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
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
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
}
}
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。
我的目标是用最少的代码更改重用startActivityForResult方法的当前实现。为此,我使用onActivityResultFromLauncher方法创建了一个包装器类和接口。
interface ActivityResultLauncherWrapper {
fun launchIntentForResult(activity: FragmentActivity, intent: Intent, requestCode: Int, callBack: OnActivityResultListener)
fun unregister()
interface OnActivityResultListener {
fun onActivityResultFromLauncher(requestCode: Int, resultCode: Int, data: Intent?)
}
}
class ActivityResultLauncherWrapperImpl : ActivityResultLauncherWrapper {
private var weakLauncher: WeakReference<ActivityResultLauncher<Intent>>? = null
override fun launchIntentForResult(
activity: FragmentActivity,
intent: Intent,
requestCode: Int,
callBack: ActivityResultLauncherWrapper.OnActivityResultListener
) {
weakLauncher = WeakReference(
activity.registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
callBack.onActivityResultFromLauncher(requestCode, result.resultCode, result.data)
}
)
weakLauncher?.get()?.launch(intent)
}
override fun unregister() {
weakLauncher?.get()?.unregister()
}
}
我在我的项目中使用匕首,我在需要的地方注入了包装器
@Inject
lateinit var activityResultLauncher: ActivityResultLauncherWrapper
但是包装器也可以直接实例化:
val activityResultLauncher = ActivityResultLauncherWrapper()
然后你必须用launchIntentForResult改变startActivityForResult方法。下面是一个从片段中调用它的例子:
activityResultLauncher.launchIntentForResult(
requireActivity(),
intent,
REQUEST_CODE_CONSTANT,
object: ActivityResultLauncherWrapper.OnActivityResultListener {
override fun onActivityResultFromLauncher(requestCode: Int, resultCode: Int, data: Intent?) {
/*do something*/
}
}
)
您将在匿名对象中收到结果。 你可以在Fragment或FragmentActivity中使用OnActivityResultListener,如果你实现了接口,并像这样重构当前的实现:
class MyFragment : Fragment(), OnActivityResultListener {
...
override fun onActivityResultFromLauncher(requestCode: Int, resultCode: Int, data: Intent?) {/*do somthing*/}
...
}
正如我们所知,Kotlin类ActivityResultLauncherWrapper也可以在java代码中使用。在我的项目中也有java类。这里有一个在Fragment中实现回调接口的例子:
public class MyFragment extends Fragment implements OnActivityResultListener {
...
@Inject
ActivityResultLauncherWrapper activityResultLauncher;
//ActivityResultLauncherWrapper activityResultLauncher = new ActivityResultLauncherWrapper()
...
public void launnchActivity(@NotNull Intent intent) {
activityResultLauncher.launchIntentForResult(requireActivity(), intent, REQUEST_CODE_CONSTANT, this);
}
...
@Override
public void onActivityResultFromLauncher(int requestCode, int resultCode, Intent data) {/*do somthing*/}
...
}
我希望这有助于为您的案例构建解决方案。
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/*")
}
}
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)