您错过了一个构造函数，

you missed a constructor,

public surfaceviewclass (Context context, AttributeSet attrs) {
     super(context, attrs);
}

编辑：

这是当视图被充气时调用构造函数从XML（构造）。你声明的属性由第二个参数提供

This is the constructor that is called when the view is inflated (constructed) from the xml. The attributes you declared are supplied by the second parameter