在设备上运行时，在xml设计视图上查看的约束布局不相同

Question

我正在使用约束布局来最小化LinearLayouts的使用，但我无法理解为什么我在预览中看到的不是它在模拟器或物理设备上运行时的实际情况。

This is preview layout

this is what looks like when run on a device

这是我的xml：     

<android.support.constraint.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android"                                                 
xmlns:app="http://schemas.android.com/apk/res-auto"                                             
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/conts"
android:layout_width="match_parent"

android:layout_height="match_parent"

android:background="@android:color/white"
tools:layout_editor_absoluteX="0dp"                                        
tools:layout_editor_absoluteY="89dp">

<ImageView
    android:id="@+id/iv_header"
    android:layout_width="379dp"
    android:layout_height="148dp"
    android:layout_marginEnd="8dp"
    android:layout_marginLeft="50dp"
    android:layout_marginRight="50dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="5dp"
    android:paddingTop="5dp"
    android:scaleType="fitXY"
    app:layout_constraintBottom_toTopOf="@+id/tvPg1_2"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/conts"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.0"
    app:layout_constraintVertical_weight="1"
    app:srcCompat="@drawable/tokhang_header" />

<TextView
    android:id="@+id/tvPg1_0"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginLeft="8dp"
    android:layout_marginRight="8dp"
    android:layout_marginTop="0dp"
    android:text="As of"
    android:textColor="@android:color/black"
    android:textSize="18sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="@+id/iv_header"
    app:layout_constraintHorizontal_bias="0.499"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.782"
    android:shadowColor="#FFFF4444"
    android:shadowDx="-2"
    android:shadowDy="-2"
    android:shadowRadius="1"/>

<TextView
    android:id="@+id/tvPg1_1"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginLeft="8dp"
    android:layout_marginRight="150dp"
    android:layout_marginStart="8dp"
    android:background="@drawable/tokang_pg1_1antidrugopn"
    android:gravity="top|center"
    android:paddingLeft="55dp"
    android:text="700"
    android:textAlignment="center"
    android:textColor="@android:color/black"
    android:textScaleX="1"
    android:textSize="30sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toTopOf="@+id/tvPg1_2"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/iv_header"
    app:layout_constraintVertical_weight="1"
    android:shadowColor="#FFFF4444"
    android:shadowDx="-2"
    android:shadowDy="-2"
    android:shadowRadius="1"/>

<TextView
    android:id="@+id/tvPg1_2"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginLeft="150dp"
    android:layout_marginRight="8dp"
    android:layout_marginStart="8dp"
    android:background="@drawable/tokang_pg1_2drugpers"
    android:gravity="top|center"
    android:paddingLeft="25dp"
    android:text="700"
    android:textAlignment="center"
    android:textColor="@android:color/black"
    android:textScaleX="1"
    android:textSize="30sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toTopOf="@+id/tvPg1_3"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/tvPg1_1"
    app:layout_constraintVertical_weight="1"
    android:shadowColor="#FFFF4444"
    android:shadowDx="-2"
    android:shadowDy="-2"
    android:shadowRadius="1"/>

<TextView
    android:id="@+id/tvPg1_3"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginBottom="0dp"
    android:layout_marginEnd="8dp"
    android:layout_marginLeft="8dp"
    android:layout_marginRight="150dp"
    android:layout_marginStart="8dp"
    android:background="@drawable/tokang_pg1_3drugpersdied"
    android:gravity="top|center"
    android:paddingLeft="10dp"
    android:text="700"
    android:textAlignment="center"
    android:textColor="@android:color/black"
    android:textScaleX="1"
    android:textSize="30sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toTopOf="@+id/tvPg1_4"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/tvPg1_2"
    app:layout_constraintVertical_weight="1"
    android:shadowColor="#FFFF4444"
    android:shadowDx="-2"
    android:shadowDy="-2"
    android:shadowRadius="1"/>

<TextView
    android:id="@+id/tvPg1_4"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginLeft="150dp"
    android:layout_marginRight="8dp"
    android:layout_marginStart="8dp"
    android:background="@drawable/tokang_pg1_4housevisited"
    android:gravity="top|center"
    android:paddingLeft="35dp"
    android:paddingTop="15dp"
    android:text="700"
    android:textAlignment="center"
    android:textColor="@android:color/black"
    android:textScaleX="1"
    android:textSize="30sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toTopOf="@+id/imageView2"
    app:layout_constraintHorizontal_bias="0.496"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/tvPg1_3"
    app:layout_constraintVertical_weight="1"
    android:shadowColor="#FFFF4444"
    android:shadowDx="-2"
    android:shadowDy="-2"
    android:shadowRadius="1"/>

<ImageView
    android:id="@+id/imageView2"
    android:layout_width="match_parent"
    android:layout_height="122dp"
    android:layout_marginEnd="0dp"
    android:layout_marginLeft="0dp"
    android:layout_marginRight="0dp"
    android:layout_marginStart="8dp"
    android:scaleType="fitXY"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/tvPg1_4"
    app:layout_constraintVertical_bias="1.0"
    app:layout_constraintVertical_weight="1"
    app:srcCompat="@drawable/tokhang_footer" />


</android.support.constraint.ConstraintLayout>

每当我打开xml时，布局会发生变化或者不对齐，我必须撤消我做任何更改。似乎约束布局不稳定或者我不稳定是新手。 你知道发生了什么吗？

提前感谢您的帮助。