Android 干货 --- 丢掉你老旧的参数传递方式，投入 Bracer 的怀抱吧。

//oh shit, wtf!! 写错了 key 的名字，导致一直获取不到值 val valueA = intent.getStringExtra("key_l")

}}再或者，这样？

//Oh my god! 每个 Fragment 都要这么写一遍吗？class FragmentA : Fragment() {var a: String = ""var b: String = ""

companion object {fun newFragment(a: String, b: String): FragmentA {val fragmentA = FragmentA()val bundle = Bundle()bundle.putString("key_a", a)bundle.putString("key_b", b)fragmentA.arguments = bundlereturn fragmentA}}

override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)arguments?.let {a = it.getString("key_a") ?: ""b = it.getString("key_b") ?: ""}}}只是想简单传个参数，写这么多代码真的好累！

没事，现在有了 Bracer，分分钟减轻你的工作量！

来看看新世纪如何正确传递参数！

在 Fragment 中获取参数：

class MutableParamsFragment : Fragment() {//基本类型 var intParams by mutableParams<Int>()var booleanParams by mutableParams<Boolean>()var stringParams by mutableParams<String>()

//自定义类型 var customParams by mutableParams<CustomParams1>()

//listvar intListParams by mutableParams<ArrayList<Int>>()var stringListParams by mutableParams<ArrayList<String>>()

//arrayvar intArrayParams by mutableParams<IntArray>()var arrayCustomParams by mutablePa

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rams<Array<CustomParams1>>()

//其他任意类型//...

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

//直接使用,不需要再手动从 Arguments 中读取了 println(intParams)println(booleanParams)println(stringParams)println(customParams)println(intListParams)println(stringListParams)println(intArrayParams)

}}如你所见，从 Fragment 里获取参数就是这么简单，并且非常安全！！

并且支持几乎所有的类型！

你不会再遇到空指针 null，所有的参数都会有默认值；不会遇到 key 写错的情况，所有的参数默认都以自身的名字作为 key.

等同于：val byteParams = arguments.getByte("byteParams", 0)var stringParams = arguments.getString("stringParams") ?: ""

接下来我们来见识一下如何传递参数：

val fragment = MutableParamsFragment().apply {intParams = 1 //赋值即可 booleanParams = truestringParams = "123"

customParams = CustomParams1()intListParams = arrayListOf(1,2,3)

intArrayParams = IntArray(2) { it }}

//show this Fragmentval beginTransaction = supportFragmentManager.beginTransaction()beginTransaction.add(R.id.frameLayout, fragment, "")beginTransaction.commit()

Amazing!! 是的就是这么神奇，传递参数就是这么简单！

Double Kill 接下来看一下 Activity 的情况吧

class MutableParamsActivity : AppCompatActivity() {//基本类型 var intParams by mutableParams<Int>()var booleanParams by mutableParams<Boolean>()var stringParams by mutableParams<String>()

//自定义类型 var customParams by mutableParams<CustomParams1>()

//listvar intListParams by mutableParams<ArrayList<Int>>()var stringListParams by mutableParams<ArrayList<String>>()

//arrayvar intArrayParams by mutableParams<IntArray>()var arrayCustomParams by mutableParams<Array<CustomParams1>>()