使用 Gson.fromJson 时，致命信号 11 (SIGSEGV)，代码 128，tid 12680 中的故障地址 0x0答案

【问题标题】：Fatal signal 11 (SIGSEGV), code 128, fault addr 0x0 in tid 12680 when using Gson.fromJson使用 Gson.fromJson 时，致命信号 11 (SIGSEGV)，代码 128，tid 12680 中的故障地址 0x0
【发布时间】：2020-02-12 09:42:09
【问题描述】：

我的应用程序崩溃了，除了出现此错误之外没有任何堆栈跟踪：

A/libc: Fatal signal 11 (SIGSEGV), code 128, fault addr 0x0 in tid 12680 (dio.downloadapp)

经过一些故障排除后，我将其范围缩小到这一行作为导致此错误的原因：

val details = gson.fromJson(fileReader, VideoDetails::class.java)

它来自视图模型的方法：

private fun onVideoDetailsFetched() {
            try {
                val file = File(context.filesDir, QUEUE_VIDEO_DETAILS_FILE)
                val fileReader = FileReader(file)
                val details = gson.fromJson(fileReader, VideoDetails::class.java)
                videoDetails.send(details)
            } catch (e: Exception) {
                e.printStackTrace()
            }
        }

该文件是在 WorkManager 库中的 Worker 类的方法中创建的：

    private fun VideoDetails.saveVideoDetails() {
        val json = gson.toJson(this)
        File(applicationContext.filesDir, VIDEO_DETAILS_FILE).writeText(json)
    }

还有VideoDetails只是一个数据类，有一堆字符串和一个位图：

data class VideoDetails(
        val filename: String? = null,
        val title: String? = null,
        val vcodec: String? = null,
        val acodec: String? = null,
        val duration: String? = null,
        val filesize: String? = null,
        val width: String? = null,
        val height: String? = null,
        val bitrate: String? = null,
        val framerate: String? = null,
        val encoder: String? = null,
        val encodedBy: String? = null,
        val date: String? = null,
        val creationTime: String? = null,
        val artist: String? = null,
        val album: String? = null,
        val albumArtist: String? = null,
        val track: String? = null,
        val genre: String? = null,
        val composer: String? = null,
        val performer: String? = null,
        val copyright: String? = null,
        val publisher: String? = null,
        val language: String? = null,
        var thumbnail: Bitmap? = null
)

奇怪的是，只有在第三次调用 Gson.fromJson() 时才会发生崩溃。前两次，它工作正常。

有人知道我为什么会收到这个错误吗？又该如何解决呢？

更新：

当我删除位图时，它似乎可以工作。现在，问题是如何存储位图并使其工作。

【问题讨论】：

标签： android kotlin gson android-bitmap

【解决方案1】：

造成这种情况的根本原因是VideoDetails 数据类中的位图。显然，Gson 不能处理位图。我决定为VideoDetails 创建一个自定义TypeAdapter，而不是删除位图。这样我就不必更改VideoDetails 类，因此我不必更改我的代码的许多部分。

完整代码：

class VideoDetailsTypeAdapter : TypeAdapter<VideoDetails?>() {
    override fun write(out: JsonWriter?, value: VideoDetails?) {
        value?.apply {
            out?.apply {
                beginObject()
                filename?.let { name(FILENAME).value(it) }
                title?.let { name(TITLE).value(it) }
                vcodec?.let { name(VCODEC).value(it) }
                acodec?.let { name(ACODEC).value(it) }
                duration?.let { name(DURATION).value(it) }
                filesize?.let { name(FILESIZE).value(it) }
                width?.let { name(WIDTH).value(it) }
                height?.let { name(HEIGHT).value(it) }
                bitrate?.let { name(BITRATE).value(it) }
                framerate?.let { name(FRAMERATE).value(it) }
                encoder?.let { name(ENCODER).value(it) }
                encodedBy?.let { name(ENCODED_BY).value(it) }
                date?.let { name(DATE).value(it) }
                creationTime?.let { name(CREATION_TIME).value(it) }
                artist?.let { name(ARTIST).value(it) }
                album?.let { name(ALBUM).value(it) }
                albumArtist?.let { name(ALBUM_ARTIST).value(it) }
                track?.let { name(TRACK).value(it) }
                genre?.let { name(GENRE).value(it) }
                composer?.let { name(COMPOSER).value(it) }
                performer?.let { name(PERFORMER).value(it) }
                copyright?.let { name(COPYRIGHT).value(it) }
                publisher?.let { name(PUBLISHER).value(it) }
                language?.let { name(LANGUAGE).value(it) }
                thumbnail?.let {
                    name(THUMBNAIL).beginArray()
                    val pixelInts = IntArray(it.width * it.height)
                    it.getPixels(pixelInts, 0, it.width, 0, 0, it.width, it.height)
                    val storeInts = IntArray(pixelInts.size + 2)
                    pixelInts.copyInto(storeInts, 0, 0, pixelInts.size)
                    storeInts[storeInts.size - 2] = it.width
                    storeInts[storeInts.size - 1] = it.height
                    for (int in storeInts)
                        value(int)
                    endArray()
                }
                endObject()
            }
        }
    }

