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?
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
对于那些具有多个requestCode的片段,并且如果您不确定如何处理这些requestCode的多个结果,那么您需要了解requestCode在新方法中是无用的。
我想象你以前的编码方式是这样的:
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (resultCode == Activity.RESULT_CODE) {
when (requestCode) {
REQUEST_TAKE_PHOTO -> {
// handle photo from camera
}
REQUEST_PICK_IMAGE_FROM_GALLERY -> {
// handle image from gallery
}
}
}
}
在新的API中,你需要在一个单独的ActivityResultContract中实现每个请求的结果:
val takePhotoForResult = registerForActivityResult(StartActivityForResult()) { result: ActivityResult ->
if (result.resultCode == Activity.RESULT_OK) {
val intent = result.data
// handle photo from camera
}
}
val pickImageFromGalleryForResult = registerForActivityResult(StartActivityForResult()) { result: ActivityResult ->
if (result.resultCode == Activity.RESULT_OK) {
val intent = result.data
// handle image from gallery
}
}
然后你需要像这样开始这些活动/意图:
private fun startTakePhotoActivity() {
takePhotoForResult.launch(Intent(requireActivity(), TakePhotoActivity::class.java))
}
private fun pickImageFromGallery() {
val pickIntent = Intent(Intent.ACTION_PICK)
pickIntent.setDataAndType(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
"image/*"
)
pickImageFromGalleryForResult.launch(pickIntent)
}
通过这样做,你可以在你的项目中摆脱数百个const val REQUEST_值。
其他回答
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。
似乎onActivityResult在超类中已弃用,但你在你的问题中没有提到超类名称和compileSdkVersion。
在Java和Kotlin中,只要添加@Deprecated,每个类或方法都可以标记为deprecated,所以检查你的超类,你可能扩展了一个错误的类。
当一个类被弃用时,它的所有方法也被弃用。
要看到一个快速的解决方案,点击弃用的方法,并按Ctrl+Q在Android工作室查看方法的文档,应该有一个解决方案。
在我使用androidx和API 29作为compileSdkVersion的项目中,此方法在活动和片段中不弃用
你可以在developer.android.com上获得基本的培训。
下面是一个关于如何将现有代码转换为新代码的示例:
老办法:
public void openSomeActivityForResult() {
Intent intent = new Intent(this, SomeActivity.class);
startActivityForResult(intent, 123);
}
@Override
protected void onActivityResult (int requestCode, int resultCode, Intent data) {
if (resultCode == Activity.RESULT_OK && requestCode == 123) {
doSomeOperations();
}
}
新方法(Java):
public void openSomeActivityForResult() {
Intent intent = new Intent(this, SomeActivity.class);
someActivityResultLauncher.launch(intent);
}
// You can do the assignment inside onAttach or onCreate, i.e, before the activity is displayed
ActivityResultLauncher<Intent> someActivityResultLauncher = registerForActivityResult(
new ActivityResultContracts.StartActivityForResult(),
new ActivityResultCallback<ActivityResult>() {
@Override
public void onActivityResult(ActivityResult result) {
if (result.getResultCode() == Activity.RESULT_OK) {
// There are no request codes
Intent data = result.getData();
doSomeOperations();
}
}
});
新方法(Kotlin):
fun openSomeActivityForResult() {
val intent = Intent(this, SomeActivity::class.java)
resultLauncher.launch(intent)
}
var resultLauncher = registerForActivityResult(StartActivityForResult()) { result ->
if (result.resultCode == Activity.RESULT_OK) {
// There are no request codes
val data: Intent? = result.data
doSomeOperations()
}
}
编辑。一个更好的方法是使它更一般化,这样我们就可以重用它。下面的代码片段用于我的一个项目,但请注意,它没有经过良好的测试,可能无法涵盖所有情况。
BetterActivityResult.java
import android.content.Intent;
import androidx.activity.result.ActivityResult;
import androidx.activity.result.ActivityResultCaller;
import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContract;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
public class BetterActivityResult<Input, Result> {
/**
* Register activity result using a {@link ActivityResultContract} and an in-place activity result callback like
* the default approach. You can still customise callback using {@link #launch(Object, OnActivityResult)}.
*/
@NonNull
public static <Input, Result> BetterActivityResult<Input, Result> registerForActivityResult(
@NonNull ActivityResultCaller caller,
@NonNull ActivityResultContract<Input, Result> contract,
@Nullable OnActivityResult<Result> onActivityResult) {
return new BetterActivityResult<>(caller, contract, onActivityResult);
}
/**
* Same as {@link #registerForActivityResult(ActivityResultCaller, ActivityResultContract, OnActivityResult)} except
* the last argument is set to {@code null}.
*/
@NonNull
public static <Input, Result> BetterActivityResult<Input, Result> registerForActivityResult(
@NonNull ActivityResultCaller caller,
@NonNull ActivityResultContract<Input, Result> contract) {
return registerForActivityResult(caller, contract, null);
}
/**
* Specialised method for launching new activities.
*/
@NonNull
public static BetterActivityResult<Intent, ActivityResult> registerActivityForResult(
@NonNull ActivityResultCaller caller) {
return registerForActivityResult(caller, new ActivityResultContracts.StartActivityForResult());
}
/**
* Callback interface
*/
public interface OnActivityResult<O> {
/**
* Called after receiving a result from the target activity
*/
void onActivityResult(O result);
}
private final ActivityResultLauncher<Input> launcher;
@Nullable
private OnActivityResult<Result> onActivityResult;
private BetterActivityResult(@NonNull ActivityResultCaller caller,
@NonNull ActivityResultContract<Input, Result> contract,
@Nullable OnActivityResult<Result> onActivityResult) {
this.onActivityResult = onActivityResult;
this.launcher = caller.registerForActivityResult(contract, this::callOnActivityResult);
}
public void setOnActivityResult(@Nullable OnActivityResult<Result> onActivityResult) {
this.onActivityResult = onActivityResult;
}
/**
* Launch activity, same as {@link ActivityResultLauncher#launch(Object)} except that it allows a callback
* executed after receiving a result from the target activity.
*/
public void launch(Input input, @Nullable OnActivityResult<Result> onActivityResult) {
if (onActivityResult != null) {
this.onActivityResult = onActivityResult;
}
launcher.launch(input);
}
/**
* Same as {@link #launch(Object, OnActivityResult)} with last parameter set to {@code null}.
*/
public void launch(Input input) {
launch(input, this.onActivityResult);
}
private void callOnActivityResult(Result result) {
if (onActivityResult != null) onActivityResult.onActivityResult(result);
}
}
使用上述方法,您仍然必须在启动活动或片段附件之前或期间注册它。一旦定义,就可以在活动或片段中重用它。例如,如果你需要在大部分活动中启动新的活动,你可以定义一个BaseActivity并像这样注册一个新的BetterActivityResult:
BaseActivity.java
public class BaseActivity extends AppCompatActivity {
protected final BetterActivityResult<Intent, ActivityResult> activityLauncher = BetterActivityResult.registerActivityForResult(this);
}
之后,你可以简单地从任何子活动中启动一个活动,就像这样:
public void openSomeActivityForResult() {
Intent intent = new Intent(this, SomeActivity.class);
activityLauncher.launch(intent, result -> {
if (result.getResultCode() == Activity.RESULT_OK) {
// There are no request codes
Intent data = result.getData();
doSomeOperations();
}
})
}
因为你可以在Intent的同时设置回调函数,所以你可以在任何活动中重用它。
类似地,您也可以使用其他两个构造函数来使用其他活动契约。
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())
}
}
}
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)