如何在从 TextureRegistry.SurfaceTextureEntry 创建的表面上绘制

Question

我想在flutter中使用Texture，然后使用java绘制TextureRegistry.SurfaceTextureEntry创建的表面；但我无法使用从表面获取的画布绘制矩形；

    TextureRegistry.SurfaceTextureEntry entry = textures.createSurfaceTexture();
    SurfaceTexture surfaceTexture = entry.surfaceTexture();
    Surface surface = new Surface(surfaceTexture);
    Canvas canvas = surface.lockCanvas(null);
    Paint paint = new Paint();
    paint.setColor(Color.BLUE);
    canvas.drawColor(Color.RED); 
    canvas.drawRect(0, 0,100 , 100, paint); 
    surface.unlockCanvasAndPost(canvas);
    result.success(entry.id());

我得到没有矩形的纯蓝色页面，如果我画

canvas.drawRect(1, 1,100 , 100, paint); 

我完全变红了；

我只想知道如何绘制从 Flutter 的 TextureRegistry.SurfaceTextureEntry 创建的表面。任何这样的例子也可以，但我找不到它;