Android progressbar in swipe layout invisible

Question

In one layout file I want show a progressbar and a swipeable webview. If I implement the swipe layout the progressbar disappears automatically and can't be shown.

What's the problem?

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:mlns="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.xy.MainActivity">

    <ProgressBar
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/progressBarCenter"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true"
    android:visibility="visible"
    android:background="#ff0303" />

<android.support.v4.widget.SwipeRefreshLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:mlns="http://schemas.android.com/apk/res-auto"
    android:id="@+id/swiper"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.xy.MainActivity">

    <WebView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/webView"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />
</android.support.v4.widget.SwipeRefreshLayout>
</RelativeLayout>

Answer 1

It is because SwipeRefreshLayout is covering ProgressBar. In RelativeLayout, the one at lower down in the Xml means higher up in the Z-axis.

Reverse the order should work.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:mlns="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.xy.MainActivity">

    <android.support.v4.widget.SwipeRefreshLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:mlns="http://schemas.android.com/apk/res-auto"
        android:id="@+id/swiper"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context="com.xy.MainActivity">

        <WebView
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:id="@+id/webView"
            android:layout_alignParentTop="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true" />
    </android.support.v4.widget.SwipeRefreshLayout>

    <ProgressBar
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/progressBarCenter"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:visibility="visible"
        android:background="#ff0303" />
</RelativeLayout>