The Curious Case of Android Button - Yelp Engineering

Slides for the talk "The Curious Case of Android Button" by Nicola Corti, Android Engineer @ Yelp (Hamburg).

We interact with buttons every day to get coffee, order pizza, or start a new Gradle build. They may look simple and straightforward, but they have a fundamental role in our environment: create a sense of power.

We all love to feel empowered and we all hate being frustrated by bad design. Your users know this as well, they want to feel immediately rewarded when they interact with your UI, and they will quickly drop your app if they get annoyed.

At Yelp, we get tens of millions button clicks a day. At that kind of scale, every pixel matters. We tune every single aspect of our buttons to make them simple and powerful, but adjusting every single shadow cast, click animation, or color layer can be tricky. In this talk, we will provide a deep dive into the Android framework and the Support Library to understand how buttons are rendered.

1. The Curious Case of Android Button Nicola Corti @cortinico nco@yelp.com
3. Yelp Mission Connecting people with great local businesses.
4. About me Nicola Corti Android @ BizCore @cortinico Community Lover !✈
5. CC-by hisgett
9. Consistency First
10. Quick Button’s History
13. Skeuomorphic UI • Android 2.3 - iOS 6 • Easy of use
14. Flat UI • Windows Phone 7 (2010) • iOS 7+ (2013) • Streamlined & lighter • Responsive UI
15. Almost Flat (aka Flat 2.0) • Google Material Design (2014) • Shadows and
 Subtle Gradients
16. How to craft your buttons?
18. Shape
19. Rectangular Shadows Corners More about rounded corners: http://bit.ly/roundedcorner
20. Credits: Material Design - Elevation & Shadows
22. Key + Ambient = Result
24. Brand Platform CC kevint3141
25. Time to deep dive!
26. What’s actually an Android Button?
27. What’s actually an Android Button? java.lang.Object ↳ android.view.View ↳ android.widget.TextView ↳ android.widget.Button ↳ android.support.v7.widget.AppCompatButton
28. What’s actually an Android Button? java.lang.Object ↳ android.view.View ↳ android.widget.TextView ↳ android.widget.Button ↳ android.support.v7.widget.AppCompatButton
29. What’s actually an Android Button? java.lang.Object ↳ android.view.View ↳ android.widget.TextView ↳ android.widget.Button ↳ android.support.v7.widget.AppCompatButton
30. What’s actually an Android Button? java.lang.Object ↳ android.view.View ↳ android.widget.TextView ↳ android.widget.Button ↳ android.support.v7.widget.AppCompatButton
31. What’s actually an Android Button? java.lang.Object ↳ android.view.View ↳ android.widget.TextView ↳ android.widget.Button ↳ android.support.v7.widget.AppCompatButton
32. What’s actually an Android Button? java.lang.Object (554) ↳ android.view.View (26488) ↳ android.widget.TextView (11969) ↳ android.widget.Button (182) ↳ android.support.v7.widget.AppCompatButton (187)
33. Just a Button
34. Just a Button <Button />
35. Just a Button <Button android:layout_width="wrap_content" android:layout_height="wrap_content" />
36. Just a Button <android.support.v7.widget.AppCompatButton android:layout_width="wrap_content" android:layout_height="wrap_content" />
37. Just a Button /** * * <p>This will automatically be used when you use {@link Button} in your layouts */ public class AppCompatButton extends Button implements TintableBackgroundView, AutoSizeableTextView {
38. Just a Button /** * * <p>This will automatically be used when you use {@link Button} in your layouts */ public class AppCompatButton extends Button implements TintableBackgroundView, AutoSizeableTextView {
39. Just a Button /** * … * * <p>This will automatically be used when you use {@link Button} in your layouts * … */ public class AppCompatButton extends Button implements TintableBackgroundView, AutoSizeableTextView {
40. 4 defaults styles for a Button
41. 4 defaults styles for a Button <style name=“Widget.AppCompat.Button"/> <style name="Widget.AppCompat.Button.Colored"/> <style name="Widget.AppCompat.Button.Borderless"/> <style name="Widget.AppCompat.Button.Borderless.Colored"/>
42. 4 defaults styles for a Button <style name=“Widget.AppCompat.Button"/> <style name="Widget.AppCompat.Button.Colored"/> <style name="Widget.AppCompat.Button.Borderless"/> <style name="Widget.AppCompat.Button.Borderless.Colored"/> API 21+
43. 4 defaults styles for a Button <style name=“Widget.AppCompat.Button” parent="Base.Widget.AppCompat.Button"/> <style name="Widget.AppCompat.Button.Borderless"/> <style name="Widget.AppCompat.Button.Borderless.Colored"/> <style name="Widget.AppCompat.Button.Colored"/> <style name="Base.Widget.AppCompat.Button" parent="android:Widget.Material.Button"/> API 21+
