将 库 编译成aar

1、生成aar

2、在项目中引用

3、gradle 中写入：

    implementation fileTree(include: ['*.jar', '*.aar'], dir: 'libs')
    androidTestImplementation('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    // 支付宝 SDK AAR 包所需的配置
    implementation files('libs/alipaySdk-15.6.2-20190416165036.aar')
    // 图片浏览
    implementation files('libs/mango-release.aar')
    // 图片选择
    implementation files('libs/imagepicker-release.aar')