android - 如何在drawable android中添加内阴影效果？

Question

我想像这样将内部阴影效果添加到我的可绘制文件中。

下面是我的可绘制文件。我想在可绘制文件内实现阴影，如上所示。我应该做出哪些改变才能实现这一目标？

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

    <item
        android:bottom="@dimen/_3sdp"
        android:left="@dimen/_8sdp"
        android:right="@dimen/_8sdp"
        android:top="@dimen/_3sdp">

        <shape>

            <corners android:radius="@dimen/_75sdp" />

            <padding android:bottom="@dimen/_8sdp"
                android:top="@dimen/_8sdp" />

            <solid android:color="@color/leave_msg_color" />

        </shape>

    </item>

</layer-list>

Answer 1

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

    <item android:top="@dimen/size_point5dp"
            android:left="@dimen/size_point5dp"
            android:right="@dimen/size_point5dp"
            android:bottom="@dimen/size_point5dp">
        <shape android:shape="rectangle">
            <solid android:color="@color/blue_E7F1FF"/>
            <corners android:radius="8dp"/>
        </shape>

    </item>

    <!--  left shadow -->
    <item>
        <shape android:shape="rectangle">
            <gradient
                    android:angle="180"
                    android:centerColor="#00FF0000"
                    android:centerX="0.98"
                    android:endColor="#5C000000"
                    android:startColor="#00FF0000" />
            <corners android:radius="8dp" />
        </shape>
    </item>
    <!--  right shadow -->
    <item>
        <shape android:shape="rectangle">
            <gradient
                    android:angle="360"
                    android:centerColor="#00FF0000"
                    android:centerX="0.98"
                    android:endColor="#5C000000"
                    android:startColor="#00FF0000" />
            <corners android:radius="8dp" />
        </shape>
    </item>
    <!--  top shadow -->
    <item>
        <shape android:shape="rectangle">
            <gradient
                    android:angle="270"
                    android:centerColor="#00FF0000"
                    android:centerY="0.1"
                    android:endColor="#00FF0000"
                    android:startColor="#6B000000" />
            <corners android:radius="8dp" />
        </shape>
    </item>
 <!--  bottom shadow -->
    <item>
        <shape android:shape="rectangle">
            <gradient
                    android:angle="90"
                    android:centerColor="#00FF0000"
                    android:centerY="0.1"
                    android:endColor="#00FF0000"
                    android:startColor="#6B000000" />
            <corners android:radius="8dp" />
        </shape>
    </item>
</layer-list>

图像看起来像 image