Android Studios：类型推断失败。类型参数 T 的值应该在输入类型中提到

Question

Android Studios (Kotlin) 出错

错误：

e：类型推断失败。类型参数 T 的值应在输入类型（参数类型、接收者类型或预期类型）中提及。尝试明确指定它。

fun devId(): Any {
    var str = Build.CPU_ABI
    if (Build.VERSION.SDK_INT >= 21) {
        var i = 0
        val hashSet = HashSet(listOf(arrayOf("armeabi", "armeabi-v7a", "arm64-v8a", "x86", "x86_64", "mips", "mips64")))
        val strArr = Build.SUPPORTED_ABIS
        val length = strArr.size
        while (true) {
            if (i >= length) { break }
            val str2 = strArr[i]
            if (hashSet.contains(str2)) {
                str = str2
                break
            }
            i++
        }
    }
    return println(Build.BOARD + Build.BRAND + str + Build.DEVICE + Build.MANUFACTURER + Build.MODEL + Build.PRODUCT)
}

Answer 1

问题出在hashSet.contains(str2)。这个表达式总是错误的。因为hashSet 类型是HashSet<Array<String>> 但str2 是String 你可以传递给函数contains 只有Array<String>

看起来你可以将你的代码重写为：

fun devId() {
    val str = if (Build.VERSION.SDK_INT >= 21) {
        Build.SUPPORTED_ABIS
            .firstOrNull { it in setOf("armeabi", "armeabi-v7a", "arm64-v8a", "x86", "x86_64", "mips", "mips64") }
            ?: Build.CPU_ABI
    } else Build.CPU_ABI

    return println(Build.BOARD + Build.BRAND + str + Build.DEVICE + Build.MANUFACTURER + Build.MODEL + Build.PRODUCT)
}