ConstraintLayout使用实战

实战演示效果

性能优势:

Android系统在绘制控件的时候，会经过测量，布局，绘制三个过程，每个过程都会自顶向下遍历视图树。所以布局嵌套层次越深，设备绘制视图所需的时间和计算功耗也就越多。 ConstraintLayout 容器就是用来构建复杂布局的，而不必嵌套 View 和 ViewGroup 元素，实现完全扁平的层次结构。

自顶向下绘制过程图

使用介绍：

• 相对定位

layout_constraintLeft_toLeftOf
layout_constraintLeft_toRightOf
layout_constraintRight_toLeftOf
layout_constraintRight_toRightOf
layout_constraintTop_toTopOf
layout_constraintTop_toBottomOf
layout_constraintBottom_toTopOf
layout_constraintBottom_toBottomOf
layout_constraintBaseline_toBaselineOf
layout_constraintStart_toEndOf
layout_constraintStart_toStartOf
layout_constraintEnd_toStartOf
layout_constraintEnd_toEndOf

效果类似于RelativeLayout的相对定位使用效果，以上属性需要另一个控件的id或parent作为参考。

• Guideline

Guideline是只能用在ConstraintLayout布局里面的一个工具类，用于辅助布局，类似为辅助线，主要作用是将该页面的控件统一设置左侧对齐或右侧对齐。Guideline是不会显示到界面上的，默认是GONE的。

layout_constraintGuide_begin
layout_constraintGuide_end
layout_constraintGuide_percent

• 居中定位

layout_constraintLeft_toLeftOf
layout_constraintRight_toRightOf

同时设置同一控件id即可与该控件居中对齐。

• 偏压

layout_constraintHorizontal_bias
layout_constraintVertical_bias

在居中对齐的基础上，设置居于垂直或水品位置的比例。

• 圆形定位

layout_constraintCircle ：依赖哪个控件进行布局
layout_constraintCircleRadius ：到依赖对象中心的距离
layout_constraintCircleAngle ：当前要摆放的控件应处于哪个角度

• 尺寸限制

android:minWidth 设置布局的最小宽度
android:minHeight 设置布局的最小高度
android:maxWidth 设置布局的最大宽度
android:maxHeight 设置布局的最大高度

要设置尺寸限制，需要在宽高都设为wrap_content才能生效。

• Ratio比例

layout_constraintDimensionRatio
可设定该控件通过宽高比或者高宽比来限定控件的比例。

• Chains链

设置一条线上布局的对齐属性。

• Group

Group 用于控制所引用的一组控件的可见性。用如下属性来设置多个控件id，通过对自己的可见性改变统一改变这些控件的可见性。

constraint_referenced_ids

• Placeholder

通过设置app:content=“id”，将id View的内容绘制到自己的位置上，而原id的 View就像gone了一样。

这里是代码地址

布局文件代码：

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context=".MineActivity">

    <androidx.core.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <androidx.constraintlayout.widget.Guideline
                android:id="@+id/guideline_left"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                app:layout_constraintGuide_begin="15dp"/>

            <androidx.constraintlayout.widget.Guideline
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                app:layout_constraintGuide_begin="27dp"/>

            <androidx.constraintlayout.widget.Guideline
                android:id="@+id/guideline_right"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                app:layout_constraintGuide_end="15dp"/>

            <View
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:background="@color/orange2"
                app:layout_constraintDimensionRatio="100:35"
                app:layout_constraintTop_toTopOf="parent" />

            <ImageView
                android:id="@+id/iv_scan"
                android:layout_width="50dp"
                android:layout_height="50dp"
                android:src="@mipmap/scan"
                android:padding="14dp"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintTop_toTopOf="parent"/>

            <ImageView
                android:id="@+id/iv_edit"
                android:layout_width="50dp"
                android:layout_height="50dp"
                android:src="@mipmap/edit"
                android:padding="14dp"
                app:layout_constraintRight_toRightOf="parent"
                app:layout_constraintTop_toTopOf="parent"/>

