[Android development] Constraint layout

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:background="@mipmap/bg1">

    <!--
        app:layout_constraint方位_to方位Of="?"
        ?  : 1. parent    2.引用其他控件id

        当前控件的某个方位和另一个参照物的某个方位对齐
        app:layout_constraintLeft_toLeftOf  相当于RelativeLayout的alignLeft属性
        app:layout_constraintRight_toRightOf 相当于RelativeLayout的alignRight属性
        app:layout_constraintTop_toTopOf    相当于RelativeLayout的alignTop属性
        app:layout_constraintBottom_toBottomOf  相当于RelativeLayout的alignBottom属性
        app:layout_constraintStart_toStartOf    同Left_toLeftOf
        app:layout_constraintEnd_toEndOf    同Right_toRightOf

        当前控件的A侧会在参照物的B侧
        app:layout_constraintLeft_toRightOf    相当于RelativeLayout的toRightOf
        app:layout_constraintRight_toLeftOf    相当于RelativeLayout的toLeftOf
        app:layout_constraintTop_toBottomOf    相当于RelativeLayout的below
        app:layout_constraintBottom_toTopOf    相当于RelativeLayout的above
        app:layout_constraintStart_toEndOf     同Left_toRightOf
        app:layout_constraintEnd_toStartOf      同Right_toLeftOf


        app:layout_constraintVertical_bias="0.53"     垂直偏移量，0.5在正中间
        app:layout_constraintHorizontal_bias="0.53"     水平偏移量，0.5在正中间
    -->

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="红包"
        android:textColor="#f6d5a8"
        android:textSize="22sp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="15dp"
        android:text="&lt; 返回"
        android:textColor="#f6d5a8"
        android:textSize="22sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:text="红包记录"
        android:textColor="#f6d5a8"
        android:textSize="22sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button"
        android:layout_width="330dp"
        android:layout_height="50dp"
        android:background="@mipmap/btn1"
        android:text="一字千金红包"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.53" />

    <Button
        android:id="@+id/button1"
        android:layout_width="330dp"
        android:layout_height="50dp"
        android:layout_marginBottom="20dp"
        android:background="@mipmap/btn1"
        android:text="普通红包"
        app:layout_constraintBottom_toTopOf="@id/button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <Button
        android:id="@+id/button2"
        android:layout_width="330dp"
        android:layout_height="50dp"
        android:layout_marginBottom="20dp"
        android:background="@mipmap/btn1"
        android:text="口令红包"
        app:layout_constraintBottom_toTopOf="@+id/button1"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <LinearLayout
        android:id="@+id/linearLayout"
        android:layout_width="330dp"
        android:layout_height="60dp"
        android:background="@mipmap/edit"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button"
        app:layout_constraintVertical_bias="0.39">

        <EditText
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:background="@null"
            android:gravity="center"
            android:hint="输口令，领红包"
            android:textColorHint="#f6D5A8" />

        <TextView
            android:layout_width="90dp"
            android:layout_height="match_parent"
            android:gravity="center"
            android:text="确定"
            android:textColor="#cccccc"
            android:textSize="26sp" />
    </LinearLayout>

    <TextView
        android:id="@+id/textView5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:text="口令红包规则"
        android:textColor="#f6D5A8"
        android:textSize="18sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/linearLayout" />

</androidx.constraintlayout.widget.ConstraintLayout>