java代码

       //大
            GradientDrawable layer1 = new GradientDrawable(GradientDrawable.Orientation.LEFT_RIGHT, new int[]{Color.parseColor("#00f4ff"), Color.parseColor("#43C8FF")});
            layer1.setShape(GradientDrawable.RECTANGLE);
            //小
            GradientDrawable layer2 = new GradientDrawable(GradientDrawable.Orientation.LEFT_RIGHT, new int[]{Color.parseColor("#00f4ff"), Color.parseColor("#43C8FF")});
            layer2.setShape(GradientDrawable.RECTANGLE);
            //阴影
            ColorDrawable layer3 = new ColorDrawable(Color.parseColor("#F0F0F0"));
            layer3.setAlpha(7);
            LayerDrawable layerDrawable = new LayerDrawable(new Drawable[]
                    {layer1, layer2,layer3});
            layerDrawable.setLayerWidth(1, 20);
            layerDrawable.setLayerWidth(2, 20);
            mIvMainBg.setBackground(layerDrawable);

xml

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

    <item>
        <shape android:shape="rectangle">
            <gradient
                android:angle="0"
                android:endColor="#43C8FF"
                android:startColor="#00f4ff" />

        </shape>
    </item>
    <item android:width="16px">
        <shape android:shape="rectangle">
            <gradient
                android:angle="180"
                android:endColor="#00f4ff"
                android:startColor="#43C8FF" />
            <!--            <stroke-->
            <!--                android:color="#00E5F0"-->
            <!--                android:width="1dp"/>-->
        </shape>

    </item>
    <item android:width="20dp">
        <shape android:shape="rectangle">
            <solid android:color="#10F0F0F0" />

        </shape>
    </item>
</layer-list>