Develop Reference

How to professionally organise the styling of buttons? (SDK 26+, min SDK 21)

What is best practice to organise styling of buttons of a professional android application? Assume a larger contemporary application (SDK 26+, min SDK 21).
This question is answerable, as both the sources of Material Design and the setup of Android Studio give enough clues and examples of the patterns of the intended professional usage. Surely the user is not limited to this patterns, but following them, makes the application play well together with the sources of Material Design and provides best maintainability.
I find several ingredients related to the styling of buttons.
#style/Widget.AppCompat.Button
#style/Widget.AppCompat.Button.Colored
#style/TextAppearance.AppCompat.Button
#style/TextAppearance.AppCompat.Widget.Button
#color/foreground_material_dark
?colorAccent
?textColorPrimary
?android:colorForeground
?textAppearanceButton
There may be more.
How are all the ingredients related?
How are they intended to be used together in professional theming?
You can look up the sources. However, even knowing all details does not give the full picture of the intended usage. This question is asking to draw the picture.

(Min SDK 21)
General Approach
Granularity
I think it an enough fine-grained approach to separate the text appearance from the backgrounds. This gives the option to combine different backgrounds with different text appearances. It also matches the two style settings provided by Button and the organisation of Material Design. Hence it addresses the question, how it is intended to be used.
The price is, that each Button needs both settings:
Button text: android:textAppearance
Button background: style
To even lower this price styles_material.xml in fact takes an advanced approach. Each button style already includes a default text appearance. So in the normal case I only have to apply the button style.
<Button
style="?defaultButtonStyle"
I follow this pattern for my own button styling, as the question is for the intended usage. If I want to modify the default, I add an alternative text appearance by setting it to android:textAppearance.
<Button
style="?defaultButtonStyle"
android:textAppearance="?smallButtonTextAppearance"
For very special buttons I still can adjust the styling on the level of the layout file. This is the lowest level of granularity.
Hint: Be aware that android:textAppearance has a very low
precedence. If you set a text attribute somewhere in the theme (or style),
you will overwrite the same attribute in all of android:textAppearance.
It works with a similar force like the "!important" annotation in CSS,
which can be a pretty pitfall.
Flexible theming
Without
If I don't plan to use different themes, I can set the styles directly into the layouts.
<Button
style="#style/My.DefaultButtonStyle"
android:textAppearance="#style/My.SmallButtonTextAppearance"
...
With
If a want to be able to exchange themes, I map all types of styles to attributes first. Then I set the styles indirectly by using the attributes. This gives me the option to connect other styles for other themes, without the need to duplicate layouts.
<Button
style="?defaultButtonStyle"
android:textAppearance="?smallButtonTextAppearance"
...
I personally prefer not to use or mix given attributes, but to fully define my own set of attributes addressing my design. So the levels of the onion stay cleanly separated.
<?xml version="1.0" encoding="utf-8" ?>
<resources>
<!-- button text appearance -->
<attr name="defaultButtonTextAppearance" format="reference" />
<attr name="smallButtonTextAppearance" format="reference" />
<!-- button backgrounds -->
<attr name="defaultButtonStyle" format="reference" />
<attr name="alarmButtonStyle" format="reference" />
In the themes the attributes are mapped to theme specific styles.
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="OtherTheme" parent="Theme.AppCompat">
<!-- button text appearance -->
<item name="defaultButtonTextAppearance">#style/OtherTheme.DefaultButtonTextAppearance</item>
...
<!-- button backgrounds -->
<item name="defaultButtonStyle">#style/OtherTheme.DefaultButtonStyle</item>
...
Button Text
If I track down the styles to the sources I come to a file data/res/values/styles_material.xml, which defines the root of all button text appearances. TextAppearance.Material.Button inherits from TextAppearance.Material, but the four relevant attributes for buttons are overwritten.
<style name="TextAppearance.Material">
<item name="textColor">?attr/textColorPrimary</item>
