我最近发现onActivityResult已弃用。我们该怎么处理呢?

有什么替代方案吗?


当前回答

另一种方法是分3步完成。(考虑到你有一个startActivityForResult(0和onActivityResult()))

创建一个形式为var resultLauncher的变量:ActivityResultLauncher<Intent> 创建一个私有函数,在其中以这种基本格式初始化resultLauncher

resultLauncher=registerForActivityResult(ActivityResultContracts.StartActivityForResult()){result ->  

// copy paste the code from the onActivityResult replacing resultcode to result.resultCode  

if(result.resultcode==Activity.Result_OK){
val data=result.data // this data variable is of type intent and you can use it 

}else{
//code if you do not get the data 
}
}

使用startActivityForResult()返回行,并将其替换为resultLauncher.launch(intent)

其他回答

下面我来解释一下这种新方法

private val scan =
        registerForActivityResult(ActivityResultContracts.StartActivityForResult())
        { result: ActivityResult ->
            if (result.resultCode == AppCompatActivity.RESULT_OK && result.data != null) {

                var selected_hub = result!!.data!!.getParcelableExtra<ExtendedBluetoothDevice>(Utils.EXTRA_DEVICE)
                Log.d(TAG,"RECONNECT PROCESS "+selected_hub!!.name)
                reconnect(selected_hub!!)

            }
        }

从活动或片段调用此方法

private fun callScan() {
        val intent = Intent(requireActivity(), ScanningMeshDevices::class.java)
        scan.launch(intent)
    }

我使用kotlin扩展,使它非常简单。在你的扩展中添加以下扩展功能。kt文件:

fun AppCompatActivity.startForResult(intent: Intent,
    onResult: (resultCode: Int, data: Intent?) -> Unit
) {
    this.registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {result ->
        onResult(result.resultCode, result.data)
    }.launch(intent)
}

现在,在继承AppCompatActivity的任何活动中,你可以使用下面的简单代码:

val i = Intent(this, TargetActivity::class.java)
startForResult(i) { resultCode, data ->
   //put your code here like:
   if (resultCode == RESULT_OK) {
      //your code here...
      }
   }
}

更新 上述实现可能导致以下异常: java.lang.IllegalStateException: LifecycleOwner xxxx正在尝试注册,而当前状态为恢复。生命周期所有者必须在启动之前调用寄存器。

因此,registerForActivityResult应该提前调用,例如在onCreate之前。这是另一种解决方案。

在你的扩展中添加以下扩展功能。kt文件:

fun AppCompatActivity.registerForResult(onResult: (resultCode: Int, data: Intent?) -> Unit):
        ActivityResultLauncher<Intent> {
    return this.registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
        onResult(result.resultCode, result.data)
    }
}

现在,在继承AppCompatActivity的任何活动中,你可以使用下面的简单代码:

为每个需要结果的操作定义一个类成员变量

private val myActionResult = registerForResult { resultCode, data ->
   //put your code here like:
   if (resultCode == RESULT_OK) {
      //your code here...
      }
   }
}

启动动作

val i = Intent(this, TargetActivity::class.java)
myActionResult.launch(i)

onActivityResult, startActivityForResult, requestPermissions和onRequestPermissionsResult从1.3.0-alpha04开始在androidx.fragment上被弃用,android.app.Activity上没有。 相反,你可以使用registerForActivityResult的活动结果api。

分享我找到的解决方法

首先,使用registerForActivityResult为结果注册这个活动 这将返回一个类型为ActivityResultLauncher<Intent!> 像这样,

private val getResult =
        registerForActivityResult(
            ActivityResultContracts.StartActivityForResult()
        ) {
            if (it.resultCode == Activity.RESULT_OK) {
                val value = it.data?.getStringExtra("input")
            }
        }

现在,无论我们想在哪里启动result活动我们都可以使用getresult。launch(intent)

Kotlin版本的@Muntashir阿肯解决方案

class BetterActivityResult<Input, Result> private constructor(
  caller : ActivityResultCaller,
  contract : ActivityResultContract<Input, Result>,
  var onActivityResult : ((Result) -> Unit)?,
) {

private val launcher : ActivityResultLauncher<Input> =
   caller.registerForActivityResult(contract) { onActivityResult?.invoke(it) }

  /**
   * Launch activity, same as [ActivityResultLauncher.launch] except that it 
   * allows a callback
   * executed after receiving a result from the target activity.
   */
  /**
   * Same as [.launch] with last parameter set to `null`.
   */
  @JvmOverloads
  fun launch(
     input : Input,
     onActivityResult : ((Result) -> Unit)? = this.onActivityResult,
  ) {
    this.onActivityResult = onActivityResult
    launcher.launch(input)
  }

  companion object {
  /**
   * Register activity result using a [ActivityResultContract] and an in-place 
   * activity result callback like
   * the default approach. You can still customise callback using [.launch].
   */
  fun <Input, Result> registerForActivityResult(
    caller : ActivityResultCaller,
    contract : ActivityResultContract<Input, Result>,
    onActivityResult : ((Result) -> Unit)?,
  ) : BetterActivityResult<Input, Result> {
    return BetterActivityResult(caller, contract, onActivityResult)
  }

  /**
   * Same as [.registerForActivityResult] except
   * the last argument is set to `null`.
   */
  fun <Input, Result> registerForActivityResult(
    caller : ActivityResultCaller,
    contract : ActivityResultContract<Input, Result>,
  ) : BetterActivityResult<Input, Result> {
    return registerForActivityResult(caller, contract, null)
  }

  /**
   * Specialised method for launching new activities.
   */
  fun registerActivityForResult(
    caller : ActivityResultCaller,
  ) : BetterActivityResult<Intent, ActivityResult> {
    return registerForActivityResult(caller, StartActivityForResult())
  }
 }
}