44. data/res/values/styles_material.xml
45. data/res/values/styles_material.xml <!-- Bordered ink button --> <style name="Widget.Material.Button"> </style>
46. data/res/values/styles_material.xml <!-- 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>
47. data/res/values/styles_material.xml <!-- 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>
48. data/res/values/styles_material.xml <!-- 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>
49. data/res/values/styles_material.xml <!-- 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>
50. data/res/drawable/btn_default_material.xml
51. data/res/drawable/btn_default_material.xml <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <item android:drawable="@drawable/btn_default_mtrl_shape" /> </ripple>
52. data/res/drawable/btn_default_material.xml <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <item android:drawable="@drawable/btn_default_mtrl_shape" /> </ripple>
53. data/res/drawable/btn_default_material.xml <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <item android:drawable="@drawable/btn_default_mtrl_shape" /> </ripple>
54. <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <inset android:insetLeft="4dp" android:insetTop="6dp" android:insetRight="4dp" android:insetBottom="6dp"> ... </inset> </ripple>
55. <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <inset android:insetLeft="4dp" android:insetTop="6dp" android:insetRight="4dp" android:insetBottom="6dp"> <shape android:shape="rectangle" android:tint="?attr/colorButtonNormal"> ... </shape> </inset> </ripple>
56. <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <inset android:insetLeft="4dp" android:insetTop="6dp" android:insetRight="4dp" android:insetBottom="6dp"> <shape android:shape="rectangle" android:tint="?attr/colorButtonNormal"> ... </shape> </inset> </ripple>
57. <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <inset android:insetLeft="4dp" android:insetTop="6dp" android:insetRight="4dp" android:insetBottom="6dp"> <shape android:shape="rectangle" android:tint="?attr/colorButtonNormal"> ... </shape> </inset> </ripple>
58. <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <inset android:insetLeft="4dp" android:insetTop="6dp" android:insetRight="4dp" android:insetBottom="6dp"> <shape android:shape="rectangle" android:tint="?attr/colorButtonNormal"> <corners android:radius="2dp" /> ... </shape> </inset> </ripple>
59. <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <inset android:insetLeft="4dp" android:insetTop="6dp" android:insetRight="4dp" android:insetBottom="6dp"> <shape android:shape="rectangle" android:tint="?attr/colorButtonNormal"> <corners android:radius="2dp" /> <solid android:color="@color/white" /> ... </shape> </inset> </ripple>
60. <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <inset android:insetLeft="4dp" android:insetTop="6dp" android:insetRight="4dp" android:insetBottom="6dp"> <shape android:shape="rectangle" android:tint="?attr/colorButtonNormal"> <corners android:radius="2dp" /> <solid android:color="@color/white" /> <padding android:left="8dp" android:top="4dp" android:right="8dp" android:bottom="4dp" /> </shape> </inset> </ripple>
61. <ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?attr/colorControlHighlight"> <inset android:insetLeft="@dimen/button_inset_horizontal_material" android:insetTop="@dimen/button_inset_vertical_material" android:insetRight="@dimen/button_inset_horizontal_material" android:insetBottom="@dimen/button_inset_vertical_material"> <shape android:shape="rectangle" android:tint="?attr/colorButtonNormal"> <corners android:radius="@dimen/control_corner_material" /> <solid android:color="@color/white" /> <padding android:left="@dimen/button_padding_horizontal_material" android:top="@dimen/button_padding_vertical_material" android:right="@dimen/button_padding_horizontal_material" android:bottom=“@dimen/button_padding_vertical_material" /> </shape> </inset> </ripple>
62. Typography
63. Typography • Use a verb • On Android, buttons are ALL CAPS • Principle of Least astonishment
64. Typography
65. Typography <Button android:layout_width="wrap_content" android:layout_height="wrap_content"/>
66. Typography <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Log In"/>
67. Typography <Button style="@style/Base.Widget.AppCompat.Button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Log In"/>
68. res/values/styles_material.xml
