UIButton *view = [UIButton.alloc initWithFrame:(CGRectMake(20, 100, 60, 40))];
view.backgroundColor = UIColor.orangeColor;
[MyRelativeLayout.view addSubview:view];

目前view的显示 frame 为 (0, 0, 60, 40)

期望view 的显示 frame 为 (20, 100, 60, 40)