            <androidx.constraintlayout.widget.ConstraintLayout
                android:id="@+id/login_box"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:paddingLeft="12dp"
                android:paddingRight="12dp"
                android:paddingTop="12dp"
                android:paddingBottom="20dp"
                android:elevation="2dp"
                android:background="@drawable/shape_round_white"
                app:layout_constraintTop_toBottomOf="@id/iv_edit"
                android:layout_margin="15dp">

                <ImageView
                    android:id="@+id/iv_head"
                    android:layout_width="60dp"
                    android:layout_height="60dp"
                    android:layout_marginTop="13dp"
                    android:background="@mipmap/default_head"
                    app:layout_constraintTop_toTopOf="parent"
                    app:layout_constraintLeft_toLeftOf="parent" />

                <TextView
                    android:id="@+id/tv_login"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="点击登录"
                    android:textSize="18sp"
                    android:textColor="@color/black"
                    app:layout_constraintLeft_toRightOf="@id/iv_head"
                    app:layout_constraintTop_toTopOf="@id/iv_head"
                    android:layout_marginLeft="10dp"
                    android:layout_marginTop="5dp"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="成就你的写作梦想"
                    android:maxWidth="200dp"
                    android:textSize="12sp"
                    app:layout_constraintBottom_toBottomOf="@id/iv_head"
                    app:layout_constraintLeft_toLeftOf="@id/tv_login"
                    android:layout_marginBottom="5dp"/>

                <ImageView
                    android:id="@+id/iv_gift"
                    android:layout_width="35dp"
                    android:layout_height="35dp"
                    android:background="@mipmap/gift"
                    app:layout_constraintVertical_bias="0.12"
                    app:layout_constraintTop_toTopOf="parent"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintRight_toRightOf="parent"
                    android:layout_marginRight="8dp"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="免费领"
                    android:textSize="8sp"
                    android:paddingLeft="8dp"
                    android:paddingRight="8dp"
                    android:paddingTop="1dp"
                    android:paddingBottom="1dp"
                    app:layout_constraintLeft_toLeftOf="@id/iv_gift"
                    app:layout_constraintRight_toRightOf="@id/iv_gift"
                    app:layout_constraintTop_toBottomOf="@id/iv_gift"
                    android:background="@drawable/shape_roung_perple"
                    android:textColor="@color/white"/>

                <View
                    android:id="@+id/view_line"
                    android:layout_width="match_parent"
                    android:layout_height="1dp"
                    android:background="@color/light_gray"
                    app:layout_constraintTop_toBottomOf="@id/iv_head"
                    android:layout_marginTop="10dp"
                    android:layout_marginBottom="10dp"/>

                <ImageView
                    android:id="@+id/iv_ic1"
                    android:layout_width="30dp"
                    android:layout_height="30dp"
                    android:background="@mipmap/pic1"
                    android:layout_marginTop="14dp"
                    android:layout_marginLeft="20dp"
                    app:layout_constraintHorizontal_chainStyle="spread_inside"
                    app:layout_constraintLeft_toLeftOf="parent"
                    app:layout_constraintRight_toLeftOf="@id/iv_ic2"
                    app:layout_constraintTop_toTopOf="@id/view_line"/>

                <TextView
                    android:id="@+id/tv_my_artical"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="我的文章"
                    android:textColor="@color/black"
                    android:layout_marginTop="12dp"
                    app:layout_constraintTop_toBottomOf="@id/iv_ic1"
                    app:layout_constraintLeft_toLeftOf="@id/iv_ic1"
                    app:layout_constraintRight_toRightOf="@id/iv_ic1"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="0篇私密"
                    android:layout_marginTop="5dp"
                    android:textSize="11sp"
                    app:layout_constraintTop_toBottomOf="@id/tv_my_artical"
                    app:layout_constraintLeft_toLeftOf="@id/iv_ic1"
                    app:layout_constraintRight_toRightOf="@id/iv_ic1"/>

                <ImageView
                    android:id="@+id/iv_ic2"
                    android:layout_width="30dp"
                    android:layout_height="30dp"
                    android:background="@mipmap/pic2"
                    android:layout_marginTop="14dp"
                    app:layout_constraintLeft_toRightOf="@id/iv_ic1"
                    app:layout_constraintRight_toLeftOf="@id/iv_ic3"
                    app:layout_constraintTop_toTopOf="@id/view_line"/>