69. res/values/styles_material.xml <!-- 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> <style name="TextAppearance.Material.Button"> <item name="textSize">@dimen/text_size_button_material</item> <item name="fontFamily">@string/font_family_button_material</item>
70. res/values/styles_material.xml <!-- 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> <style name="TextAppearance.Material.Button"> <item name="textSize">@dimen/text_size_button_material</item> <item name="fontFamily">@string/font_family_button_material</item>
71. <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> <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>
72. <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> <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>
73. Hierarchy
74. Hierarchy • First, define your color palette • Use contrast to define hierarchy • Primary: high • Negative: medium • Secondary: low
77. Hierarchy
78. Hierarchy <style name=“Widget.AppCompat.Button"/> <style name="Widget.AppCompat.Button.Colored"/> <style name="Widget.AppCompat.Button.Borderless"/> <style name="Widget.AppCompat.Button.Borderless.Colored"/>
79. Hierarchy <style name=“Widget.AppCompat.Button"/> <style name="Widget.AppCompat.Button.Colored"/> <style name="Widget.AppCompat.Button.Borderless"/> <style name="Widget.AppCompat.Button.Borderless.Colored"/> API 23+
80. Hierarchy <style name=“Widget.AppCompat.Button"/> <style name=“Widget.AppCompat.Button.Colored” parent=“Base.Widget.AppCompat.Button.Colored”/> <style name="Widget.AppCompat.Button.Borderless"/> <style name=“Widget.AppCompat.Button.Borderless.Colored"/> <style name=“Base.Widget.AppCompat.Button.Colored" parent=“android:Widget.Material.Button.Colored”/> API 23+
81. data/res/values/styles_material.xml
82. data/res/values/styles_material.xml <!-- Bordered ink button --> <style name="Widget.Material.Button"> ... </style>
83. data/res/values/styles_material.xml <!-- Bordered ink button --> <style name="Widget.Material.Button"> </style> <!-- Colored bordered ink button --> <style name="Widget.Material.Button.Colored"> </style>
84. data/res/values/styles_material.xml <!-- Bordered ink button --> <style name="Widget.Material.Button"> </style> <!-- 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>
85. data/res/values/styles_material.xml <!-- Bordered ink button --> <style name="Widget.Material.Button"> </style> <!-- 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>
86. data/res/values/styles_material.xml <!-- Bordered ink button --> <style name="Widget.Material.Button"> </style> <!-- 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>
87. data/res/values/styles_material.xml <!-- Bordered ink button --> <style name="Widget.Material.Button"> </style> <!-- 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>
88. data/res/drawable/btn_colored_material.xml
89. <inset xmlns:android="http://schemas.android.com/apk/res/android" android:insetLeft="@dimen/button_inset_horizontal_material" android:insetTop="@dimen/button_inset_vertical_material" android:insetRight="@dimen/button_inset_horizontal_material" android:insetBottom="@dimen/button_inset_vertical_material"> <ripple android:color="?attr/colorControlHighlight"> <item> <shape android:shape="rectangle" android:tint="@color/btn_colored_background_material"> <corners android:radius="@dimen/control_corner_material" /> <solid android:color="@color/white" /> <padding android:left="@dimen/button_padding_horizontal_material" android:top="@dimen/button_padding_vertical_material" android:right="@dimen/button_padding_horizontal_material" android:bottom="@dimen/button_padding_vertical_material" /> </shape> </item> </ripple> </inset> data/res/drawable/btn_colored_material.xml
90. <inset xmlns:android="http://schemas.android.com/apk/res/android" android:insetLeft="@dimen/button_inset_horizontal_material" android:insetTop="@dimen/button_inset_vertical_material" android:insetRight="@dimen/button_inset_horizontal_material" android:insetBottom="@dimen/button_inset_vertical_material"> <ripple android:color="?attr/colorControlHighlight"> <item> <shape android:shape="rectangle" android:tint="@color/btn_colored_background_material"> <corners android:radius="@dimen/control_corner_material" /> <solid android:color="@color/white" /> <padding android:left="@dimen/button_padding_horizontal_material" android:top="@dimen/button_padding_vertical_material" android:right="@dimen/button_padding_horizontal_material" android:bottom="@dimen/button_padding_vertical_material" /> </shape> </item> </ripple> </inset> data/res/drawable/btn_colored_material.xml
91. data/res/color/btn_colored_background_material.xml
