android的ConstraintLayout布局的按钮实现了水平对齐，水平间距相等，我照着写了3个imageview，没有水平没对齐，水平间距也不相等
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/button7"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintLeft_toLeftOf="parent" />
<ImageView
android:id="@+id/services_1_1_p"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_dashboard_black_24dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintLeft_toLeftOf="parent" />
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/button8"
app:layout_constraintTop_toTopOf="@+id/button7"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toLeftOf="@+id/button7" />
<ImageView
android:id="@+id/services_1_2_p"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_dashboard_black_24dp"
app:layout_constraintTop_toTopOf="@+id/services_1_1_p"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toLeftOf="@+id/services_1_1_p"
/>
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/button9"
app:layout_constraintBaseline_toBaselineOf="@+id/button7"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintLeft_toRightOf="@+id/button7"
/>
<ImageView
android:id="@+id/services_1_3_p"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_dashboard_black_24dp"
app:layout_constraintBaseline_toBaselineOf="@+id/services_1_1_p"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintLeft_toRightOf="@+id/services_1_1_p"
/>