Question

问题：活动会在负载时自动扫描心率我想要的是：我想在按下按钮后开始扫描心率。

我还是新手，所以有人可以帮助我吗？我很乐意欣赏它。

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main2);

    preview = (SurfaceView) findViewById(R.id.preview);
    previewHolder = preview.getHolder();
    previewHolder.addCallback(surfaceCallback);
    previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

    image = findViewById(R.id.image);
    text = (TextView) findViewById(R.id.text);

    PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
    wakeLock = pm
            .newWakeLock(PowerManager.FULL_WAKE_LOCK, "DoNotDimScreen");
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
}

@Override
public void onResume() {
    super.onResume();

    wakeLock.acquire();

    camera = Camera.open();

    startTime = System.currentTimeMillis();
}
@Override
public void onPause() {
    super.onPause();

    wakeLock.release();

    camera.setPreviewCallback(null);
    camera.stopPreview();
    camera.release();
    camera = null;
}

private static PreviewCallback previewCallback = new PreviewCallback() {
    @Override
    public void onPreviewFrame(byte[] data, Camera cam) {
        if (data == null)
            throw new NullPointerException();
        Camera.Size size = cam.getParameters().getPreviewSize();
        if (size == null)
            throw new NullPointerException();

        if (!processing.compareAndSet(false, true))
            return;

        int width = size.width;
        int height = size.height;

        int imgAvg = ImageProcessing.decodeYUV420SPtoRedAvg(data.clone(),
                height, width);
        // Log.i(TAG, "imgAvg="+imgAvg);
        if (imgAvg == 0 || imgAvg == 255) {
            processing.set(false);
            return;
        }

        int averageArrayAvg = 0;
        int averageArrayCnt = 0;
        for (int i = 0; i < averageArray.length; i++) {
            if (averageArray[i] > 0) {
                averageArrayAvg += averageArray[i];
                averageArrayCnt++;
            }
        }

        int rollingAverage = (averageArrayCnt > 0) ? (averageArrayAvg / averageArrayCnt)
                : 0;
        TYPE newType = currentType;
        if (imgAvg < rollingAverage) {
            newType = TYPE.RED;
            if (newType != currentType) {
                beats++;
                // Log.d(TAG, "BEAT!! beats="+beats);
            }
        } else if (imgAvg > rollingAverage) {
            newType = TYPE.GREEN;
        }

        if (averageIndex == averageArraySize)
            averageIndex = 0;
        averageArray[averageIndex] = imgAvg;
        averageIndex++;

        // Transitioned from one state to another to the same
        if (newType != currentType) {
            currentType = newType;
            image.postInvalidate();
        }

        long endTime = System.currentTimeMillis();
        double totalTimeInSecs = (endTime - startTime) / 1000d;
        if (totalTimeInSecs >= 10) {
            double bps = (beats / totalTimeInSecs);
            int dpm = (int) (bps * 60d);
            if (dpm < 30 || dpm > 180) {
                startTime = System.currentTimeMillis();
                beats = 0;
                processing.set(false);
                return;
            }

            // Log.d(TAG,
            // "totalTimeInSecs="+totalTimeInSecs+" beats="+beats);

            if (beatsIndex == beatsArraySize)
                beatsIndex = 0;
            beatsArray[beatsIndex] = dpm;
            beatsIndex++;

            int beatsArrayAvg = 0;
            int beatsArrayCnt = 0;
            for (int i = 0; i < beatsArray.length; i++) {
                if (beatsArray[i] > 0) {
                    beatsArrayAvg += beatsArray[i];
                    beatsArrayCnt++;
                }
            }
            int beatsAvg = (beatsArrayAvg / beatsArrayCnt);
            text.setText(String.valueOf(beatsAvg));
            startTime = System.currentTimeMillis();
            beats = 0;
        }
        processing.set(false);
    }
};

private static SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            camera.setPreviewDisplay(previewHolder);
            camera.setPreviewCallback(previewCallback);
        } catch (Throwable t) {
            Log.e("PreviewDemo-surfaceCallback",
                    "Exception in setPreviewDisplay()", t);
        }
    }
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        Camera.Parameters parameters = camera.getParameters();
        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
        Camera.Size size = getSmallestPreviewSize(width, height, parameters);
        if (size != null) {
            parameters.setPreviewSize(size.width, size.height);
            Log.d(TAG, "Using width=" + size.width + " height="
                    + size.height);
        }
        camera.setParameters(parameters);
        camera.startPreview();
    }
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // Ignore
    }
};

private static Camera.Size getSmallestPreviewSize(int width, int height,
        Camera.Parameters parameters) {
    Camera.Size result = null;

    for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
        if (size.width <= width && size.height <= height) {
            if (result == null) {
                result = size;
            } else {
                int resultArea = result.width * result.height;
                int newArea = size.width * size.height;

                if (newArea < resultArea)
                    result = size;
            }
        }
    }

    return result;
}

}

Answer 1

如果我理解你想在activity只在点击按钮时加载时你想做什么？

如果有，请创建Button并将您的逻辑移至onClick()

protected void onCreate(Bundle arg){
  ...

  Button button = (Button)findViewById(R.id.id_of_your_button);
  button.setOnClickListener(new OnClickListener{
       public void onClick(View v){
          wakeLock.acquire();

          camera = Camera.open();

         startTime = System.currentTimeMillis();

    }
    });
}

并从onResume()

中删除代码

启动时禁用自动扫描手指。

1 个答案: