OnPreviewFrame 数据图像到 imageView

问题描述

我正在尝试从相机的预览中获取字节 []，将其转换为位图并使用 imageView.setImageBitmap() 将其显示在图像视图上

i'm trying to get the byte[] from the preview of the camera, convert it to bitmap and display it on a imageview with imageView.setImageBitmap()

我已经设法开始预览并将其显示在surfaceView上，但我不知道如何将字节[]数据(我认为是Yuv格式)转换为RGB位图以将其显示在图像视图.

i've managed to start the preview and display it on a surfaceView, but i don't know how to convert the byte[] data (that comes in Yuv format i think) in a RGB bitmap to display it on a imageView.

我正在尝试的代码如下:

the code i'm trying is the following:

camera = camera.open();
parameters = camera.getParameters();
camera.setParameters(parameters);
surfaceHolder = surfaceView.getHolder();
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
camera.setPreviewDisplay(surfaceHolder);
camera.setPreviewCallback(this);
camera.startPreview();

预览回调是这样的

@Override
public void onPreviewFrame(byte[] data, Camera camera) {

    Camera.Parameters parameters = camera.getParameters();
    int width = parameters.getPreviewSize().width;
    int height = parameters.getPreviewSize().height;
    ByteArrayOutputStream outstr = new ByteArrayOutputStream();
    Rect rect = new Rect(0, 0, width, height);
    YuvImage yuvimage=new YuvImage(data,ImageFormat.NV21,width,height,null);
    yuvimage.compressToJpeg(rect, 100, outstr);
    Bitmap bmp = BitmapFactory.decodeByteArray(outstr.toByteArray(), 0, outstr.size());
    imgView1.setImageBitmap(bmp);
}

预览有效，但 imageView 仍为空

The preview works but the imageView remains empty

有什么想法吗?

推荐答案

可能您没有在 UI 线程中打开相机.但是，您需要确保在 UI 线程中调用 setImageBitmap:

It is possible you did not open the Camera in the UI thread. However, you need to ensure setImageBitmap is called in the UI thread:

@Override
public void onPreviewFrame(final byte[] data, Camera camera) {
    Camera.Parameters parameters = camera.getParameters();
    int width = parameters.getPreviewSize().width;
    int height = parameters.getPreviewSize().height;

    YuvImage yuv = new YuvImage(data, parameters.getPreviewFormat(), width, height, null);

    ByteArrayOutputStream out = new ByteArrayOutputStream();
    yuv.compressToJpeg(new Rect(0, 0, width, height), 50, out);

    byte[] bytes = out.toByteArray();
    final Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);

    MyActivity.this.runOnUiThread(new Runnable() {

        @Override
        public void run() {
            ((ImageView) findViewById(R.id.loopback)).setImageBitmap(bitmap);
        }
    });
}

这篇关于OnPreviewFrame 数据图像到 imageView的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！