添加 自定义的view，并显示在最前端

          View view1=new View(MainActivity.this);            int x=getResources().getDisplayMetrics().widthPixels;            int y=getResources().getDisplayMetrics().heightPixels;            view1.setX(100);            view1.setY(100);            ConstraintLayout layout=(ConstraintLayout)findViewById(R.id.main);            view1.setBackgroundColor(Color.RED);                ConstraintLayout.LayoutParams layoutParams=new ConstraintLayout.LayoutParams(400,500);                view1.setLayoutParams(layoutParams);//                     layout.addView(view1,layoutParams);            if (Build.VERSION.SDK_INT>=21)            {                view1.setTranslationZ(100.0f);            }            else{                view1.bringToFront();                layout.requestLayout();                view1.invalidate();            }