Android constraintlayout 在约束图中从中心位置垂直偏移图像

我在屏幕上以图像为中心，如下所示：

<androidx.constraintlayout.motion.widget.ConstraintLayout
    android:id="@+id/dashboardConstraintLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.appcompat.widget.AppCompatImageView
        android:id="@+id/logo"
        android:layout_width="155dp"
        android:layout_height="20dp"
        android:scaleType="centerCrop"
        app:srcCompat="@drawable/ic_logo" 
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"/>

</androidx.constraintlayout.motion.widget.ConstraintLayout>

我想做的是让图像从中心位置向下偏移50dp。添加marginTop不起作用。所做的只是在屏幕顶部添加一个边距，图像将被约束。图像仍保留在中间。但我想把它调低50分

我试过了，效果很好，我强调了我修改过的代码

我试过了，效果很好，我强调了我修改过的代码





     <?xml version="1.0" encoding="utf-8"?>
     <androidx.constraintlayout.widget.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:layout_width="match_parent"
         android:layout_height="match_parent"
         tools:context=".Third">

         <androidx.appcompat.widget.AppCompatImageView //it is normar imageView in centered 
             android:id="@+id/logo"
             android:layout_width="155dp"
             android:layout_height="20dp"
             android:scaleType="centerCrop"
             android:src="@drawable/ic_launcher_background"
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toTopOf="parent"/>

         <androidx.appcompat.widget.AppCompatImageView //in this imageView i used marginTop and it works perfectly
             android:id="@+id/logo1"
             android:layout_width="155dp"
             android:layout_height="20dp"
             android:scaleType="centerCrop"
             android:src="@drawable/two"
             android:layout_marginTop="50dp"
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toTopOf="parent"/>

         <androidx.appcompat.widget.AppCompatImageView //in this imageView i used vertical_bias and it work perfectly.
             android:id="@+id/logo2"
             android:layout_width="155dp"
             android:layout_height="20dp"
             android:scaleType="centerCrop"
             android:src="@drawable/ic_launcher_background"
             app:layout_constraintVertical_bias="0.60"  //there is 0.0=Top,  0.50=center,  1.0=Bottom and so on.
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toTopOf="parent"/>
     </androidx.constraintlayout.widget.ConstraintLayout>