Android ConstraintLayout约束布局的居中

Android ConstraintLayout约束布局的居中

xml代码：

<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent"> <TextView android:id="@+id/text1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@android:color/holo_red_light" android:text="text1：顶部水平居中" android:textColor="@android:color/white" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> <TextView android:id="@+id/text2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@android:color/holo_red_light" android:text="text2：位于text1下且水平居中" android:textColor="@android:color/white" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toBottomOf="@id/text1" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@android:color/holo_green_light" android:text="水平居中，且居于text2下" android:textColor="@android:color/white" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toBottomOf="@id/text2" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@android:color/holo_red_light" android:text="居中位于底部" android:textColor="@android:color/white" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@android:color/holo_blue_bright" android:text="全局居中" android:textColor="@android:color/white" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> </android.support.constraint.ConstraintLayout> 

输出结果如图：