Develop Reference

Material Button won't cast white elevation shadow on Android 11

I have a Material Button (from Google's Material Components) which can cast black shadow normally. But when I change the shadow color, it won't appear at all. Here's the button's XML portion :
<com.google.android.material.button.MaterialButton
android:id="#+id/next"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="#dimen/margin_activity_horizontal"
android:enabled="false"
android:elevation="8dp"
android:layout_margin="16dp"
android:text="#string/setup_next"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toBottomOf="#id/nickname_entry_wrapper"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
tools:enabled="true"
android:textSize="18sp"
android:textColor="#000000"
android:backgroundTint="#FFFFFF"
android:fontFamily="#font/poppins_semibold"
android:paddingVertical="12dp"
android:outlineAmbientShadowColor="#FFFFFFFF"
android:outlineSpotShadowColor="#FFFFFFFF"
android:outlineProvider="background"
android:translationZ="8dp"
/>
As you can see, outlineAmbientShadowColor and outlineSpotShadowColor are supposed to change the shadow color that results from elevation and Z translation, right ? I tried adding both elevation and Z translation at once but nothing works, the button still has 0 shadow.
The button is a child view of a Constraint Layout that has a black background. As you can see, I even tried using different values for outlineProvider such as bounds or paddedBounds, yet..nothing.
If anyone has experience with these outline attributes, I'd love to have this solved. The problem isn't specific to Android 11 only, I am just saying that I am using Android 11 for testing, since those outline attributes are only available on Android versions later than Oreo.

As Mike M. has mentioned in the comment, those attributes don't really change the color, they just add a little 'tint'.
If you wanna use material buttons with more features, you should take a look at this library :
Github Repo: Carbon by ZieIony
It should fulfill the required objective (casting white shadows) successfully and without issues on all Android APIs.

Android support design floating action button elevation not visible for colors other than white

I'm using compile 'com.android.support:design:23.1.1' and android.support.design.widget.FloatingActionButton to create a FAB.
When the background tint color is white the elevation (shadow) is very visible.
But for other colors the elevation not visible.
Here is my code:
<android.support.design.widget.FloatingActionButton
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/create_floating_button"
app:elevation="6dp"
app:borderWidth="0dp"
android:clickable="true"
app:backgroundTint="#color/colorAccent"
app:rippleColor="#color/colorAccentLight"
android:layout_margin="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
Beside this problem, even with white color, the button doesn't seem like the ones in google material design spec.
Check this for example (the shadow's direction is down):
What am I doing wrong?

Make sure you have a specific layout-v21 file where you replace app:elevation with android:elevation. After API 21 you need to do this to maintain a good compatibility.

android.support.design.widget.FloatingActionButton implenetation of FAB reduces image size

So I have started migrating to the official support design library for an Android app of mine, replacing elements as I go. I just replaced an FAB (implemented as ImageButton) with official android.support.design.widget.FloatingActionButton. But the icon inside the button is smaller as compared to the one it was in ImageButton. What may have been a reason?
FloatingActionButton's implementation:
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/icon" />
Tried adding app:fabSize="normal but that didn't work, either.
This is how it looks after using FloatingActionButton:
And this is how it looked like while using it as a ImageButton:

Set scale type to android:scaleType="center"

Just a guess since you haven't provided any details at all. The design library's FloatingActionButton has padding calculations which will shrink the icon if it is too large, whereas your ImageButton probably just centers the icon with no scaling at all. I'm guessing that you would not observe this behavior if you were using a correctly sized 24dp icon, like the ones you get from: https://www.google.com/design/icons/.

You can use : app:maxImageSize="..dp" to change the size of your icon!

How to add shadow to the FAB provided with the android support design library?

The title is pretty self explaining.
The following code does not render shadow below the Floating Action Button. What can be done to render shadow? Is this feature really not supported even on API 21+?
<android.support.design.widget.FloatingActionButton
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:src="#drawable/ic_add"
android:clickable="true" />
Note: Adding android:elevation does not add shadow on API 21.
Screenshot taken from the example by dandar3:
https://github.com/dandar3/android-support-design

Simply setting app:borderWidth="0dp" resolve this issues for me.
Note: don't forget to add xmlns:app="http://schemas.android.com/apk/res-auto" to your root layout.
This issue should be fixed in next release of android design library.

