[안드로이드 스튜디오] XML 파일로 사용자 인터페이스 작성

1. new project -> empty 뭐시기 -> 제목 : button 뭐시기

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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">

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:text="첫번째 버튼"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"></Button>

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:text="두번째 버튼"
        app:layout_constraintStart_toStartOf="@+id/button1"
        app:layout_constraintTop_toBottomOf="@+id/button1"></Button>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat
    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"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="첫번째 버튼">
    </Button>

    <Button
        android:id="@+id/button2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="두번째 버튼">
    </Button>
</androidx.appcompat.widget.LinearLayoutCompat>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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"
    android:orientation="vertical"
    android:background="#aaff0000"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button1"
        android:layout_width="250dp"
        android:layout_height="60dp"
        android:layout_margin="30dp"
        android:padding="10dp"
        android:background="#8BC34A"
        android:text="마진 30dp, 패딩 10dp">
    </Button>

    <Button
        android:id="@+id/button2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#aa223400"
        android:text="두번째 버튼"
        android:enabled="false">
    </Button>

    <Button
        android:id="@+id/button3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="세번째 버튼">
    </Button>

    <Button
        android:id="@+id/button4"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:rotation="45"
        android:text="네번째 버튼">
    </Button>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:backgroundTint="#ffff00"
        android:text="첫번째 버튼"
        android:textColor="#00aa00"
        android:textSize="30dp">
    </Button>

    <Button
        android:id="@+id/button2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#aa223400"
        android:text="두번째 버튼">
    </Button>

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        android:text="나는 텍스트뷰입니다."
        android:textColor="#ff0000"
        android:gravity="center">
    </TextView>

</LinearLayout>