参考:Kotlin -从图库中选择图像

迄今为止我发现的最简单的Alernative

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.id.activity_main)

    var ivPhoto = findViewById<ImageView>(R.id.ivPhoto)
    var btnChoosePhoto = findViewById<Button>(R.id.btnChoosePhoto)

    

val getContent = registerForActivityResult(ActivityResultContracts.GetContent())  { uri: Uri? ->
            ivPhoto.setImageURI(uri)    // Handle the returned Uri
        }


    btnChoose.setOnClickListener {
        getContent.launch("image/*")
    }
    
    }

startActivityForResult和onActivityResult在android 10 API 30中已弃用，现在我们有了一种新的方法来使用registerForActivityResult来获得结果

resultContract =
    registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
        if (result.resultCode == Activity.RESULT_OK) {
            // There are no request codes
            val country = result.data?.getParcelableExtra<Country>("Country")
            showLiveDemoDialogue(country)
        }
    }

并启动活动

val intent = Intent(this, CountriesListActivity::class.java)
        resultContract.launch(intent)

但你应该在呼叫发射前注册然后发射到你想去的任何地方。 否则，您将得到这个异常

attempting to register while current state is RESUMED. LifecycleOwners must call register before they are STARTED.

在Java 8中，它可以这样写:

ActivityResultLauncher<Intent> startActivityForResult = registerForActivityResult(
    new ActivityResultContracts.StartActivityForResult(),
    result -> {
        if (result.getResultCode() == AppCompatActivity.RESULT_OK) {
            Intent data = result.getData();
            // ...
        }
    }
);

Intent intent = new Intent( ... );
startActivityForResult.launch(intent);

如果您正在使用SMS同意API，则使用以下代码(Kotlin):

resultLauncher.launch( consentIntent
                            )

    var resultLauncher = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
    if (result.resultCode == Activity.RESULT_OK) {
        // There are no request codes
    //    val data: Intent? = result.data
        val message = result.data?.getStringExtra(SmsRetriever.EXTRA_SMS_MESSAGE)
        getOtpFromMessage(message)

    }
}

从现在开始，startActivityForResult()已经被弃用，所以使用new方法代替。

芬兰湾的科特林的例子

    fun openActivityForResult() {
        startForResult.launch(Intent(this, AnotherActivity::class.java))
    }


    val startForResult = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { 
    result: ActivityResult ->
        if (result.resultCode == Activity.RESULT_OK) {
            val intent = result.data
            // Handle the Intent
            //do stuff here
        }
    }

我想出了如何从Kotlin的片段中正确地做到这一点，以捕获图像并处理返回的位图。在其他情况下也是一样的。

首先，您必须注册片段以侦听活动结果。这必须在初始化片段之前完成，这意味着创建一个成员变量，而不是在onCreate函数中初始化。

class DummyFragment : Fragment() {

  //registering fragment for camera listener
  private val takePhoto = registerForActivityResult(
    ActivityResultContracts.StartActivityForResult()
  ) {
    if (it.resultCode == Activity.RESULT_OK) {
      val imageBitmap = it.data?.extras?.get("data") as Bitmap
      // do your thing with the obtained bitmap
    }
  }

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

}

然后，像你通常做的那样调用摄像机意图。并使用上面创建的变量来启动意图。

override fun onCreate(savedInstanceState: Bundle?) {
  super.onCreate(savedInstanceState)
  someRandomButton.setOnClickListener {
    val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
    takePhoto.launch(takePictureIntent)
  }
}