android:用ConstraintLayout布局一个计算器

一，常用属性:

常用属性：

layout_constraintLeft_toLeftOf：左边和目标组件的左边对齐
layout_constraintLeft_toRightOf：左边和目标组件的右边对齐
layout_constraintRight_toLeftOf：右边和目标组件的左边对齐
layout_constraintRight_toRightOf：右边和目标组件的右边对齐
layout_constraintTop_toTopOf：上边和目标组件的上边对齐
layout_constraintTop_toBottomOf：上边和目标组件的下边对齐
layout_constraintBottom_toTopOf：下边和目标组件的上边对齐
layout_constraintBottom_toBottomOf：下边和目标组件的下边对齐
layout_constraintBaseline_toBaselineOf：文本基线对齐，如两个TextView的高度不一致，但是又希望他们文本对齐
layout_constraintStart_toStartOf：同layout_constraintLeft_toLeftOf
layout_constraintStart_toEndOf：同layout_constraintLeft_toRightOf
layout_constraintEnd_toStartOf：同layout_constraintRight_toLeftOf
layout_constraintEnd_toEndOf：同layout_constraintRight_toRightOf
layout_constraintHorizontal_bias：左右约束时的水平偏移量，可设置0-1的数值，默认0.5居中
layout_constraintVertical_bias：上下约束时的垂直偏移量，可设置0-1的数值，默认0.5居中
layout_constraintHorizontal_weight：水平权重值，可以是任意数值，在0dp时生效
layout_constraintVertical_weight：垂直权重，可以是任意数值，在0dp时生效
layout_constraintDimensionRatio：宽高比，当宽或高至少有一个尺寸被设置为0dp时可设置比例，如（1:2）

二，代码：

xml

activity

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".activity.ConstraintActivity">


    <TextView
        android:id="@+id/c_view1"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_gravity="fill"
        android:gravity="end"
        android:layout_marginStart="5dp"
        android:layout_marginEnd="5dp"
        android:layout_marginTop="5dp"
        android:background="#FFCCCC"
        android:text="0"
        android:textSize="50sp" />
    <Button
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        app:layout_constraintTop_toBottomOf="@id/c_view1"
        app:layout_constraintStart_toStartOf="@id/c_view1"
        app:layout_constraintEnd_toStartOf="@id/btn_qk"
        android:layout_marginStart="5dp"
        android:layout_marginEnd="5dp"
        android:layout_marginTop="5dp"
        android:textSize="40sp"
        android:id="@+id/btn_ht"
        android:text="回退" />
    <Button
        android:id="@+id/btn_qk"
        android:layout_height="0dp"
        android:layout_width="0dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        app:layout_constraintEnd_toEndOf="@id/c_view1"
        app:layout_constraintStart_toEndOf="@id/btn_ht"
        app:layout_constraintTop_toBottomOf="@id/c_view1"
        app:layout_constraintBottom_toBottomOf="@id/btn_ht"
        android:layout_marginStart="5dp"
        android:layout_marginEnd="5dp"
        android:layout_marginTop="5dp"
        android:textSize="40sp"
        android:text="清空" />

    <Button android:text="+"
        android:id="@+id/btn_jia"
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:layout_marginEnd="5dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        android:layout_marginTop="5dp"
        app:layout_constraintHorizontal_weight="1"
        app:layout_constraintTop_toBottomOf="@id/btn_ht"
        app:layout_constraintStart_toStartOf="@id/btn_ht"
        app:layout_constraintEnd_toStartOf="@id/btn_01"
        />
    <Button android:text="1"
        android:id="@+id/btn_01"
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:layout_marginEnd="5dp"
        android:layout_marginStart="5dp"
        android:layout_marginTop="5dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        app:layout_constraintHorizontal_weight="1"
        app:layout_constraintTop_toBottomOf="@id/btn_ht"
        app:layout_constraintStart_toEndOf="@id/btn_jia"
        app:layout_constraintEnd_toStartOf="@id/btn_02"
        />
    <Button android:text="2"
        android:id="@+id/btn_02"
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:layout_marginEnd="5dp"
        android:layout_marginStart="5dp"
        android:layout_marginTop="5dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        app:layout_constraintHorizontal_weight="1"
        app:layout_constraintTop_toBottomOf="@id/btn_ht"
        app:layout_constraintStart_toEndOf="@id/btn_01"
        app:layout_constraintEnd_toStartOf="@id/btn_03"
        />
    <Button android:text="3"
        android:id="@+id/btn_03"
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        android:layout_marginStart="5dp"
        android:layout_marginTop="5dp"
        app:layout_constraintHorizontal_weight="1"
        app:layout_constraintTop_toBottomOf="@id/btn_ht"
        app:layout_constraintStart_toEndOf="@id/btn_02"
        app:layout_constraintEnd_toEndOf="@id/btn_qk"
        />
    <Button android:text="-"
        android:id="@+id/btn_jian"
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:layout_marginEnd="5dp"
        android:layout_marginTop="5dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        app:layout_constraintHorizontal_weight="1"
        app:layout_constraintTop_toBottomOf="@id/btn_jia"
        app:layout_constraintStart_toStartOf="@id/btn_ht"
        app:layout_constraintEnd_toStartOf="@id/btn_04"
        />
    <Button android:text="4"
        android:id="@+id/btn_04"
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:layout_marginEnd="5dp"
        android:layout_marginStart="5dp"
        android:layout_marginTop="5dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        app:layout_constraintHorizontal_weight="1"
        app:layout_constraintTop_toBottomOf="@id/btn_jia"
        app:layout_constraintEnd_toStartOf="@id/btn_05"
        app:layout_constraintStart_toEndOf="@id/btn_jian"
        />
    <Button android:text="5"
        android:id="@+id/btn_05"
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:layout_marginEnd="5dp"
        android:layout_marginStart="5dp"
        android:layout_marginTop="5dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        app:layout_constraintHorizontal_weight="1"
        app:layout_constraintTop_toBottomOf="@id/btn_jia"
        app:layout_constraintEnd_toStartOf="@id/btn_06"
        app:layout_constraintStart_toEndOf="@id/btn_04"
        />
    <Button android:text="6"
        android:id="@+id/btn_06"
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:layout_marginStart="5dp"
        android:layout_marginTop="5dp"
        android:background="@drawable/rounded_corner"
        android:textColor="#ffffff"
        app:layout_constraintHorizontal_weight="1"
        app:layout_constraintTop_toBottomOf="@id/btn_jia"
        app:layout_constraintStart_toEndOf="@id/btn_05"
        app:layout_constraintEnd_toEndOf="@id/btn_qk"
        />



</androidx.constraintlayout.widget.ConstraintLayout>

rounded_corner.xml

起到圆角作用

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <corners android:radius="10dp" />
    <solid android:color="#006400" />
</shape>

三，测试效果