效果图

1. 文字渐变

private fun setGradientForTextView(textView: TextView) {
    val endX = textView.paint.textSize * textView.text.length
    val linearGradient = LinearGradient(
        0f, 0f, endX, 0f,
        Color.parseColor("#FFFF68FF"),
        Color.parseColor("#FFFED732"),
        Shader.TileMode.CLAMP
    )
    textView.paint.shader = linearGradient
    textView.invalidate()
}

2. 图片渐变

• 添加仓库并引入依赖库

maven { url 'https://www.jitpack.io' }

implementation 'com.gitee.cxyzy1:AndroidGradientImageView:1.0.0'

• 代码样例

<kr.pe.burt.android.lib.androidgradientimageview.AndroidGradientImageView
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:scaleType="fitXY"
    android:src="@drawable/beauty"
    app:giv_endColor="#f391a9"
    app:giv_endOffset="0.99"
    app:giv_rotate="45.0"
    app:giv_startOffset="0.3" />

3. 背景渐变

• 增加:shape_gradient_bg.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <gradient
        android:angle="270"
        android:centerColor="#f391a9"
        android:endColor="#ef5b9c"
        android:startColor="#f47920" />
    <corners android:radius="0dip" />
</shape>

• 使用

<View
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:background="@drawable/shape_gradient_bg" />

完整源代码

https://gitee.com/cxyzy1/gradient-demos