<item name="textColorHint">?attr/textColorHint</item>
<item name="textColorHighlight">?attr/textColorHighlight</item>
<item name="textColorLink">?attr/textColorLink</item>
<item name="textSize">#dimen/text_size_body_1_material</item>
<item name="fontFamily">#string/font_family_body_1_material</item>
<item name="lineSpacingMultiplier">#dimen/text_line_spacing_multiplier_material</item>
</style>
<style name="TextAppearance.Material.Button">
<item name="textSize">#dimen/text_size_button_material</item>
<item name="fontFamily">#string/font_family_button_material</item>
<item name="textAllCaps">true</item>
<item name="textColor">?attr/textColorPrimary</item>
</style>
It can be overwritten by my own inherited styles. It also shows, that it would be easy to write my own text appearance style without using inheritance at all.
Color
Understanding Androids text color management system is them most confusing part, because the system is quite powerful. Here comes some enlightenment.
In the above TextAppearance.Material.Button I find text color is specified by the attribute ?textColorPrimary. This attribute again is based on the attribute ?android:colorForeground.
The attribute ?android:colorForeground is the central switch to set the text colors. Be default all text colors are calculated based on this setting, also those of the buttons. For example different grades of greyed-out or opaque variants are calculated for disabled buttons, for body text, etc.
Instead of touching dozens of different places it is a good idea to set the common default text color here and rely on the default Android color calculating system as far as useful. Tweak it in details.
<item name="android:colorForeground">#color/orange_700</item>
This setting defaults to #color/foreground_material_dark.
Hint 1: If you edit the setting by use of
the Android Studio Theme Editor, it will possibly change the
value of#color/foreground_material_dark. To me it does not
feel like a good idea to change a value of material dark because
it is not my realm. Better use a reference like shown before.
Hint 2: The Theme Editor is an appropriate tool to discover
the relations of the color attributes system. This relations reveal,
when you experimentally try to edit the different attributes with the editor.
If I want a button text color that varies from the overall text color, I set it on the level of the text appearance style.
Hint 3: Using ?android:colorForeground does not work out of the
box below API 26. For a workaround see here.
Text size
The text size is the factor of the text appearance, that I typically want to directly adjust to my own design within my customised text appearance styles.
<style name="My.SmallButtonTextAppearance" parent="My.DefaultButtonTextAppearance">
<item name="android:textSize">16sp</item>
</style>
TextAppearance.Material.Button takes the text size default from the resource #dimen/text_size_button_material. There is no system with a central text size setting comparable to the text color setting system.
All caps
The root style TextAppearance.Material.Button set's all caps to true. There is not even a resource, the value is taken from. It's just hard coded.
<item name="textAllCaps">true</item>
There is a high chance, I want to set it to false in my customised button styles.
<item name="android:textAllCaps">false</item>
Font family
As with the text colors the font family typically is a system with a common central nature. How is it managed for the buttons? The root style TextAppearance.Material.Button makes use a the string resource #string/font_family_button_material.
<item name="fontFamily">#string/font_family_button_material</item>
In the file data/res/values/donttranslate_material.xml this is set to sans-serif-medium, while in the file data/res/values-watch/donttranslate_material.xml is is set to sans-serif-condensed.
<string name="font_family_button_material">sans-serif-medium</string>
<string name="font_family_button_material">sans-serif-condensed</string>
This sans-serif settings are mapped to my chosen font family within the fonts setup. Typically sans-serif is fine for button text. For further customisation of the fonts I point to this question.
Button Style
Apart from using a color for the background, a xml resource file can be applied to specify the background with fancy corners, color gradients or other graphical effects, also supporting different backgrounds for different states of the button.
This part is strongly influenced by my design. I will typically use my own background.
