Android 我修改了onPreviewFrame里返回的预览数据，怎么将修改后的数据显示到屏幕上

Question

网上东拼西凑起来的demo，有很多不解，求大神不吝指导

我将onPreviewFrame的data在异步中去处理，处理完成后，我怎么让处理后的数据显示到屏幕上，

protected Object doInBackground(Object[] params) {
        Camera.Parameters parameters = mCamera.getParameters();
        int imageWidth = parameters.getPreviewSize().width;
        int imageHeight = parameters.getPreviewSize().height;
        int RGBData[] = new int[imageWidth * imageHeight];
        decodeYUV420SP(RGBData, mData, imageWidth, imageHeight);// 解码，yuv420sp转为RGB格式
        Bitmap bm = Bitmap.createBitmap(RGBData, imageWidth, imageHeight, Bitmap.Config.ARGB_8888);//填到bitmap中
        //图片旋转才能正常识别人脸
        int cameraId = 1;
        bm = rotateBitmap(bm, cameraId == 0 ? 90 : 270);

        if (bm == null) {
            Log.d(TAG, "无可用图片!!!");
            return null;
        }
        JniClient jni = new JniClient();
        int width = bm.getWidth();
        int height = bm.getHeight();

        //把bitmap中的ARGB_8888格式转为Mat矩阵中可用的BGRA格式数据bgra
        // 计算位图所占用的内存字节数 getRowBytes()*getHeight()
        int bytes = bm.getByteCount();
        ByteBuffer buffer = ByteBuffer.allocate(bytes); // Create a new buffer
        bm.copyPixelsToBuffer(buffer); // Move the byte data to the buffer
        byte[] bs = buffer.array(); // Get the underlying array containing the

        //计算图像通道数ch
        int ch = bs.length / (width * height);
        if (ch < 1) {
            ch = 1;
        }
        mFaceByte = bs;
        mWidth1 = width;
        mHeight1 = height;
        mCh1 = mFaceByte.length / (width * height);
        //计算图像通道数ch
        if (mCh1 < 1) {
            mCh1 = 1;
        }

        //剪切的人脸图像
        Bitmap tFaceBmp = Bitmap.createBitmap(256, 256, Bitmap.Config.ARGB_8888);
        long t = System.currentTimeMillis();
        String tRetStr = jni.CMDetectFace(bs, width, height, ch, "/storage/emulated/0/Android/data/system/", 1, tFaceBmp);
        t = System.currentTimeMillis() - t;
        Log.e("监测人脸，获取人脸范围及5个点的坐标共花费时间", "" + t);

        if (TextUtils.isEmpty(tRetStr) || tRetStr.equals("")) {
            Log.d(TAG, "没有人脸");
        } else {
            //分解字符串，获取脸的位置
            String[] tFaceStrs = tRetStr.split(";");
            int face_num = tFaceStrs.length;

            Bitmap bitmap2 = bm.copy(Bitmap.Config.ARGB_8888, true);
            mCanvas = new Canvas(bitmap2);
            Paint paint = new Paint();

            int tStokeWid = 1 + (width + height) / 300;
            paint.setColor(Color.RED);
            paint.setStyle(Paint.Style.STROKE);//不填充
            paint.setStrokeWidth(tStokeWid);  //线的宽度

            for (int i = 0; i < face_num; i++) {
                String[] vals = tFaceStrs[i].split(",");
                int x = Integer.valueOf(vals[0]);
                int y = Integer.valueOf(vals[1]);
                int w = Integer.valueOf(vals[2]);
                int h = Integer.valueOf(vals[3]);
                int left = x;
                int top = y;
                int right = x + w;
                int bottom = y + w;

                mCanvas.drawRect(left, top, right, bottom, paint);
                if (vals.length < 5) {
                    continue;
                }
                //画特征点
                for (int j = 0; j < 5; j++) {
                    int ti = 4 + j * 2;
                    int px = Integer.valueOf(vals[ti]);
                    int py = Integer.valueOf(vals[ti + 1]);
                    Log.i("loadimg", "j=" + j + ",px=" + px + ", py=" + py);
                    mCanvas.drawCircle(px, py, tStokeWid, paint);
                }
            }

        }
        return null;

    }

Answer 1

Il s'agit d'un sous-thread, qui peut être utilisé pour traiter les données. L'étape suivante consiste à transmettre l'objet de données traitées au thread principal, puis à l'afficher au lieu de le dessiner dans le sous-thread. L'utilisation de Handler.post (new Runnable) devrait répondre à vos besoins.