Kotlin中的Android Parcelable:在Parcelable数据类中找不到CREATOR

Question

随着Kotlin RC的发布,我开始编写一个应用程序来学习它但是我无法弄清楚如何开始Parcelable工作.

数据类:

data class Project (val reponame:String,
                val username:String,
                val language:String,
                val vcsUrl:String,
                val branches:Map<String, Branch>) : Parcelable {

    companion object {
        val CREATOR = object : Parcelable.Creator<Project> {
            override fun createFromParcel(`in`: Parcel): Project {
                return Project(`in`)
            }

            override fun newArray(size: Int): Array<Project?> {
                return arrayOfNulls(size)
            }
        }
    }

    protected constructor(parcelIn: Parcel) : this (
            parcelIn.readString(),
            parcelIn.readString(),
            parcelIn.readString(),
            parcelIn.readString(),
            mapOf<String, Branch>().apply {
                parcelIn.readMap(this, Branch::class.java.classLoader)
            }
    )

    override fun describeContents(): Int {
        throw UnsupportedOperationException()
    }

    override fun writeToParcel(dest: Parcel, flags: Int) {
        dest.writeString(reponame)
        dest.writeString(username)
        dest.writeString(language)
        dest.writeString(vcsUrl)
        dest.writeMap(branches)
    }

}

阅读它:

class ProjectDetailActivity : BaseActivity() {

    lateinit var project: Project

    companion object {
        const val EXTRA_PROJECT = "extra_project"
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        project = intent.extras.getParcelable(EXTRA_PROJECT)

        tvTitle.text = project.reponame
    }
}

例外:

Caused by: android.os.BadParcelableException: Parcelable protocol requires a Parcelable.Creator object called CREATOR on class com.eggman.circleciandroid.model.Project
    at android.os.Parcel.readParcelableCreator(Parcel.java:2415)
    at android.os.Parcel.readParcelable(Parcel.java:2337)
    at android.os.Parcel.readValue(Parcel.java:2243)
    at android.os.Parcel.readArrayMapInternal(Parcel.java:2592)
    at android.os.BaseBundle.unparcel(BaseBundle.java:221)
    at android.os.BaseBundle.get(BaseBundle.java:281)
    at com.eggman.circleciandroid.ui.ProjectDetailActivity.onCreate(ProjectDetailActivity.kt:22)

我确信这是一件很简单的事情,我很遗憾,还有其他人在最新的Kotlin上成功使用Parcelable吗？

Kotlin版本:1.0.0-rc-1036

Kotlin插件版本:1.0.0-rc-1036-IJ143-4

代码可以查看@ https://github.com/eggman87/circle-kotlin

Answer 1

Kotlin RC删除了以前弃用的所有伴随对象属性的静态字段生成(在此答案中了解更多信息).

现在只有那些标记的const,lateinit或者@JvmField会产生一个静态字段.

您需要通过注释val CREATOR进行@JvmField注释,因为Android Framework需要CREATOR在您的类中使用静态字段.