棒棒糖上的Android按钮波纹和棒棒糖前的亮点

Question

Hi so I am little confused and wondering if anyone could point me in the right direction.

Go and use Google Play Store on Lollipop and pre-lollipop

You will see on lollipop that selectable views have the ripple effect.

On pre-lollipo, you get this highlight effect.

How is this done?

At the moment in my app, I have a drawable-v21 directory that contains this selector

It basically does the ripple on top of my background

<?xml version="1.0" encoding="utf-8"?>
<ripple xmlns:android="http://schemas.android.com/apk/res/android"
    android:color="?android:colorControlHighlight">
    <item android:id="@android:id/mask" android:drawable="@android:color/white"/>
    <item android:drawable="@color/colorAccentWith92PercentOpacity"/>
</ripple>

However, other answers say to use

android:background="?attr/selectableItemBackground"

To get the highlight effect on pre-lollipop but this overrides my background. How could i set this on top of my current background?

Also do i have to create a ripple drawable (in drawble-v21) for every kind of button in my app? How would I do this for recycler view items?

What makes this question unique

I do not want ripple for pre-lollipop I am asking how devs efficiently make their button do ripple on lollipop and a hight light effect on pre

Answer 1

Option 1

Define colorControlHighlight in your theme and as long you're using default appcompat-v7 buttons the highlight color should work out-of-the-box.

Option 2

This is an example of how I backported Material button style with a bit of crossfade animation and shadows without using external libraries. May it help you on your way.

Provided the button will be white text over dark background ( @color/control_normal ) with light highlight:

values/themes.xml

Here I'll override default button style for the whole theme:

<style name="AppTheme" parent="Base.AppTheme">
    <item name="buttonStyle">@style/Widget.AppTheme.Button</item>
</style>

values/integers.xml

<!-- Some numbers pulled from material design. -->
<integer name="button_pressed_animation_duration">100</integer>
<integer name="button_pressed_animation_delay">100</integer>

values-v21/styles.xml

Button style for Lollipop which understands theme overlays and uses ripple by default. Let's just have it color the ripple with appropriate paint:

<style name="Widget.AppTheme.Button" parent="Widget.AppCompat.Button">
    <!-- On Lollipop you can define theme via style. -->
    <item name="android:theme">@style/ThemeOverlay.AppTheme.Button</item>
</style>

<style name="ThemeOverlay.AppTheme.Button" parent="ThemeOverlay.AppCompat.Dark">
    <!-- The magic is done here. -->
    <item name="colorButtonNormal">@color/control_normal</item>
</style>

values/styles.xml

Before Lollipop it gets tricky.

<style name="Widget.AppTheme.Button" parent="Widget.AppCompat.Button">
    <item name="android:background">@drawable/button_normal_background</item>
</style>

drawable/button_normal_background.xml

Thi is the composite drawable of the whole button.

<inset
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:insetLeft="@dimen/abc_button_inset_horizontal_material"
    android:insetTop="@dimen/abc_button_inset_vertical_material"
    android:insetRight="@dimen/abc_button_inset_horizontal_material"
    android:insetBottom="@dimen/abc_button_inset_vertical_material">
    <layer-list>
        <!-- Shadow. -->
        <item
            android:drawable="@drawable/button_shadow"
            android:top="-0dp"
            android:bottom="-1dp"
            android:left="-0dp"
            android:right="-0dp"/>
        <item
            android:drawable="@drawable/button_shadow_pressable"
            android:top="-0dp"
            android:bottom="-3dp"
            android:left="-1dp"
            android:right="-1dp"/>
        <!-- Background. -->
        <item android:drawable="@drawable/button_shape_normal"/>
        <!-- Highlight. -->
        <item>
            <selector
                android:enterFadeDuration="@integer/button_pressed_animation_duration"
                android:exitFadeDuration="@integer/button_pressed_animation_duration">

                <item
                    android:drawable="@drawable/button_shape_highlight"
                    android:state_focused="true"
                    android:state_enabled="true"/>
                <item
                    android:drawable="@drawable/button_shape_highlight"
                    android:state_pressed="true"
                    android:state_enabled="true"/>
                <item
                    android:drawable="@drawable/button_shape_highlight"
                    android:state_selected="true"
                    android:state_enabled="true"/>
                <item android:drawable="@android:color/transparent"/>
            </selector>
        </item>
        <!-- Inner padding. -->
        <item android:drawable="@drawable/button_padding"/>
    </layer-list>
</inset>

drawable/button_shadow.xml

This is the shadow when not pressed.