92. data/res/color/btn_colored_background_material.xml <selector xmlns:android="http://schemas.android.com/apk/res/ android"> </selector>
93. data/res/color/btn_colored_background_material.xml <selector xmlns:android="http://schemas.android.com/apk/res/ android"> <item /> <item /> </selector>
94. data/res/color/btn_colored_background_material.xml <selector xmlns:android="http://schemas.android.com/apk/res/ android"> <item android:state_enabled="false" /> <item /> </selector>
95. data/res/color/btn_colored_background_material.xml <selector xmlns:android="http://schemas.android.com/apk/res/ android"> <item android:state_enabled="false" android:color="?attr/colorButtonNormal" /> <item /> </selector>
96. data/res/color/btn_colored_background_material.xml <selector xmlns:android="http://schemas.android.com/apk/res/ android"> <item android:state_enabled="false" android:alpha="?attr/disabledAlpha" android:color="?attr/colorButtonNormal" /> <item /> </selector>
97. data/res/color/btn_colored_background_material.xml <selector xmlns:android="http://schemas.android.com/apk/res/ android"> <item android:state_enabled="false" android:alpha="?attr/disabledAlpha" android:color="?attr/colorButtonNormal" /> <item android:color="?attr/colorAccent" /> </selector>
98. data/res/color/btn_colored_background_material.xml <selector xmlns:android="http://schemas.android.com/apk/res/ android"> <item android:state_enabled="false" android:alpha="?attr/disabledAlpha" android:color="?attr/colorButtonNormal" /> <item android:color="?attr/colorAccent" /> </selector>
99. Secondary color? • Use a ThemeOverlay (XML only) • Use backgroundTint
100. Secondary Color
101. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content"/>
102. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content"/>
103. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:backgroundTint=“@color/red"/>
104. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:backgroundTint=“@color/red"/>
105. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:backgroundTint=“@color/red"/>
106. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:backgroundTint=“@color/red"/>
107. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:backgroundTint=“@color/red"/> <style name="MyRedButton" />
108. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:backgroundTint=“@color/red"/> <style name="MyRedButton" parent=“ThemeOverlay.AppCompat.Light"/>
109. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:backgroundTint=“@color/red"/> <style name="MyRedButton" parent="ThemeOverlay.AppCompat.Light"> <item name=“android:colorAccent">@color/red</item> </style>
110. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:backgroundTint=“@color/red"/> <style name="MyRedButton" parent="ThemeOverlay.AppCompat.Light"> <item name=“android:colorAccent">@color/red</item> </style>
111. All works fine but…? .isEnabled = false with ThemeOverlay with backgroundTint with ThemeOverlay with backgroundTint
112. Secondary Color <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:theme=“@style/MyRedButton"/> <android.support.v7.widget.AppCompatButton style="@style/Base.Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:backgroundTint=“@color/red"/>
113. data/res/color/btn_colored_background_material.xml <selector xmlns:android="http://schemas.android.com/apk/res/ android"> <item android:state_enabled="false" android:alpha="?attr/disabledAlpha" android:color="?attr/colorButtonNormal" /> <item android:color="?attr/colorAccent" /> </selector>
114. data/res/color/btn_colored_background_material.xml <selector xmlns:android="http://schemas.android.com/apk/res/ android"> <item android:state_enabled="false" android:alpha="?attr/disabledAlpha" android:color="?attr/colorButtonNormal" /> <item android:color="@color/red" /> </selector>
115. All works fine but…? • You need a ColorStateList
 for the backgroundTint • Delegate creations of drawables/CSL
 to a UtilClass
116. Feedback
117. Feedback • Buttons are alive! • They have states (ColorStateList/StateListDrawable) • Use Ripples (they handle states) • Animate Shadows (StateListAnimator)
121. Credits: Vadim Gomov - Dribbble Z-Value = Elevation + TranslationZ
122. Shadow
123. Shadow <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:elevation="2dp"/>
124. Shadow <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:elevation="2dp"/>
125. Shadow <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:elevation="8dp"/>
126. Shadow <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:stateListAnimator="@null" android:elevation="8dp"/> Why?
