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backgroundTint in XML does not change color of BottomActionBar, even with min API >= 21

I'm trying to set up a basic BottomActionBar with an attached FloatingActionButton. Currently, everything seems to work, aside from the background of the bar. If I use android:background="some_background_color", the bar is filled in with the desired color.
The problem is that I want my FAB to be cradled, and this approach seems to be incompatible with fabCradleMargin and fabCradleRoundedCornerRadius, as the background bar is unaffected by modifying these values.
All tutorials indicate that app:backgroundTint="some_background_color" is the way to go, but my action bar remains unaffected by this. I've set my API to >= 21, so as far as I know, there are no issues there.
My XML file:
<?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">
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent">
<com.google.android.material.bottomappbar.BottomAppBar
android:id="#+id/bottom_app_bar"
style="#style/Widget.MaterialComponents.BottomAppBar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:backgroundTint="#color/colorPrimary"
app:fabAlignmentMode="center"
app:fabAttached="true"
app:fabCradleMargin="10dp"
app:fabCradleRoundedCornerRadius="10dp" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_add_white_24dp"
app:layout_anchor="#+id/bottom_app_bar"
app:layout_anchorGravity="center_horizontal"
app:fabSize="normal"/>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
The backgroundTint has no effect on the bar; it remains completely white.
Sorry if this is an elementary question; I'm quite new to Android and have spent quite a while searching for a solution to no avail.

I tested your code
it shows an error for BottomAppBar so I findout this code app:fabAttached="true" is Undefined...
remove it and it will work perfectly.
Goodluck.

Android PDF scrollview single continuous page

In xcode I can display a PDF as a single continuous page, with the PDF width being equal to screen width and then the vertical scroll being the height of PDF for said width. No problems
Currently converting same app to Android and having some difficulty implementing same PDF view
Basically I have a PDF page that is very long (single page). I don't want to swipe between pages, but instead like in my iOS app, have the PDF document fill the Android screen width wise, and then scroll vertically to show rest of PDF
I'm using com.github.barteksc.pdfviewer.PDFView to render my PDF
In my xml for the activity I have:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView 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:fillViewport="true">
tools:context=".ProfileActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.github.barteksc.pdfviewer.PDFView
android:id="#+id/pdfView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
</ScrollView>
I've tried changing the layout_height to "wrap_content" for scrollView, Linear and pdf, as that would seem appropriate, but whenever I do this I get a blank screen. It seems that doing so resulting in no height attribute so the view collapses completely
I get:
What I want:
Would really appreciate any further help, this is really my only sticking point. I wish android had PDFKit (similar) as I found that quite easy to use and implement

Well there is an answer!
I had to 'upgrade' to the latest version: 3.1.0-beta.1 and use the:
.pageFitPolicy(FitPolicy.WIDTH)
Combined with my XML:
<ScrollView 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:fillViewport="true">
tools:context=".AboutActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:orientation="vertical">
<com.github.barteksc.pdfviewer.PDFView
android:id="#+id/pdfView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
</ScrollView>
Worked perfectly. I hope this helps others

OSMdroid how to add watermark

I'm creating an free Android application and I'm using OpenStreetMap (OSMdroid library). I have a question. On the webpage: https://www.openstreetmap.org/copyright
I have read, that I should put a text in the corner of map activity (#OpenStreetMap contributors).
How to do this?
I'd like my app to be comply with the OSM license.
Regards

There is a built in copyright overlay for displaying the notice based on the current tile source.
Edit, sample code is below
//Copyright overlay
mCopyrightOverlay = new CopyrightOverlay(context);
mMapView.getOverlays().add(this.mCopyrightOverlay);
Basically, whatever the current tile source is, the text overlay will be drawn.