<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <corners
        android:bottomLeftRadius="3dp"
        android:bottomRightRadius="3dp"
        android:topLeftRadius="2dp"
        android:topRightRadius="2dp"/>
  <solid android:color="#2000"/>
</shape>

drawable/button_shadow_pressable.xml

This is the extended shadow in pressed state. The result effect will look crude when you look up close but it's good enough from distance.

<selector
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    tools:ignore="UnusedAttribute"
    android:enterFadeDuration="@integer/button_pressed_animation_duration"
    android:exitFadeDuration="@integer/button_pressed_animation_duration">
    <item
        android:state_pressed="true"
        android:state_enabled="true">
        <shape
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:shape="rectangle">
            <corners
                android:bottomLeftRadius="5dp"
                android:bottomRightRadius="5dp"
                android:topLeftRadius="3dp"
                android:topRightRadius="3dp"/>
            <solid android:color="#20000000"/>
        </shape>
    </item>
    <item android:drawable="@android:color/transparent"/>
</selector>

drawable/button_shape_normal.xml

This is the main button shape.

<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <corners android:radius="@dimen/abc_control_corner_material"/>
    <solid android:color="@color/control_normal"/>
</shape>

drawable/button_padding.xml

Just additional padding to be absolutely consistent with the Material button.

<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <solid android:color="@android:color/transparent"/>
    <padding
        android:left="@dimen/abc_button_padding_horizontal_material"
        android:top="@dimen/abc_button_padding_vertical_material"
        android:right="@dimen/abc_button_padding_horizontal_material"
        android:bottom="@dimen/abc_button_padding_vertical_material"/>
</shape>

drawable/button_shape_highlight.xml

This is the highlight button shape drawn over normal button shape.

<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <corners android:radius="@dimen/abc_control_corner_material"/>
    <solid android:color="@color/control_highlight"/>
</shape>

@color/control_highlight can point to

• @color/ripple_material_dark - translucent white, use over dark background
• @color/ripple_material_light - translucent black, use over light background
• Any other color you define.

Answer 2

You can set a background of your views in this way:

android:background="@drawable/touch_selector"

Create a version without ripple for pre lollipop: drawable/touch_selector.xml

<?xml version="1.0" encoding="utf-8"?>

<selector xmlns:android="http://schemas.android.com/apk/res/android">  
    <!-- State when a row is being pressed, but hasn't yet been activated (finger down) -->
    <item android:state_pressed="true"
        android:drawable="@color/grey"
        />

    <!-- For ListView in SINGLE_CHOICE_MODE, it flags the active row -->
    <item android:state_activated="true"
          android:drawable="@color/light_green" />

    <!-- Default, "just hangin' out" state. -->
    <item android:drawable="@android:color/transparent" />
</selector>

Now do the same for lollipop and above, but with ripple effect:
crete drawable-v21/touch_selector.xml

It will look like:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <!-- State when a row is being pressed, but hasn't yet been activated (finger down) -->
    <item android:state_pressed="true">
        <ripple android:color="@color/grey" />
    </item>

    <!-- For ListView, when the view is "activated".  In SINGLE_CHOICE_MODE, it flags the active row -->
    <item android:state_activated="true"
          android:drawable="@color/light_green" />

    <!-- Default, "just hangin' out" state. -->
    <item android:drawable="@android:color/transparent" />
</selector>

That's it.
Now you are having ripple effect at lollipop and above devices and highlight at pre lollipop.

Edit:
In case of using in a ListView - use created above as a background of ListView item