Question

10.2. layout

		
<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />


    <Button
        android:id="@+id/buttonOpenCamera"
        android:layout_width="160dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:text="拍照立即显示"
        app:layout_constraintBottom_toTopOf="@+id/buttonAlbum"
        app:layout_constraintEnd_toStartOf="@+id/buttonSavePhoto"
        app:layout_constraintHorizontal_bias="0.283"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageViewPicture"
        app:layout_constraintVertical_bias="0.0" />

    <Button
        android:id="@+id/buttonSavePhoto"
        android:layout_width="160dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="20dp"
        android:layout_marginBottom="8dp"
        android:text="拍照存储后显示"
        app:layout_constraintBottom_toTopOf="@+id/buttonAlbum"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageViewPicture"
        app:layout_constraintVertical_bias="0.0" />

    <ImageView
        android:id="@+id/imageViewPicture"
        android:layout_width="338dp"
        android:layout_height="366dp"
        android:layout_centerHorizontal="true"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <Button
        android:id="@+id/buttonAlbum"
        android:layout_width="352dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:text="Album"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />


</android.support.constraint.ConstraintLayout>