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();
}