EMVideoCallHelper callHelper.setRenderFlag(true);

// 显示对方图像的surfaceview
        oppositeSurface = (SurfaceView) findViewById(R.id.opposite_surface);
        oppositeSurfaceHolder = oppositeSurface.getHolder();
        // 设置显示对方图像的surfaceview
        callHelper.setSurfaceView(oppositeSurface);