Android相机捏缩放

Question

我正在制作使用相机硬件的应用程序。我试图在相机视图中实现缩放缩放，但缩小功能不起作用，只是放大。这是我的代码：  public boolean onTouchEvent（MotionEvent event）{

    Camera.Parameters params = mCamera.getParameters();
    int action = event.getAction();


    if (event.getPointerCount() > 1) {

        if (action == MotionEvent.ACTION_POINTER_DOWN) {
            float mDist = getFingerSpacing(event);
        } else if (action == MotionEvent.ACTION_MOVE && params.isZoomSupported()) {
            mCamera.cancelAutoFocus();
            handleZoom(event, params);
        }
    } else {

        if (action == MotionEvent.ACTION_UP) {
            handleFocus(event, params);
        }
    }
    return true;
}

@SuppressWarnings("deprecation")
private void handleZoom(MotionEvent event, Camera.Parameters params) {
    int maxZoom = params.getMaxZoom();
    int zoom = params.getZoom();
    @SuppressWarnings("unused")
    int currnetZoom = params.getZoom();
    float newDist = getFingerSpacing(event);
    float mDist = 0;
    if (newDist > mDist) {
        if (zoom < maxZoom)
            zoom++;
    } else if (newDist <= mDist) {

        if (zoom >= 0)
            zoom--;
    }
    mDist = newDist;
    params.setZoom(zoom);
    mCamera.setParameters(params);
}

@SuppressWarnings("deprecation")
public void handleFocus(MotionEvent event, Camera.Parameters params) {
    int pointerId = event.getPointerId(0);
    int pointerIndex = event.findPointerIndex(pointerId);

    @SuppressWarnings("unused")
    float x = event.getX(pointerIndex);
    @SuppressWarnings("unused")
    float y = event.getY(pointerIndex);

    List<String> supportedFocusModes = params.getSupportedFocusModes();
    if (supportedFocusModes != null && supportedFocusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) {
        mCamera.autoFocus(new Camera.AutoFocusCallback() {
            @Override
            public void onAutoFocus(boolean b, Camera camera) {

            }
        });
    }
}

/** Determine the space between the first two fingers */
@SuppressWarnings("deprecation")
private float getFingerSpacing(MotionEvent event) {

    float x = event.getX(0) - event.getX(1);
    float y = event.getY(0) - event.getY(1);
    return FloatMath.sqrt(x * x + y * y);
}


    please I really need help. Thanks