When you have your layout file simply add a TextView with "#OpenStreetMap contributors" to it. (I recommend to use a RelativeLayout)
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<org.osmdroid.views.MapView android:id="#+id/map"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:text="OpenStreetMap Contributors" />
</RelativeLayout>
I saw in other apps that on startup they all show this and a few seconds later it is fading out so you can use a delayed animation for that.
textView.animate().setStartDelay(3000).alpha(0).setDuration(1000).start();

Can't get imageview to sit flush with the top of the screen

I'm trying to place an image view at the top of the screen, but it has some type of margin above and below it. So I tried adjustViewBounds = true, and it worked but then it wouldn't reach the sides of the screen. I just want it to be flush with the top of the screen, and reach the sides. Any suggestions?
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="match_parent"
tools:context="${packageName}.${activityClass}"
android:orientation="vertical" >
<ImageView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="#drawable/title_bar"/>
<ScrollView
android:id="#+id/scrollView1"
android:layout_width="fill_parent"
android:layout_height="200dp" >
<LinearLayout
android:id="#+id/goals"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:orientation="vertical" >
</LinearLayout>
</ScrollView>
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:background="#android:color/black" >
</RelativeLayout>

If it is just colored title bar - then it is make sense to use just View for example and set background property to needed color. If You have custom image for that and can not adjust it with default ImageView properties - then You can make 9Patch from your image and use it as a background also (in 9patch you decide by yourself how to scratch image and where to place content). You can find 9patch tool in android SDK. More info about 9patch:
http://developer.android.com/reference/android/graphics/NinePatch.html

I had this same problem. What I ended up doing was using a negative margin on the top of the ImageView like so:
android:layout_marginTop="-4dp"
You may have to play around to find the optimal number of dp for you. Hope this helps.

Android App Background Colour Not Setting

I've recently started working on an Android app. I'm not a programming noob, I have been programming in Java since 2009, but this is my first Android app. I have tried following some tutorials on how to set the background colour but it simply isn't working for me. I can't work out what I'm doing wrong.
In my layout directory I have files called: main.xml and view_fact.xml. They both use the linear layout and my LinearLayout Tag is as follows:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#color/background_grey"
>
And in my "values" directory I the contents of "strings.xml" is:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">Facts</string>
<color name="background_grey">#E8E8E8</color>
</resources>
But the background colour is not changing from the default black.
I've also tried adding: "android:theme="#android:style/Theme.Light"" in my AndroidManifest.xml file.
None of this is working, any suggestions?
Thank you.
On my view_fact.xml page it looks like this:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#color/background_grey"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Fact:"
android:padding="10dp"
android:textColor="#080808"
/>
<TextView
android:id="#+id/factData"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="10dp"
android:text=""
/>
<Button
android:id="#+id/anotherFactButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Another Fact"/>
</LinearLayout>
What's interesting is that the text in "factData" is grey, while the text: "Fact:" in the Text View above is white, and I've tried to change it's colour to red and it doesn't work. It stays white.
Any suggestions? I still haven't managed to get this working; thank you.

If you want to use #color/color_name you have to create a Color.xml file and then it will be accessible in the manner you tried to use it.

Forgive the somewhat obvious questions, but: are you calling setContentView(R.layout.main) in your Activity onCreate? Is there something else in the layout that is filling the LinearLayout and covering the background grey?

Looking at the pastie you linked in the comment I think you need to remove the <?xml version="1.0" encoding="utf-8"?> line at the start. Eclipse won't build a freshly created app with that xml root in a layout..
Although that's strange as the first two examples I've found on the Android Developer site (for example) include it
I'd be interested to see what happens if you remove that line...
In Eclipse if I use
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#E8E8E8"
>
then the background colour changes.
If I change that to
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#string/background_grey"
>
by adding <string name="background_grey">#E8E8E8</string> to /res/values/strings.xml the background changes.
This also works if I declare it as android:background="#color/background_grey" in the layout and <color name="background_grey">#E8E8E8</color> in strings.xml
and if I setup res/values/colors.xml <= I've used colors.xml (while you've used color.xml) however http://developer.android.com/guide/topics/resources/more-resources.html tells us the filename is arbitrary as you can see by the declaration working in the strings.xml file
<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="background_grey">#E8E8E8</color>
</resources>
and declare the layout as
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#color/background_grey"
>
then the background also changes...
If it doesn't behave the same for you then there's something funky going on or you're using a different layout than the simple example above and, well, there's something funky going on in that layout.

Okay, I've tried lots of different methods of trying to set the background colour and none of them are working. And I'm now having problems with text not updating. So I'm going to try remaking it. Using eclipse and ill make a new question if I'm still having issues. Thanks for the suggestions.