Moshi 之HashMap

就是这个错 moshi让你写自定义Adapter呢，

报错摘要：

No JsonAdapter for class java.util.HashMap, you should probably use Map instead of HashMap (Moshi only supports the collection interfaces by default) or else register a custom JsonAdapter.

解决方法

自定义 HashMap Adapter代码如下

class HashMapJsonAdapter<K, V>(moshi: Moshi, keyType: Type?, valueType: Type?) :
    JsonAdapter<HashMap<K?, V?>?>() {
    private val keyAdapter: JsonAdapter<K>
    private val valueAdapter: JsonAdapter<V>

    @Throws(IOException::class)
    override fun toJson(writer: JsonWriter, value: HashMap<K?, V?>?) {
        writer.beginObject()
        for (entry: Map.Entry<K?, V?> in value!!.entries) {
            if (entry.key == null) {
                throw JsonDataException("Map key is null at " + writer.path)
            }
            writer.promoteValueToName()
            keyAdapter.toJson(writer, entry.key)
            valueAdapter.toJson(writer, entry.value)
        }
        writer.endObject()
    }

    @Throws(IOException::class)
    override fun fromJson(reader: JsonReader): HashMap<K?, V?> {
        val result = HashMap<K?, V?>()
        reader.beginObject()
        while (reader.hasNext()) {
            reader.promoteNameToValue()
            val name = keyAdapter.fromJson(reader)
            val value = valueAdapter.fromJson(reader)
            val replaced = result.put(name, value)
            if (replaced != null) {
                throw JsonDataException(
                    "Map key '"
                            + name
                            + "' has multiple values at path "
                            + reader.path
                            + ": "
                            + replaced
                            + " and "
                            + value
                )
            }
        }
        reader.endObject()
        return result
    }

    override fun toString(): String {
        return "JsonAdapter($keyAdapter=$valueAdapter)"
    }

    companion object {
        val FACTORY: Factory =
            Factory { type, annotations, moshi ->
                val rawType = Types.getRawType(type)
                if (annotations.isNotEmpty()) return@Factory null
                if (rawType != java.util.HashMap::class.java) return@Factory null
                val keyAndValue = if (type === java.util.Properties::class.java) arrayOf<Type>(
                    String::class.java,
                    String::class.java
                ) else {
                    arrayOf<Type>(Any::class.java, Any::class.java)
                }
                HashMapJsonAdapter<Any?, Any>(
                    moshi,
                    keyAndValue[0],
                    keyAndValue[1]
                ).nullSafe()
            }
    }

    init {
        keyAdapter = moshi.adapter(keyType)
        valueAdapter = moshi.adapter(valueType)
    }
}

其实完全就是在抄Moshi的MapJsonAdapter 然后略微修改一下FACTORY。

如何使用

Moshi.Builder()
    .add(HashMapJsonAdapter.FACTORY)
    .build()

完美解决