                <TextView
                    android:id="@+id/tv_my_sticker"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="我的帖子"
                    android:layout_marginTop="12dp"
                    android:textColor="@color/black"
                    app:layout_constraintTop_toBottomOf="@id/iv_ic2"
                    app:layout_constraintLeft_toLeftOf="@id/iv_ic2"
                    app:layout_constraintRight_toRightOf="@id/iv_ic2"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="0个帖子"
                    android:layout_marginTop="5dp"
                    android:textSize="11sp"
                    app:layout_constraintTop_toBottomOf="@id/tv_my_sticker"
                    app:layout_constraintLeft_toLeftOf="@id/iv_ic2"
                    app:layout_constraintRight_toRightOf="@id/iv_ic2"/>

                <ImageView
                    android:id="@+id/iv_ic3"
                    android:layout_width="30dp"
                    android:layout_height="30dp"
                    android:background="@mipmap/pic3"
                    android:layout_marginTop="14dp"
                    app:layout_constraintLeft_toRightOf="@id/iv_ic2"
                    app:layout_constraintRight_toLeftOf="@id/iv_ic4"
                    app:layout_constraintTop_toTopOf="@id/view_line"/>

                <TextView
                    android:id="@+id/tv_like"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="赞和收藏"
                    android:layout_marginTop="12dp"
                    android:textColor="@color/black"
                    app:layout_constraintTop_toBottomOf="@id/iv_ic3"
                    app:layout_constraintLeft_toLeftOf="@id/iv_ic3"
                    app:layout_constraintRight_toRightOf="@id/iv_ic3"/>

                <ImageView
                    android:id="@+id/iv_ic4"
                    android:layout_width="30dp"
                    android:layout_height="30dp"
                    android:background="@mipmap/pic4"
                    android:layout_marginTop="14dp"
                    android:layout_marginRight="20dp"
                    app:layout_constraintLeft_toRightOf="@id/iv_ic3"
                    app:layout_constraintRight_toRightOf="parent"
                    app:layout_constraintTop_toTopOf="@id/view_line"/>

                <TextView
                    android:id="@+id/tv_my_book"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="赞和收藏"
                    android:layout_marginTop="12dp"
                    android:textColor="@color/black"
                    app:layout_constraintTop_toBottomOf="@id/iv_ic4"
                    app:layout_constraintLeft_toLeftOf="@id/iv_ic4"
                    app:layout_constraintRight_toRightOf="@id/iv_ic4"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="含已购内容"
                    android:layout_marginTop="5dp"
                    android:textSize="11sp"
                    app:layout_constraintTop_toBottomOf="@id/tv_my_book"
                    app:layout_constraintLeft_toLeftOf="@id/iv_ic4"
                    app:layout_constraintRight_toRightOf="@id/iv_ic4"/>
            </androidx.constraintlayout.widget.ConstraintLayout>

            <androidx.constraintlayout.widget.ConstraintLayout
                android:id="@+id/menu"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@drawable/shape_round_white"
                app:layout_constraintTop_toBottomOf="@id/login_box"
                android:layout_margin="15dp"
                android:elevation="2dp"
                android:padding="12dp">

                <androidx.constraintlayout.widget.Group
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    app:constraint_referenced_ids="tv_assets,tv_check,view_line2"/>

                <TextView
                    android:id="@+id/tv_assets"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="总资产：0"
                    android:textColor="@color/black"
                    app:layout_constraintLeft_toLeftOf="parent"
                    app:layout_constraintTop_toTopOf="parent"/>

                <TextView
                    android:id="@+id/tv_check"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="查看"
                    android:textSize="12sp"
                    android:gravity="center_vertical"
                    android:drawableRight="@mipmap/arrow_right"
                    app:layout_constraintRight_toRightOf="parent"
                    app:layout_constraintTop_toTopOf="parent"
                    android:drawablePadding="8dp"/>

