activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="xmlpull.sample.jean.xmlpull.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="嘉義市空氣品質狀況"
        android:id="@+id/tv_city"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="PM2.5數值："
        android:id="@+id/tv_pm25"
        android:layout_below="@+id/tv_city"
        android:layout_alignParentStart="true"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:id="@+id/tv_val_pm25"
        android:layout_alignTop="@+id/tv_pm25"
        android:layout_toEndOf="@+id/tv_pm25"
        android:text="N/A" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="資料更新時間："
        android:id="@+id/textView"
        android:layout_below="@+id/tv_pm25"
        android:layout_alignParentStart="true"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="xxxx-xx-xx xx:xx"
        android:id="@+id/tv_val_time"
        android:layout_below="@+id/tv_pm25"
        android:layout_toEndOf="@+id/textView"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="更新"
        android:id="@+id/button_update"
        android:layout_below="@+id/textView"
        android:layout_alignParentStart="true"/>

</RelativeLayout>