For API 21+ you need to set app:borderWidth="0dp" and app:elevation="[number]dp". Setting elevation you are giving the size of shadow that you want:
Here is an example of code for API 21+:
<android.support.design.widget.FloatingActionButton
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/locate_user_FAB"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/location_off"
app:elevation="6dp"
app:borderWidth="0dp"
android:layout_above="#+id/take_taxi_FAB"
app:backgroundTint="#color/colorAccentGrey">
One important thing to remember for APIs below to 21 (Android 4), is for terms of compatibility FAB will put a margins around your button to draw the shadow. Then you should do something like that (I'm currently using this code and works):
<android.support.design.widget.FloatingActionButton
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/locate_user_FAB"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/location_off"
app:elevation="6dp"
app:borderWidth="0dp"
android:layout_above="#+id/take_taxi_FAB"
android:layout_alignParentRight="true"
android:layout_marginRight="#dimen/map_FAB_marginRight"
android:layout_marginBottom="#dimen/locate_user_FAB_marginBottom"
app:backgroundTint="#color/colorAccentGrey">
I prefer to put xmlns:app="http://schemas.android.com/apk/res-auto" at the beginning of the XML, but I put there just to remind you ;]

I was experiencing this same issue and I got it to work by deleting this tag from my AndroidManifest.xml.
android:hardwareAccelerated="false"
I initially added it, together with android:largeHeap="true", because I thought I needed it for a HeatMap in which a large number of points where shown, but then I realized it could work just with android:largeHeap="true".

If this still isn't working for some, there is a significant difference between:
app:elevation="6dp"
app:borderWidth="0dp"
and
app:borderWidth="0dp"
app:elevation="6dp"
Order seems to matter for some reason (The first order works, second doesn't) and this is from the support library 23.3.0

Check manifest in project or libraries in Application tag and delete them
android:hardwareAccelerated="false"
android:largeHeap="true"
But if you need these options then shadows and transformation animations will not work

In case it help, I was using
android:tint="#color/myColor"
instead of
android:backgroundTint="#color/myColor".
Replacing tint by backgroundTint brought back the shadow.

Android 5.0 - ProgressBar cannot be displayed over a Button

I think the title is pretty explicit about my problem... So here is my layout :
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<Button
android:id="#+id/button_action"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Login" />
<ProgressBar
android:id="#+id/progress_bar"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_centerInParent="true"/>
</RelativeLayout>
On android SDKs < 21, no problem, the ProgressBar is correctly displayed over the Button and centered in the Button. But on Android 5.0, the ProgressBar is displayed behind the Button.
So you can see it's correctly positionned it when you activate the option "Show layout bounds" in Developer Options settings, but you can't see anything on the screen without that option.
Would anybody know how to fix this? I guess it's a matter of elevation recently introduced, but I really don't know how to take care of it.
For the record, I'm using the recently released Theme.AppCompat style from the support.v7.
EDIT:
I also tried to apply setElevation(0) and setTranslationY(0) to the Button programmatically but it didn't change anything. So I wonder if it has to deal with the elevation.

You can add the android:translationZ attribute to the ProgressBar:
<ProgressBar
android:id="#+id/progress_bar"
android:layout_width="50dp"
android:layout_height="50dp"
android:translationZ="2dp"
android:layout_centerInParent="true"/>

Same issue here, my simple "hack" was too wrap the Button into another FrameLayout.
This way I don't care about the api version and other elevation issue ;)
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center" >
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<Button
android:id="#+id/button_action"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Login" />
</FrameLayout>
<ProgressBar
android:id="#+id/progress_bar"
android:layout_width="50dp"
android:layout_height="50dp" />
</FrameLayout>

Same question being asked here, with a better explanation of the issue:
https://stackoverflow.com/a/27216368/235910
To quote #CommonsWare:
The problem appears Android 5.0's elevation property. Apparently,
the RelativeLayout Z-axis ordering is tied into elevation. If both
widgets have the same elevation, the RelativeLayout will determine
the Z-axis order -- you can see that if you were to switch your layout
to be both Button widgets, for example. However, if one widget
(Button) has an elevation, and another widget (ImageView) does
not, the elevation will take precedence.
You can remove the Button elevation via
android:stateListAnimator="#null" or by defining your own custom
animator. Or, you can add some elevation to your ImageView to
get it to be higher on the Z axis than is the Button.

It is better to set android:translationZ more than 2dp. Your view/widget will disappear when you press the button. I explained the reason here.
<!-- Elevation when button is pressed -->
<dimen name="button_elevation_material">1dp</dimen>
<!-- Z translation to apply when button is pressed -->
<dimen name="button_pressed_z_material">2dp</dimen>
Button have these two values and defined in the framework.

If you add 'androidx.core:core' to your build.gradle, you can use this code for API < 21:
ViewCompat.setTranslationZ(viewToElevate, 5);

By default, if you want to show a view on top of a Button, it should have an elevation of at least 2dp.
This is caused by the fact that the elevation of a button is governed by their stateListAnimator. So long as it has one, setting the elevation to the button itself doesn't do anything. The stateListAnimator of Widget.MaterialComponents.Button has a default elevation of #dimen/mtrl_btn_elevation (2dp), so that's the elevation you have to take into account.
Doing android:stateListAnimator="#null" will also work, but that will get rid of any shadow effects at the button.