On the other hand there is a rich system of predefined button backgrounds resource files in material design. I would like to give a short overview here, but that's beyond my skills and seems so large to be worth a topic of it's own.
The style for the background should not contain settings for width, height or margins, as this belongs into the surrounding layout. On the other hand the padding belongs into the background style.
Button styles of Material Design
In the file data/res/values/styles_material.xml I find nine button styles I may inherit from. If I write my very own, a should not forget to set a default text appearance.
The root element is Widget.Material.Button. It set's the default text appearance to ?textAppearanceButton. Hence, setting this attribute is an option to directly use the material design button styles without inheritance and yet have your customised default text appearance.
<!-- Bordered ink button -->
<style name="Widget.Material.Button">
<item name="background">#drawable/btn_default_material</item>
<item name="textAppearance">?attr/textAppearanceButton</item>
<item name="minHeight">48dip</item>
<item name="minWidth">88dip</item>
<item name="stateListAnimator">#anim/button_state_list_anim_material</item>
<item name="focusable">true</item>
<item name="clickable">true</item>
<item name="gravity">center_vertical|center_horizontal</item>
</style>
The attribute ?colorAccent is used, to set the color of Widget.AppCompat.Button.Colored. See the Android Studio Theme Editor. See #drawable/btn_colored_material.
Note that the default text appearance of Widget.AppCompat.Button.Colored varies and is not set by a customisable attribute.
<!-- Colored bordered ink button -->
<style name="Widget.Material.Button.Colored">
<item name="background">#drawable/btn_colored_material</item>
<item name="textAppearance">#style/TextAppearance.Material.Widget.Button.Colored</item>
</style>
<!-- Small bordered ink button -->
<style name="Widget.Material.Button.Small">
<item name="minHeight">48dip</item>
<item name="minWidth">48dip</item>
</style>
<!-- Borderless ink button -->
<style name="Widget.Material.Button.Borderless">
<item name="background">#drawable/btn_borderless_material</item>
<item name="stateListAnimator">#null</item>
</style>
Note that the default text appearance of Widget.Material.Button.Borderless.Colored varies and is not set by a customisable attribute.
<!-- Colored borderless ink button -->
<style name="Widget.Material.Button.Borderless.Colored">
<item name="textAppearance">#style/TextAppearance.Material.Widget.Button.Borderless.Colored</item>
</style>
Note that Widget.Material.Button.ButtonBar.AlertDialog inherits from Widget.Material.Button.Borderless.Colored. Same limitations of the default text appearance apply.
<!-- Alert dialog button bar button -->
<style name="Widget.Material.Button.ButtonBar.AlertDialog" parent="Widget.Material.Button.Borderless.Colored">
<item name="minWidth">64dp</item>
<item name="minHeight">#dimen/alert_dialog_button_bar_height</item>
</style>
<!-- Small borderless ink button -->
<style name="Widget.Material.Button.Borderless.Small">
<item name="minHeight">48dip</item>
<item name="minWidth">48dip</item>
</style>
<style name="Widget.Material.Button.Inset">
<item name="background">#drawable/button_inset</item>
</style>
<style name="Widget.Material.Button.Toggle">
<item name="background">#drawable/btn_toggle_material</item>
<item name="textOn">#string/capital_on</item>
<item name="textOff">#string/capital_off</item>
</style>
Personally I would either use one of this predefined button styles or inherit my own from Widget.Material.Button. This keeps the hierarchy of inheritance low and the code easily readable. It saves me at most three lines of code if I inherit from another style, while the code becomes less maintainable.
There are exceptions to this rule of thumb. For example #drawable/btn_borderless_material is private. So I either have to inherit from Widget.Material.Button.Colored or create a copy of the file.
Appendix
Related questions
Attributes
Defining custom attrs
Android Use custom themes to modify style attributes
Android "?colorPrimary" vs "?attr/colorPrimary"?
Inheritance issue, when using property androidTextapperance vs. property style
Colors
Setting a color based on theme
Attribute android:colorForeground not working in API 23
android themes - defining colours in custom themes
Fonts
How to set default font family for entire Android app
How to change fontFamily of TextView in Android
What is the difference between fontFamily and typeFace in android?

