从相机，SurfaceView或SurfaceHolder连续获取图像数据

问题描述

因此我已将此摄像机预览设置为Camera，SurfaceView和SurfaceHolder.我还有一个ImageView，我将在其中放置摄像机图像的修改版本，并希望每秒更新一次.

So I have this camera preview set up with Camera, SurfaceView and SurfaceHolder.I have also an ImageView where I will be putting a modified version of the camera image and I want this to update lets say once every second.

当我从"res"加载图像时，所有代码均已准备就绪，并且已经可以使用，但是我很难从相机读取图像数据.

All code is ready and already working when I load images from "res" but I have a really hard time reading the image data from the camera.

我已经尝试过以下操作:

I've tried following already:

1. 为MediaStore.ACTION_IMAGE_CAPTURE创建intent并开始onActivityResult从(Bitmap)data.getExtras().get("data")
   
   获取小缩略图(实际上对我来说足够了)问题是，这会打开相机应用程序，您需要手动"拍照.

1. Creating an intent for MediaStore.ACTION_IMAGE_CAPTURE and starting an onActivityResult getting a small thumbnail (enough for me actually) from (Bitmap)data.getExtras().get("data")
   
   The problem is that this opens the camera App and you need to "manually" take a picture.

创建Camera.PreviewCallback，获取YuvImage，然后使用YuvImage.compressToJpeg(...)将其转换为图像.

这里的问题是，无论何时何地放置 Camera.setPreviewCallbackWithBuffer(PreviewCallback)，我都无法启动它.

Creating a Camera.PreviewCallback, taking the YuvImage, and converting it to an image using YuvImage.compressToJpeg(...).

The problem here is that I can't get it to start no matter when or where i put the Camera.setPreviewCallbackWithBuffer(PreviewCallback).

修改:使这项工作最好的方法是什么?我的意思是QR码阅读器必须连续从相机中读取图像数据，它们如何工作?

What is the best way to make this work? I mean QR-Code readers must read the image data out of the camera continuously, how do they work?

推荐答案

我去了第2个选项，终于使它起作用了.

I went for option number 2 and finally made it work.

使用了此回调，之前忘记了@Override

used this callback, forgot the @Override before

private Camera.PreviewCallback  previewCallback= new Camera.PreviewCallback()
{   
    @Override
    public void onPreviewFrame(byte[] data,Camera cam)
    {
            Camera.Size previewSize = cam.getParameters().getPreviewSize();
            YuvImage yuvImage = new YuvImage(data, ImageFormat.NV21,previewSize.width,previewSize.height, null);
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            yuvImage.compressToJpeg(new Rect(0,0,previewSize.width,previewSize.height),80,baos);
            byte[] jdata = baos.toByteArray();
            Bitmap bitmap = BitmapFactory.decodeByteArray(jdata,0,jdata.length);    
    }
};

并使用setPreviewCallback而不是setPreviewCallbackWithBuffer

SurfaceHolder.Callback surfaceCallback=new SurfaceHolder.Callback() 
{   
    public void surfaceCreated(SurfaceHolder holder) {

        camera.setPreviewCallback(previewCallback);
    }
}

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