使用constraintlayout的百分比保证金？

Question

我正在学习如何使用ConstraintLayout并找到一些好的教程,以百分比形式查看宽度和高度.我知道我可以添加一个空视图来'创建'边距,但它似乎不对.有办法marginEnd='10%'吗？

Answer 1

使用ConstraintLayout有两种方法可以添加百分比边际.

#1指南

只需将垂直指南添加到布局和约束视图中即可:

<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">

    <View
        android:id="@+id/view"
        android:layout_width="0dp"
        android:layout_height="50dp"
        android:background="@color/colorAccent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/guideline"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.9" />

</android.support.constraint.ConstraintLayout>

#2约束重量

添加空格,将其放置在父级的左侧,将视图和空间分组为"展开"链并设置app:layout_constraintHorizontal_weight="90"为视图和app:layout_constraintHorizontal_weight="10"空间.它与LinearLayout的重量非常相似.

<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">

    <View
        android:id="@+id/view"
        android:layout_width="0dp"
        android:layout_height="50dp"
        android:background="@color/colorAccent"
        app:layout_constraintHorizontal_chainStyle="spread"
        app:layout_constraintHorizontal_weight="90"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/space"
        app:layout_constraintBottom_toBottomOf="parent" />

    <Space
        android:id="@+id/space"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintHorizontal_weight="10"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toEndOf="@+id/view"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toBottomOf="parent" />

</android.support.constraint.ConstraintLayout>

因此,您的视图的结束边距值为父宽度的10%:

Answer 2

技巧#3：

双方的百分比

 app:layout_constraintWidth_percent=".80"

Answer 3

您可能需要嵌套约束

app:layout_constraintWidth_percent="0.9"
    app:layout_constraintHorizontal_bias="0.25"

没有偏见的 XML 示例：

<?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">

    <android.support.constraint.ConstraintLayout
        android:layout_width="0dp"
        android:layout_height="50dp"
        android:orientation="vertical"
        android:focusable="true"
        android:focusableInTouchMode="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintWidth_percent="0.9">
        <View
            android:id="@+id/view"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:background="@color/colorAccent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"/>
        </android.support.constraint.ConstraintLayout>

</android.support.constraint.ConstraintLayout>

带有偏差的 Xml 示例

<?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">

    <android.support.constraint.ConstraintLayout
        android:layout_width="0dp"
        android:layout_height="50dp"
        android:orientation="vertical"
        android:focusable="true"
        android:focusableInTouchMode="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintWidth_percent="0.9"
        app:layout_constraintHorizontal_bias="0.25">
        <View
            android:id="@+id/view"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:background="@color/colorAccent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"/>
        </android.support.constraint.ConstraintLayout>

</android.support.constraint.ConstraintLayout>

https://developer.android.com/reference/androidx/constraintlayout/widget/ConstraintLayout#Bias