it's up to you and depends on your application.. also you can set a background using an xml file
eg:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" >
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<corners android:radius="20dp" />
<solid android:color="#8c0000" />
</shape>
</item>
<item >
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<corners android:radius="20dp" />
<solid android:color="#c62f2c" />
</shape>
</item>
</selector>

Error inflating ImageView / ImageButton with ColorStateList tint value

Using an ImageView / ImageButton (AppCompatImageView / AppCompatImageButton) in conjunction with a style attribute of android:tint which makes use of a ColorStateList resource works fine on >= API 21, but throws an InflateException on API < 21.
Firstly, I don't even know whether the AppCompatImageView / (Button) tinting supports ColourStateList xml resources as an android:tint value, I can't seem to find a definitive answer to this. Suggestions I can find on S/O suggest implementing a TintableImageView etc, but these answers are quite dated, and it seems from the source of the appcompat implementations this should be a feature.
To clarify this is definitely the issue. Removing the android:tint attribute or setting it to a single colour resource works.
Also to clarify, I'm aware this is achievable programmatically. I'm trying to get it backwards compatible in xml.
Minimal example
activity_foo.xml
<android.support.v7.widget.AppCompatImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_caret_up"
style="#style/IconButton.Primary"
/>
styles.xml
<style name="IconButton.Primary">
<item name="android:tint">#color/link_button_color</item>
</style>
link_button_color.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:color="#color/btnLinkPressedTextColor"
android:state_selected="true" />
<item android:color="#color/btnLinkPressedTextColor"
android:state_pressed="true" />
<item android:color="#color/btnLinkTextColor" />
</selector>

In my case i replaced android:tint with app:tint and added to root element xmlns:app="http://schemas.android.com/apk/res-auto". It fixed crashing issue on API level < 21.
And color state selector /res/color/color_selector.xml looks like:
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:color="#151515"/>
<item android:state_focused="true" android:color="#151515"/>
<item android:color="#424242"/>
</selector>

It looks like AppCompat drawable tinting only works for action bar and "some widgets" on < API 21, but works for all drawables on API 21+.
When you set these attributes, AppCompat automatically propagates their values to the framework attributes on API 21+. This automatically colors the status bar and Overview (Recents) task entry.
On older platforms, AppCompat emulates the color theming where possible. At the moment this is limited to coloring the action bar and some widgets.
Source: https://android-developers.googleblog.com/2014/10/appcompat-v21-material-design-for-pre.html
The answer here also has more detail: https://stackoverflow.com/a/29155611/608312

item name="android:tint" is wrong.
fix the 'android:tint' to 'tint'
<style name="IconButton.Primary">
<item name="tint">#color/link_button_color</item>
</style>

Cannot change android Switch style when using Holo Everywhere

I am having trouble changing the style of a Switch view in my project and can't figure out what I am doing wrong or missing... My project uses holo everywhere.
I can't change the text, the thumb or the track. I've tried applying android:thumb and android:track drawables directly from the xml but nothing changes. Not even the android:textOff and android:textOn have any effect.
I found a great post on how to customise the android Switch view style and looked through all the code but couldn't find anything I was doing wrong:
http://custom-android-dn.blogspot.co.uk/2013/01/how-to-use-and-custom-switch-in-android.html
Really not sure what else to try.
Here is the xml code:
<Switch
android:id="#+id/home_availability_switch"
style="#style/MySwitch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:enabled="true"
android:focusable="true"
android:textOff="Free"
android:textOn="Busy" />
Here is the style:
<style name="MySwitch" parent="#style/Holo.Switch.Light">
<item name="android:thumb">#drawable/selector_availability_switch_thumb</item>
<item name="android:track">#drawable/selector_availability_switch_background</item>
</style>
Here is the thumb selector
(these are default system drawables. i have tried with different drawables):
<item android:drawable="#drawable/switch_thumb_pressed_holo_light" android:state_pressed="true"/>
<item android:drawable="#drawable/switch_thumb_activated_holo_light" android:state_checked="true"/>
<item android:drawable="#drawable/switch_thumb_disabled_holo_light" android:state_enabled="false"/>
<item android:drawable="#drawable/switch_thumb_holo_dark"/>
Here is the track selector
(these are default system drawables. i have tried with different drawables):
<item android:drawable="#drawable/switch_bg_disabled_holo_dark" android:state_enabled="false"/>
<item android:drawable="#drawable/switch_bg_focused_holo_dark" android:state_focused="true"/>
<item android:drawable="#drawable/switch_bg_holo_dark"/>
I also found this post How can I style an Android Switch? and follow the instructions but had no luck.
Any one else had a similar experience when using Holo Everywhere?

You need to define the switch like this. Need the whole package name in there for it to work.
<org.holoeverywhere.widget.Switch
android:id="#+id/lockSwitch"
style="?switchStyleOld"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TestSwitch" />
Hope this helps.

How can I style an Android Switch?

