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
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)
其他回答
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())
}
}
}
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)
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)
结合上面的答案,我有一个与旧方法兼容的方法startActivityForResult()保持使用requestCode而不改变旧的代码结构:
ActivityLauncher.class
public class ActivityLauncher {
private final ActivityResultLauncher<Intent> launcher;
private ActivityResultCallback<ActivityResult> activityResultCallback;
private ActivityLauncher(@NonNull ActivityResultCaller caller,
@NonNull ActivityResultContract<Intent, ActivityResult> contract,
@Nullable ActivityResultCallback<ActivityResult> activityResultCallback) {
this.activityResultCallback = activityResultCallback;
this.launcher = caller.registerForActivityResult(contract, this::onActivityResult);
}
public static ActivityLauncher registerActivityForResult(
@NonNull ActivityResultCaller caller) {
return new ActivityLauncher(caller, new ActivityResultContracts.StartActivityForResult(), null);
}
public void launch(Intent intent, @Nullable ActivityResultCallback<ActivityResult> activityResultCallback) {
if (activityResultCallback != null) {
this.activityResultCallback = activityResultCallback;
}
launcher.launch(intent);
}
private void onActivityResult(ActivityResult result) {
if (activityResultCallback != null) activityResultCallback.onActivityResult(result);
}
public interface OnActivityResult {
void onActivityResultCallback(int requestCode, int resultCode, Intent data);
}
}
在BaseActivity.java中代码
private final ActivityLauncher activityLauncher = ActivityLauncher.registerActivityForResult(this);
public void startActivityForResult(Intent intent, int requestCode, ActivityLauncher.OnActivityResult onActivityResult) {
activityLauncher.launch(intent, result -> onActivityResult.onActivityResultCallback(requestCode, result.getResultCode(), result.getData()));
}
最后在每个扩展BaseActivity的Activity中,实现ActivityLauncher。将覆盖函数“OnActivityResult”的名称改为“onActivityResultCallback”。还记得删除super.onActivityResult()
如何使用:startActivityForResult(intent, requestCode, this)
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)
}
}