Android Button's background as shape with Shad

问题:

I've made a button background from shapes and is looking quite good for my purpose. The only thing needed is to drop a bit of shadow for it. Here is the code:

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

    <item android:state_pressed="true">
        <shape>
            <solid android:color="#343434" />

            <stroke android:width="1dp" android:color="#171717" />

            <corners android:radius="3dp" />

            <padding android:bottom="10dp" android:left="10dp" android:right="10dp" android:top="10dp" />
        </shape>
    </item>
    <item>
        <shape>
            <gradient android:angle="270" android:endColor="#E2E2E2" android:startColor="#BABABA" />

            <stroke android:width="1dp" android:color="#BABABA" />

            <corners android:radius="4dp" />

            <padding android:bottom="10dp" android:left="10dp" android:right="10dp" android:top="10dp" />
        </shape>
   </item>

</selector>

Here's what I want to achieve

How do I drop the shadow ? My guess is that I need to make another shape but with black/gray background and set some sort of topa nd left padding of margin to make it look like a shadow. But I don't know how to do it... and documentation didn't helped me too much.

Later Edit: I want to add the shadow in xml file and not by code. Thanks.

回答1:

If you want to stack more shapes one on top of each other then you could use a layer-list. Bellow is the code for the normal item in your selector(with a strip of gray color):

<item>
    <layer-list>
        <item android:right="5dp" android:top="5dp">
            <shape>
                <corners android:radius="3dp" />
                <solid android:color="#D6D6D6" />
            </shape>
        </item>
        <item android:bottom="2dp" android:left="2dp">
            <shape>
                <gradient android:angle="270" android:endColor="#E2E2E2" android:startColor="#BABABA" />
                <stroke android:width="1dp" android:color="#BABABA" />
                <corners android:radius="4dp" />
                <padding android:bottom="10dp" android:left="10dp" android:right="10dp" android:top="10dp" />
            </shape>
        </item>
    </layer-list>
</item>

The problem is that you'll not be able to achieve a true shadow look on your Button with this type of drawable. You could use the code from the other answer or a nine patch image that already has shadow on it.

回答2:

Try this...

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
    <item>
        <shape>
            <solid android:color="#000000" />

            <corners android:radius="7dp" />
        </shape>
    </item>
    <item
        android:bottom="5px"
        android:left="5px">
        <shape>
            <solid android:color="#FF0000" />

            <corners android:radius="7dp" />
        </shape>
    </item>
</layer-list>

回答3:

Paint mShadow = new Paint(); 
// radius=10, y-offset=2, color=black 
mShadow.setShadowLayer(10.0f, 0.0f, 2.0f, 0xFF000000); 
// in onDraw(Canvas) 
canvas.drawBitmap(bitmap, 0.0f, 0.0f, mShadow);

This code is from Android's Romain Guy available here : http://www.devoxx.com/download/attachments/1705921/D8_C_10_09_04.pdf

回答4:

You may try this:

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<!-- Bottom Shadow Darker Line--> 
<item>
    <shape android:shape="rectangle" >
        <solid android:color="@color/blue_darker" />
        <corners android:radius="9dip" />
    </shape>
</item>    


<!-- Main Content Gradient -->
<item android:bottom="1dip">
    <shape android:shape="rectangle" android:dither="false" >
        <gradient
            android:startColor="@color/blue_dark"
            android:centerColor="@color/blue_medium"
            android:endColor="@color/blue_light"
            android:type="linear"
            android:angle="90"/>
        <corners android:radius="9dip" />
    </shape>
</item>

<!-- Upper Shadow Dark Line -->
<item android:bottom="1dip" android:left="1dip" android:right="1dip">
     <shape android:shape="rectangle" >
        <gradient
            android:centerX="0.98"
            android:centerY="0"
            android:startColor="@android:color/transparent"
            android:centerColor="@android:color/transparent"
            android:endColor="@color/blue_medium"
            android:type="linear"
            android:angle="90"/>            
        <corners android:radius="9dip" />
    </shape>
</item>    

回答5:

you can try the following code also to get a smooth border shadow for view:

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >

<item>
    <shape>
        <solid android:color="#88000000" />

        <corners android:radius="15dp" />
    </shape>
</item>
<item
    android:bottom="5px"
    android:right="5px">
    <shape>
        <solid android:color="#55B0CF" />

        <stroke
            android:width="2dp"
            android:color="#ffffff" />

        <corners android:radius="7dp" />
    </shape>
</item>

回答6:

In this case I use lib https://github.com/dmytrodanylyk/shadow-layout

Firstly, you should turn on it in gradle

dependencies {
    compile 'com.github.dmytrodanylyk.shadow-layout:library:1.0.3'
}

then put your Button into ShadowLayout

<com.dd.ShadowLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:sl_shadowRadius="3dp"
        app:sl_shadowColor="@color/your_color">
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </com.dd.ShadowLayout>

It's worsk great for me)