                <View
                    android:id="@+id/view_line2"
                    android:layout_width="match_parent"
                    android:layout_height="1dp"
                    android:background="@color/light_gray"
                    app:layout_constraintTop_toBottomOf="@id/tv_assets"
                    android:layout_marginTop="10dp"
                    android:layout_marginBottom="10dp"/>

                <ImageView
                    android:id="@+id/iv_dimends"
                    android:layout_width="30dp"
                    android:layout_height="30dp"
                    android:background="@mipmap/dimends"
                    app:layout_constraintTop_toTopOf="@id/view_line2"
                    app:layout_constraintLeft_toLeftOf="parent"
                    app:layout_constraintRight_toLeftOf="@id/iv_vip"
                    android:layout_marginLeft="15dp"
                    app:layout_constraintHorizontal_chainStyle="spread_inside"
                    android:layout_marginTop="15dp"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="@color/black"
                    android:text="简书钻"
                    app:layout_constraintLeft_toLeftOf="@id/iv_dimends"
                    app:layout_constraintRight_toRightOf="@id/iv_dimends"
                    app:layout_constraintTop_toBottomOf="@id/iv_dimends"
                    android:layout_marginTop="8dp"/>

                <ImageView
                    android:id="@+id/iv_vip"
                    android:layout_width="30dp"
                    android:layout_height="30dp"
                    android:background="@mipmap/vip"
                    app:layout_constraintTop_toTopOf="@id/view_line2"
                    app:layout_constraintLeft_toRightOf="@id/iv_dimends"
                    app:layout_constraintRight_toLeftOf="@id/iv_prize"
                    android:layout_marginTop="15dp"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="@color/black"
                    android:text="简书会员"
                    app:layout_constraintLeft_toLeftOf="@id/iv_vip"
                    app:layout_constraintRight_toRightOf="@id/iv_vip"
                    app:layout_constraintTop_toBottomOf="@id/iv_vip"
                    android:layout_marginTop="8dp"/>

                <ImageView
                    android:id="@+id/iv_prize"
                    android:layout_width="30dp"
                    android:layout_height="30dp"
                    android:background="@mipmap/prize"
                    app:layout_constraintTop_toTopOf="@id/view_line2"
                    app:layout_constraintLeft_toRightOf="@id/iv_vip"
                    app:layout_constraintRight_toLeftOf="@id/iv_rank"
                    android:layout_marginTop="15dp"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="@color/black"
                    android:text="天天抽奖"
                    app:layout_constraintLeft_toLeftOf="@id/iv_prize"
                    app:layout_constraintRight_toRightOf="@id/iv_prize"
                    app:layout_constraintTop_toBottomOf="@id/iv_prize"
                    android:layout_marginTop="8dp"/>

                <ImageView
                    android:id="@+id/iv_rank"
                    android:layout_width="30dp"
                    android:layout_height="30dp"
                    android:background="@mipmap/rank"
                    app:layout_constraintTop_toTopOf="@id/view_line2"
                    app:layout_constraintLeft_toRightOf="@id/iv_prize"
                    app:layout_constraintRight_toRightOf="parent"
                    android:layout_marginRight="15dp"
                    android:layout_marginTop="15dp"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="@color/black"
                    android:text="排行榜"
                    app:layout_constraintLeft_toLeftOf="@id/iv_rank"
                    app:layout_constraintRight_toRightOf="@id/iv_rank"
                    app:layout_constraintTop_toBottomOf="@id/iv_rank"
                    android:layout_marginTop="8dp"/>
            </androidx.constraintlayout.widget.ConstraintLayout>

            <View
                android:id="@+id/view_topline"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                app:layout_constraintTop_toBottomOf="@id/menu"
                android:layout_marginTop="10dp"/>

            <View
                android:id="@+id/view_line3"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                app:layout_constraintTop_toBottomOf="@id/view_topline"
                android:layout_marginTop="48dp"/>

            <View
                android:id="@+id/view_line4"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                app:layout_constraintTop_toBottomOf="@id/view_line3"
                android:layout_marginTop="48dp"/>

            <View
                android:id="@+id/view_line5"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                app:layout_constraintTop_toBottomOf="@id/view_line4"
                android:layout_marginTop="48dp"/>

