ConstraintLayout遇到的小错误

最新的Android Studio中创建的Activity默认使用约束布局--------ConstraintLayout. 1) 在约束布局中添加Button控件后,发现xml飘红了! 如图一所示: 2)报错信息为:"This view is not constrained, it only has designtime positions, so it will jump to (0,0)..

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