    override fun read(`in`: JsonReader?): VideoDetails? {
        return `in`?.run {
            beginObject()
            val entries = Array<String?>(24) { null }
            var thumbnail: Bitmap? = null
            while (hasNext()) {
                when (nextName()) {
                    FILENAME -> entries[0] = nextString()
                    TITLE -> entries[1] = nextString()
                    VCODEC -> entries[2] = nextString()
                    ACODEC -> entries[3] = nextString()
                    DURATION -> entries[4] = nextString()
                    FILESIZE -> entries[5] = nextString()
                    WIDTH -> entries[6] = nextString()
                    HEIGHT -> entries[7] = nextString()
                    BITRATE -> entries[8] = nextString()
                    FRAMERATE -> entries[9] = nextString()
                    ENCODER -> entries[10] = nextString()
                    ENCODED_BY -> entries[11] = nextString()
                    DATE -> entries[12] = nextString()
                    CREATION_TIME -> entries[13] = nextString()
                    ARTIST -> entries[14] = nextString()
                    ALBUM -> entries[15] = nextString()
                    ALBUM_ARTIST -> entries[16] = nextString()
                    TRACK -> entries[17] = nextString()
                    GENRE -> entries[18] = nextString()
                    COMPOSER -> entries[19] = nextString()
                    PERFORMER -> entries[20] = nextString()
                    COPYRIGHT -> entries[21] = nextString()
                    PUBLISHER -> entries[22] = nextString()
                    LANGUAGE -> entries[23] = nextString()
                    THUMBNAIL -> {
                        beginArray()
                        val intList = mutableListOf<Int>()
                        while (hasNext())
                            intList.add(nextInt())
                        endArray()
                        val storeInts = intList.toIntArray()
                        val pixelInts = IntArray(storeInts.size - 2)
                        storeInts.copyInto(pixelInts, 0, 0, storeInts.size - 2)
                        val width = storeInts[storeInts.size - 2]
                        val height = storeInts[storeInts.size - 1]
                        thumbnail = Bitmap.createBitmap(pixelInts, width, height, Bitmap.Config.ARGB_8888)
                    }
                }
            }
            endObject()
            VideoDetails(
                    entries[0],
                    entries[1],
                    entries[2],
                    entries[3],
                    entries[4],
                    entries[5],
                    entries[6],
                    entries[7],
                    entries[8],
                    entries[9],
                    entries[10],
                    entries[11],
                    entries[12],
                    entries[13],
                    entries[14],
                    entries[15],
                    entries[16],
                    entries[17],
                    entries[18],
                    entries[19],
                    entries[20],
                    entries[21],
                    entries[22],
                    entries[23],
                    thumbnail
            )
        }
    }

    companion object {
        const val FILENAME = "filename"
        const val TITLE = "title"
        const val VCODEC = "vcodec"
        const val ACODEC = "acodec"
        const val DURATION = "duration"
        const val FILESIZE = "filesize"
        const val WIDTH = "width"
        const val HEIGHT = "height"
        const val BITRATE = "bitrate"
        const val FRAMERATE = "framerate"
        const val ENCODER = "encoder"
        const val ENCODED_BY = "encodedBy"
        const val DATE = "date"
        const val CREATION_TIME = "creationTime"
        const val ARTIST = "artist"
        const val ALBUM = "album"
        const val ALBUM_ARTIST = "albumArtist"
        const val TRACK = "track"
        const val GENRE = "genre"
        const val COMPOSER = "composer"
        const val PERFORMER = "performer"
        const val COPYRIGHT = "copyright"
        const val PUBLISHER = "publisher"
        const val LANGUAGE = "language"
        const val THUMBNAIL = "thumbnail"
    }
}

位图被简单地转换为IntArray，然后包含位图中每个像素的 Int 值以及位图的宽度和高度作为该数组的最后两个条目。然后将此IntArray 转换为Json。将其转换回位图只是将这个过程颠倒过来。

以下代码将自定义TypeAdapter注册到Gson。

    private val gson = GsonBuilder()
            .registerTypeAdapter(VideoDetails::class.java, VideoDetailsTypeAdapter())
            .create()

【讨论】：