ConstraintLayout.LayoutParams params = (ConstraintLayout.LayoutParams)mBuyTV.getLayoutParams();
params.bottomMargin = ScreenUtils.getScreenHeight(this) - ScreenUtils.dp2px(this, 380f);
当不起作用时加上下面
mBuyTV.setLayoutParams(params);
ConstraintLayout.LayoutParams params = (ConstraintLayout.LayoutParams)mBuyTV.getLayoutParams();
params.bottomMargin = ScreenUtils.getScreenHeight(this) - ScreenUtils.dp2px(this, 380f);
当不起作用时加上下面
mBuyTV.setLayoutParams(params);