Android 计算器布局优化

<androidx.constraintlayout.widget.ConstraintLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="30dp"> </androidx.constraintlayout.widget.ConstraintLayout> <androidx.constraintlayout.widget.ConstraintLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp"> </androidx.constraintlayout.widget.ConstraintLayout> <androidx.constraintlayout.widget.ConstraintLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp"> </androidx.constraintlayout.widget.ConstraintLayout> <androidx.constraintlayout.widget.ConstraintLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp"> <androidx.constraintlayout.widget.ConstraintLayout android:id="@+id/btn_container" android:layout_width="wrap_content" android:layout_height="wrap_content" app:layout_constraintTop_toTopOf="parent" app:layout_constraintStart_toStartOf="parent"> </androidx.constraintlayout.widget.ConstraintLayout> </androidx.constraintlayout.widget.ConstraintLayout>