registerForActivityResult 封装基类

封装完后的用法：

            startForActivityResult(CActivity::class.java){resultCode, data ->
                if(resultCode == Activity.RESULT_OK){
                    val data2 = data.getStringExtra("data2")
                }
            }

使用startActivityForResult的时候，由于有requestCode，我们可以知道data和resultCode从哪个activity里回调回来，但使用registerForActivityResult的时候……

先看看registerForActivityResult的基本用法吧，两个按钮，跳转方式分别为 AAct-->BAct-->AAct   AAct-->CAct-->AAct  

class AActivity : AppCompatActivity() {
    private val startForActivityResult1 = registerForActivityResult(ActivityResultContracts.StartActivityForResult()){
        it.resultCode
        it.data
    }

    private val startForActivityResult2 = registerForActivityResult(ActivityResultContracts.StartActivityForResult()){

    }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        btnJump1.setOnClickListener {
            startForActivityResult1.launch(Intent(this,BActivity::class.java))
        }
        btnJump2.setOnClickListener {
            startForActivityResult2.launch(Intent(this,CActivity::class.java))
        }
    }
}

由于回调数据没有可以识别出是从哪个activity回调,register后回调无法复用，本身又是个final方法，无法重写，所以跳转到每个activity都需要写一次register，使用方法非常的繁琐

这样看似无解，但如果仔细看源码，可以发现回调顺序遵循的是FILO，这就好办了，封装一下：

open class BaseActivity : AppCompatActivity() {
    private val resultCallBacks: Deque<ResultCallBack> = ArrayDeque()
    private val activityForResult =
        registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
            resultCallBacks.pop()?.let {
                it(result.resultCode, result.data?: Intent())
            }
        }

    @JvmOverloads
    protected fun startForActivityResult(
        cls: Class<*>,
        block: Intent.() -> Unit = {},
        callBack: ResultCallBack
    ) {
        resultCallBacks.push(callBack)
        activityForResult.launch(Intent(this, cls).apply(block))
    }

}

使用：

        startForActivityResult(CActivity::class.java, {
            putExtra("data1", "data")
        }) { resultCode, data ->
           
        }

 

本文地址：https://blog.csdn.net/jingzz1/article/details/110236804