127. res/values/styles_material.xml
128. res/values/styles_material.xml <!-- 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>
129. res/values/styles_material.xml <!-- 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>
130. data/res/anim/button_state_list_anim_material.xml
131. <selector xmlns:android="http://schemas.android.com/apk/res/android"> </selector> data/res/anim/button_state_list_anim_material.xml
132. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled=“true” /> <!-- rest state --> <item android:state_enabled=“true” /> <item /> </selector> data/res/anim/button_state_list_anim_material.xml
133. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled="true"> <set> <objectAnimator android:propertyName="translationZ" android:duration="@integer/button_pressed_animation_duration" android:valueTo="@dimen/button_pressed_z_material" android:valueType="floatType"/> <objectAnimator android:propertyName="elevation" android:duration="0" android:valueTo="@dimen/button_elevation_material" android:valueType="floatType"/> </set> </item> <!-- rest state --> <item android:state_enabled=“true” /> <item /> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp
134. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled="true"> <set> <objectAnimator android:propertyName="translationZ" android:duration="@integer/button_pressed_animation_duration" android:valueTo="@dimen/button_pressed_z_material" android:valueType="floatType"/> <objectAnimator android:propertyName="elevation" android:duration="0" android:valueTo="@dimen/button_elevation_material" android:valueType="floatType"/> </set> </item> <!-- rest state --> <item android:state_enabled=“true” /> <item /> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp
135. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled="true"> <set> <objectAnimator android:propertyName="translationZ" android:duration="@integer/button_pressed_animation_duration" android:valueTo="@dimen/button_pressed_z_material" android:valueType="floatType"/> <objectAnimator android:propertyName="elevation" android:duration="0" android:valueTo="@dimen/button_elevation_material" android:valueType="floatType"/> </set> </item> <!-- rest state --> <item android:state_enabled=“true” /> <item /> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp
136. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled=“true” /> <!-- rest state --> <item android:state_enabled="true" /> <item /> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp
137. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled=“true” /> <!-- rest state --> <item android:state_enabled="true"> <set> <objectAnimator android:propertyName="translationZ" android:duration="@integer/button_pressed_animation_duration" android:valueTo="0" android:startDelay="@integer/button_pressed_animation_delay" android:valueType="floatType"/> <objectAnimator android:propertyName="elevation" android:duration="0" android:valueTo="@dimen/button_elevation_material" android:valueType="floatType" /> </set> </item> <item /> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp 2dp
138. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled=“true” /> <!-- rest state --> <item android:state_enabled="true"> <set> <objectAnimator android:propertyName="translationZ" android:duration="@integer/button_pressed_animation_duration" android:valueTo="0" android:startDelay="@integer/button_pressed_animation_delay" android:valueType="floatType"/> <objectAnimator android:propertyName="elevation" android:duration="0" android:valueTo="@dimen/button_elevation_material" android:valueType="floatType" /> </set> </item> <item /> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp 2dp
139. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled=“true” /> <!-- rest state --> <item android:state_enabled="true"> <set> <objectAnimator android:propertyName="translationZ" android:duration="@integer/button_pressed_animation_duration" android:valueTo="0" android:startDelay="@integer/button_pressed_animation_delay" android:valueType="floatType"/> <objectAnimator android:propertyName="elevation" android:duration="0" android:valueTo="@dimen/button_elevation_material" android:valueType="floatType" /> </set> </item> <item /> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp 2dp
140. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled=“true” /> <!-- rest state --> <item android:state_enabled=“true” /> <item /> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp 2dp
141. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled=“true” /> <!-- rest state --> <item android:state_enabled=“true” /> <item> <set> <objectAnimator android:propertyName="translationZ" android:duration="0" android:valueTo="0" android:valueType="floatType"/> <objectAnimator android:propertyName="elevation" android:duration="0" android:valueTo="0" android:valueType="floatType"/> </set> </item> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp 2dp 0dp
142. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled=“true” /> <!-- rest state --> <item android:state_enabled=“true” /> <item> <set> <objectAnimator android:propertyName="translationZ" android:duration="0" android:valueTo="0" android:valueType="floatType"/> <objectAnimator android:propertyName="elevation" android:duration="0" android:valueTo="0" android:valueType="floatType"/> </set> </item> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp 2dp 0dp
143. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="true" android:state_enabled=“true” /> <!-- rest state --> <item android:state_enabled=“true” /> <item> <set> <objectAnimator android:propertyName="translationZ" android:duration="0" android:valueTo="0" android:valueType="floatType"/> <objectAnimator android:propertyName="elevation" android:duration="0" android:valueTo="0" android:valueType="floatType"/> </set> </item> </selector> data/res/anim/button_state_list_anim_material.xml 2dp + 6dp 2dp 0dp
144. Takeaways
145. Consistency first!
146. Don’t be afraid to deep dive
147. Buttons are alive!
148. Thanks! CC-by hisgett
149. We are hiring! www.yelp.com/careers/
150. Nicola Corti @cortinico nco@yelp.com @YelpEngineering github.com/yelp yelp.com/careers engineeringblog.yelp.com