imageview - 在 ConstraintLayout 中有一个具有相同宽度和高度的 ImageView

Question

我们如何使 ImageView 的宽度和高度等于父 ConstraintLayout 的宽度？所以它显示一个全宽的方形 ImageView。

通常如何设置某个小部件的高度等于其他小部件的宽度？

Answer 1

以下布局将在父级 ConstraintLayout 的中心放置一个方形蓝色图像。 .关键是app:layout_constraintDimensionRatio="1:1" .引用 documentation详情。

You can also define one dimension of a widget as a ratio of the other one. In order to do that, you need to have at least one constrained dimension be set to 0dp (i.e., MATCH_CONSTRAINT), and set the attribute layout_constraintDimensionRatio to a given ratio.

<android.support.constraint.ConstraintLayout 
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="@android:color/holo_blue_light"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintDimensionRatio="1:1"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>