<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintDimensionRatio="h,2:1"
android:background="@color/colorPrimary"/>
</androidx.constraintlayout.widget.ConstraintLayout>
当app:layout_constraintDimensionRatio=“h,2:1” 中写了h的情况下代表高宽比 2 ： 1
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintDimensionRatio="w,1:2"
android:background="@color/colorPrimary"/>
</androidx.constraintlayout.widget.ConstraintLayout>
当app:layout_constraintDimensionRatio=“w,1:2” 中写了w的情况下代表宽高比1 ： 2