我正在使用android库androidx.appcompat:appcompat:1.0.2。在一个代码实验室工作经理的样本上工作。我需要从ViewModel获取实时数据,而我正在使用它
mViewModel!!.getOutputWorkInfo()?.observe(this, Observer<List<WorkInfo>> {
})
但是这个变量显示错误-
类型不匹配。必需:生命周期所有者。找到:BlurActivity
我用谷歌搜索表示不需要扩展生命周期所有者,默认情况下,appcompact Activity 会实现生命周期所有者。
我也在另一个项目中进行了此工作,但未发现任何问题。我不知道为什么我在这个项目中遇到这个错误。
`
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.ImageView
import android.widget.ProgressBar
import android.widget.RadioGroup
import com.bumptech.glide.Glide
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProviders
import androidx.work.WorkInfo
class BlurActivity : AppCompatActivity() {
private var mViewModel: BlurViewModel? = null
private var mImageView: ImageView? = null
private var mProgressBar: ProgressBar? = null
private var mGoButton: Button? = null
private var mOutputButton: Button? = null
private var mCancelButton: Button? = null
/**
* Get the blur level from the radio button as an integer
* @return Integer representing the amount of times to blur the image
*/
private val blurLevel: Int
get() {
val radioGroup = findViewById<RadioGroup>(R.id.radio_blur_group)
return when (radioGroup.checkedRadioButtonId) {
R.id.radio_blur_lv_1 -> 1
R.id.radio_blur_lv_2 -> 2
R.id.radio_blur_lv_3 -> 3
else -> 1
}
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_blur)
// Get the ViewModel
mViewModel = ViewModelProviders.of(this).get(BlurViewModel::class.java)
// Get all of the Views
mImageView = findViewById(R.id.image_view)
mProgressBar = findViewById(R.id.progress_bar)
mGoButton = findViewById(R.id.go_button)
mOutputButton = findViewById(R.id.see_file_button)
mCancelButton = findViewById(R.id.cancel_button)
// Image uri should be stored in the ViewModel; put it there then display
val intent = intent
val imageUriExtra = intent.getStringExtra(Constants.KEY_IMAGE_URI)
mViewModel!!.setImageUri(imageUriExtra)
if (mViewModel!!.imageUri != null) {
Glide.with(this).load(mViewModel!!.imageUri).into(mImageView!!)
}
mViewModel!!.getOutputWorkInfo()?.observe(this, Observer<List<WorkInfo>> {
// If there are no matching work info, do nothing
if (it == null || it.isEmpty()) return@Observer
// We only care about the first output status.
// Every continuation has only one worker tagged TAG_OUTPUT
val workInfo = it[0]
val finished = workInfo.state.isFinished
if (!finished) showWorkInProgress() else showWorkFinished()
})
// Setup blur image file button
mGoButton!!.setOnClickListener { view -> mViewModel!!.applyBlur(blurLevel) }
}
/**
* Shows and hides views for when the Activity is processing an image
*/
private fun showWorkInProgress() {
mProgressBar!!.visibility = View.VISIBLE
mCancelButton!!.visibility = View.VISIBLE
mGoButton!!.visibility = View.GONE
mOutputButton!!.visibility = View.GONE
}
/**
* Shows and hides views for when the Activity is done processing an image
*/
private fun showWorkFinished() {
mProgressBar!!.visibility = View.GONE
mCancelButton!!.visibility = View.GONE
mGoButton!!.visibility = View.VISIBLE
}
}
`
最佳答案
同样的问题在这里,所以我不得不更新我的androidx.appcompat依赖项,如下所示:
implementation 'androidx.appcompat:appcompat:1.1.0-alpha04'
无需实现
LifecycleOwner
(因为默认情况下现在实现了{如Darthcow所述)}