The switch widget introduced in API 14 is styled by default with holo theme.
I want to style it slightly different, changing its colors and shape a bit for branding reasons. How does one go about this? I know it must be possible, as ive seen the difference between default ICS and Samsung's touchwiz theme
I assume I'll need some state drawables, and I've seen a few styles in http://developer.android.com/reference/android/R.styleable.html with Switch_thumb and Switch_track that look like what I might be after. I just don't know how to go about using them.
I'm using ActionbarSherlock if that makes a difference. Only devices running API v14 or above will be able to use a switch at all, of course.

You can define the drawables that are used for the background, and the switcher part like this:
<Switch
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:thumb="#drawable/switch_thumb"
android:track="#drawable/switch_bg" />
Now you need to create a selector that defines the different states for the switcher drawable.
Here the copies from the Android sources:
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="false" android:drawable="#drawable/switch_thumb_disabled_holo_light" />
<item android:state_pressed="true" android:drawable="#drawable/switch_thumb_pressed_holo_light" />
<item android:state_checked="true" android:drawable="#drawable/switch_thumb_activated_holo_light" />
<item android:drawable="#drawable/switch_thumb_holo_light" />
</selector>
This defines the thumb drawable, the image that is moved over the background. There are four ninepatch images used for the slider:
The deactivated version (xhdpi version that Android is using)
The pressed slider:
The activated slider (on state):
The default version (off state):
There are also three different states for the background that are defined in the following selector:
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="false" android:drawable="#drawable/switch_bg_disabled_holo_dark" />
<item android:state_focused="true" android:drawable="#drawable/switch_bg_focused_holo_dark" />
<item android:drawable="#drawable/switch_bg_holo_dark" />
</selector>
The deactivated version:
The focused version:
And the default version:
To have a styled switch just create this two selectors, set them to your Switch View and then change the seven images to your desired style.

It's an awesome detailed reply by Janusz. But just for the sake of people who are coming to this page for answers, the easier way is at http://android-holo-colors.com/ (dead link) linked from Android Asset Studio
A good description of all the tools are at AndroidOnRocks.com (site offline now)
However, I highly recommend everybody to read the reply from Janusz as it will make understanding clearer. Use the tool to do stuffs real quick

You can customize material styles by setting different color properties.
For example custom application theme
<style name="CustomAppTheme" parent="Theme.AppCompat">
<item name="android:textColorPrimaryDisableOnly">#00838f</item>
<item name="colorAccent">#e91e63</item>
</style>
Custom switch theme
<style name="MySwitch" parent="#style/Widget.AppCompat.CompoundButton.Switch">
<item name="android:textColorPrimaryDisableOnly">#b71c1c</item>
<item name="android:colorControlActivated">#1b5e20</item>
<item name="android:colorForeground">#f57f17</item>
<item name="android:textAppearance">#style/TextAppearance.AppCompat</item>
</style>
You can customize switch track and switch thumb like below image by defining xml drawables. For more information http://www.zoftino.com/android-switch-button-and-custom-switch-examples

Alternative and much easier way is to use shapes instead of 9-patches.
It is already explained here:
https://stackoverflow.com/a/24725831/512011

Default Eclipse Theme for Android Development Spinners?

The color of my Spinner widgets change from phone to phone based on there settings,I would like to keep them the same between all phones and I would like to have it be the default eclipse uses in its emulators the color is silverish. Can you please let me know how to apply this specific theme to my Spinner in xml. Thanks in advance.

download the images used in for the spinner from the android source code: spinner_press.9.png, spinner_select.9.png, spinner_normal.9.png then create selector using those.
this is the default selector:
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true"
android:drawable="#drawable/spinner_press" />
<item android:state_pressed="false" android:state_focused="true"
android:drawable="#drawable/spinner_select" />
<item android:drawable="#drawable/spinner_normal" />
</selector>

You don't need to create a theme. Just apply a background of your choice to the spinner, as with any other View.
If you want to have different backgrounds you can use a (See here for more info)
For an example of an implementation, nothing better than the android source: https://android.googlesource.com/platform/frameworks/base/+/froyo-release/core/res/res/drawable/spinner_background.xml
You can get the actual 9-patch files from there also (and choose which version you would like to use).