2
2019-09-04 12:23:02.063 28970-28970/com.example.david.digified_android D/ScanDocumentFragment: taking new picture onCapture Success 1 called

但 调用 Capture Success 2 拍摄新照片 从未发生过

虽然根据文档拍两张照片并没有错:

TakePicture returns immediately and a listener is called to provide the results after the capture completes. Multiple calls to takePicture will take pictures sequentially starting after the previous picture is captured.

https://developer.android.com/reference/androidx/camera/core/ImageCapture?hl=en

Answer 1

这似乎是库的问题，错误在这里： https://issuetracker.google.com/issues/140518887

更新根据团队对该问题的评论，这似乎不是错误，问题是我必须在完成处理后调用 image.close();，这样我的代码应该是：

Log.d(TAG, "------------------ taking new picture1");
mImageCapture.takePicture(new ImageCapture.OnImageCapturedListener() {
   @Override
   public void onCaptureSuccess(ImageProxy imageProxy, int rotationDegrees) {
      Image image = imageProxy.getImage();
      Log.d(TAG, "taking new picture onCapture Success 1 called");
      image.close();
   }

});

Log.d(TAG, "------------------ taking new picture 2");
mImageCapture.takePicture(new ImageCapture.OnImageCapturedListener() {
   @Override
   public void onCaptureSuccess(ImageProxy imageProxy, int rotationDegrees) {
      Image image = imageProxy.getImage();
      Log.d(TAG, "taking new picture onCapture Success 2 called");
      image.close();
   }
});

Answer 2

现象问题：

连续调用了两次mImageCapture.takePicture()，再次调用mImageCapture.takePicture()后没有任何反应。如果退出就会进入onError回调，提示找不到摄像头。

在这种情况下，你会发现控制台有如下两条信息：

D/ImageCapture：发送图片采集请求[current, pending] = [0, 1].

W/ImageCapture：获取的图像过多。关闭图片，以便处理下一张图片。

原因：

截取的图片太多，必须关闭到运行下。然后，查看ImageCapture的源码，搜索imageProxy.close()，发现有四个地方：两个地方在捕获时调用，两个地方判断暂时没有调用，即有一般情况下拍完照return成功后没有关闭，所以才会出现这个问题。

解决方案：

在mImageCapture.takePicture()的成功回调函数中，使用图片后手动关闭，即可解决此问题

mImageCapture.takePicture(new ImageCapture.OnImageCapturedListener(){
        @Override
        public void onCaptureSuccess(ImageProxy imageProxy, int rotationDegrees) {
            //Do something
            Log.d(TAG, "taking new picture onCapture Success 1 called");
            imageProxy.close();
        }

        @Override
        public void onError(ImageCapture.UseCaseError useCaseError, String message, @Nullable Throwable cause) {
            super.onError(useCaseError, message, cause);
            Log.d(TAG, "--------- error in image capture 1" + message);


        }
    });

资源：https://blog.csdn.net/qq_37980878/article/details/120060170

无法使用 camerax 拍摄多张图像

can't take multiple Images using camerax

android-camerax