            <View
                android:id="@+id/view_line6"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                app:layout_constraintTop_toBottomOf="@id/view_line5"
                android:layout_marginTop="48dp"/>

            <View
                android:id="@+id/view_line7"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                app:layout_constraintTop_toBottomOf="@id/view_line6"
                android:layout_marginTop="48dp"/>

            <View
                android:id="@+id/view_line8"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                app:layout_constraintTop_toBottomOf="@id/view_line7"
                android:layout_marginTop="48dp"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="我的钱包"
                android:textSize="15sp"
                android:textColor="@color/black"
                app:layout_constraintTop_toTopOf="@id/view_topline"
                app:layout_constraintBottom_toBottomOf="@id/view_line3"
                app:layout_constraintLeft_toLeftOf="@id/guideline_left"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="我的优惠券"
                app:layout_constraintTop_toTopOf="@id/view_topline"
                app:layout_constraintBottom_toBottomOf="@id/view_line3"
                app:layout_constraintRight_toRightOf="@id/guideline_right"
                android:drawableRight="@mipmap/arrow_right"
                android:drawablePadding="10dp"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="简书活动"
                android:textSize="15sp"
                android:textColor="@color/black"
                app:layout_constraintTop_toTopOf="@id/view_line3"
                app:layout_constraintBottom_toBottomOf="@id/view_line4"
                app:layout_constraintLeft_toLeftOf="@id/guideline_left"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                app:layout_constraintTop_toTopOf="@id/view_line3"
                app:layout_constraintBottom_toBottomOf="@id/view_line4"
                app:layout_constraintRight_toRightOf="@id/guideline_right"
                android:drawableRight="@mipmap/arrow_right"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="我的小岛/专题/文集"
                android:textSize="15sp"
                android:textColor="@color/black"
                app:layout_constraintTop_toTopOf="@id/view_line4"
                app:layout_constraintBottom_toBottomOf="@id/view_line5"
                app:layout_constraintLeft_toLeftOf="@id/guideline_left"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                app:layout_constraintTop_toTopOf="@id/view_line4"
                app:layout_constraintBottom_toBottomOf="@id/view_line5"
                app:layout_constraintRight_toRightOf="@id/guideline_right"
                android:drawableRight="@mipmap/arrow_right"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="浏览历史"
                android:textSize="15sp"
                android:textColor="@color/black"
                app:layout_constraintTop_toTopOf="@id/view_line5"
                app:layout_constraintBottom_toBottomOf="@id/view_line6"
                app:layout_constraintLeft_toLeftOf="@id/guideline_left"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                app:layout_constraintTop_toTopOf="@id/view_line5"
                app:layout_constraintBottom_toBottomOf="@id/view_line6"
                app:layout_constraintRight_toRightOf="@id/guideline_right"
                android:drawableRight="@mipmap/arrow_right"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="意见反馈"
                android:textSize="15sp"
                android:textColor="@color/black"
                app:layout_constraintTop_toTopOf="@id/view_line6"
                app:layout_constraintBottom_toBottomOf="@id/view_line7"
                app:layout_constraintLeft_toLeftOf="@id/guideline_left"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                app:layout_constraintTop_toTopOf="@id/view_line6"
                app:layout_constraintBottom_toBottomOf="@id/view_line7"
                app:layout_constraintRight_toRightOf="@id/guideline_right"
                android:drawableRight="@mipmap/arrow_right"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="设置"
                android:textSize="15sp"
                android:textColor="@color/black"
                app:layout_constraintTop_toTopOf="@id/view_line7"
                app:layout_constraintBottom_toBottomOf="@id/view_line8"
                app:layout_constraintLeft_toLeftOf="@id/guideline_left"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                app:layout_constraintTop_toTopOf="@id/view_line7"
                app:layout_constraintBottom_toBottomOf="@id/view_line8"
                app:layout_constraintRight_toRightOf="@id/guideline_right"
                android:drawableRight="@mipmap/arrow_right"/>


        </androidx.constraintlayout.widget.ConstraintLayout>

    </androidx.core.widget.NestedScrollView>

</androidx.constraintlayout.widget.ConstraintLayout>