How to make Floating Action Button background Gradient?

问题

The code for FAB:

<android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|right|end"
        android:layout_margin="16dp"
        android:src="@drawable/add_chat"
        android:tint="@android:color/white" />
</android.support.design.widget.CoordinatorLayout>

The code for gradient background:

<shape xmlns:android="http://schemas.android.com/apk/res/android" 
android:shape="oval">
<gradient
    android:angle="90"
    android:endColor="#e4849f"
    android:startColor="#d96e30" />
</shape>

android:backgroundTint="" or app:backgroundTint="" both uses color resources only.Can anyone suggest how to do this? Thanks !!

回答1:

Step 1. Create a new drawable.xml and add this code to it

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


        <item>
            <shape xmlns:android="http://schemas.android.com/apk/res/android"
                android:shape="oval">
                <gradient
                    android:type="linear"
                    android:angle="0"
                    android:startColor="#f6ee19"
                    android:endColor="#115ede" />
            </shape>

        </item>
        <item android:gravity="center"
            >
            <bitmap android:src="@drawable/your_icon"
                android:gravity="fill_horizontal" />

        </item>

    </layer-list>

Step 2.) Now in your dimens.xml add this line of code,

<dimen name="design_fab_image_size" tools:override="true">56dp</dimen> 

Step 3.) Finally set this drawable.xml in FAB using *android:src="@drawable/drawable.xml"*

P.S. - Make sure your_icon is a PNG, JPEG.

回答2:

The accepted answer is working fine but after adding the below line, it stretches the icon added on FAB

<dimen name="design_fab_image_size" tools:override="true">56dp</dimen>

I am sharing the screenshots:

Previous FAB button

After adding design_fab_image_size in dimen.xml and adding android:src="@drawable/gradient", the icon get stretched:

To deal with this I replaced my gradient.xml with the following code:

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
    <shape xmlns:android="http://schemas.android.com/apk/res/android"
        android:shape="oval">
        <gradient
            android:angle="90"
            android:startColor="#00FF00"
            android:endColor="#000000" />
        <size
            android:width="56dp"
            android:height="56dp" />
    </shape>
</item>
<item
    android:left="10dp"
    android:right="10dp">
    <shape android:shape="line">
        <stroke
            android:width="2dp"
            android:color="#ffffff" />
    </shape>
</item>
<item
    android:left="10dp"
    android:right="10dp">
    <rotate
        android:fromDegrees="90">
        <shape android:shape="line">
            <stroke
                android:width="2dp"
                android:color="#ffffff" />
        </shape>
    </rotate>
</item>

Output:

回答3:

This method works also. Create a shape called fab_background.xml in drawable where you can do all the customization you want

<?xml version="1.0" encoding="utf-8"?>
<shape android:shape="oval"   xmlns:android="http://schemas.android.com/apk/res/android">
    <size android:width="150dp" android:height="150dp"/>
    <gradient android:startColor="@color/colorAccentDark" android:endColor="@color/colorAccent"/>
</shape>

Create a layout called custom_fab.xml in layout then set the backround and fab icon using the image view

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="50dp"
    android:layout_height="50dp"
    android:gravity="center"
    android:background="@drawable/fab_background"
    >

    <android.appcompat.widget.AppCompatImageView
        android:layout_width="24dp"
        android:layout_height="24dp"
        android:src="@drawable/right" />
</LinearLayout>

You can then reference it using include

Example

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:background="@drawable/background"
    android:orientation="vertical">



    <include layout="@layout/custom_fab"
        android:layout_width="45dp"
        android:layout_height="45dp"
        android:layout_alignParentEnd="true"
        android:layout_alignParentBottom="true"
        android:layout_margin="32dp"/>
</RelativeLayout>

回答4:

No, it is not possible to give a custom drawable or gradient or the FAB icon without breaking the UI guidelines. The icon only accepts backgroundTint to the FAB icon. The UI guidelines clearly states that

Don’t give the floating action button extra dimension.

Read this:Material Guidelines FAB icon

If you still want to implement the gradient on FAB, you could replicate the FAB icon using a simple button and then give gradient color to it.

来源：https://stackoverflow.com/questions/49720287/how-to-make-floating-action-button-background-gradient