未找到 Android 绑定适配器属性

Question

I am using a binding adapter to have mutable text in one of my views. I believe I have it implemented correctly (and it's working in other places), but for the case of mutableText, it's getting the error AAPT: error: attribute mutableText not found

I've looked through some other answers on here, but none of them have been able to solve the issue.

Here is my layout file:

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <data>
        <variable
            name="viewModel"
            type="com.example.nhlstats.ui.game.GameViewModel" />
    </data>
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <LinearLayout
            android:id="@+id/awayTeam"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:layout_marginTop="12dp">

            <ImageView
                android:id="@+id/awayTeamLogo"
                android:layout_height="48dp"
                android:layout_width="0dp"
                android:layout_weight="1"
                tools:src="@drawable/ic_launcher_background"/>

            <TextView
                android:id="@+id/awayTeamName"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="3"
                android:layout_gravity="center_vertical"
                app:mutableText="@{viewModel.getAwayTeamName()}"
                tools:text="CHI Blackhawks"/>

            <TextView
                android:id="@+id/awayScore"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:layout_gravity="center_vertical"
                app:mutableText="@{viewModel.getAwayTeamScore().toString()}"
                tools:text="0"/>
            <TextView

                android:id="@+id/gameTime"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:layout_gravity="center_vertical"
                app:mutableText="@{viewModel.getTimeRemaining()"
                tools:text="14:26 3rd"/>

        </LinearLayout>

        <LinearLayout
            android:id="@+id/homeTeam"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="12dp">

            <ImageView
                android:id="@+id/homeTeamLogo"
                android:layout_height="48dp"
                android:layout_width="0dp"
                android:layout_weight="1"
                tools:src="@drawable/ic_launcher_background"/>

            <TextView
                android:id="@+id/homeTeamName"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="3"
                android:layout_gravity="center_vertical"
                app:mutableText="@{viewModel.getHomeTeamName()}"
                tools:text="CAR Hurricanes"/>

            <TextView
                android:id="@+id/homeScore"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center_vertical"
                android:layout_weight="2"
                app:mutableText="@{viewModel.getHomeTeamScore().toString()}"
                tools:text="4"/>
        </LinearLayout>
    </LinearLayout>
</layout>

and my BindingAdpater function:

@BindingAdapter("mutableText")
fun setMutableText(view: TextView, text: MutableLiveData<String>?) {
    val parentActivity:AppCompatActivity? = view.getParentActivity()
    if (parentActivity != null && text != null) {
        text.observe(parentActivity, Observer { value ->
            view.text = value?:""
        })
    }
}

GameViewModel:

class GameViewModel:BaseViewModel() {
    private val awayTeamName = MutableLiveData<String>()
    private val homeTeamName = MutableLiveData<String>()
    private val awayTeamScore = MutableLiveData<Int>()
    private val homeTeamScore = MutableLiveData<Int>()
    private val timeRemaining = MutableLiveData<String>()

    fun bind(response: Game) {
        awayTeamName.value = response.gameData.teams.get(0).name
        homeTeamName.value = response.gameData.teams.get(1).name
        awayTeamScore.value = response.liveData.linescore.teams.get(1).goals
        homeTeamScore.value = response.liveData.linescore.teams.get(0).goals
        timeRemaining.value = response.liveData.linescore.currentPeriodOrdinal + " " + response.liveData.linescore.currentPeriodTimeRemaining
    }

    fun getAwayTeamName(): MutableLiveData<String> {
        return awayTeamName
    }

    fun getHomeTeamName(): MutableLiveData<String> {
        return homeTeamName
    }

    fun getAwayTeamScore(): MutableLiveData<Int> {
        return awayTeamScore
    }

    fun getHomeTeamScore(): MutableLiveData<Int> {
        return homeTeamScore
    }

    fun getTimeRemaining(): MutableLiveData<String> {
        return timeRemaining
    }
}

MainActivity:

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding
    private lateinit var viewModel: GameListViewModel
    private var errorSnackbar: Snackbar? = null

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

        binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
        binding.gameList.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)

        viewModel = ViewModelProviders.of(this).get(GameListViewModel::class.java)
        viewModel.errorMessage.observe(this, Observer { errorMessage ->
            if (errorMessage != null)
                showError(errorMessage)
            else
                hideError()
        })
        binding.viewModel = viewModel
    }

    private fun showError(@StringRes errorMessage:Int) {
        errorSnackbar = Snackbar.make(binding.root, errorMessage, Snackbar.LENGTH_INDEFINITE)
        errorSnackbar?.setAction(R.string.retry, viewModel.errorClickListener)
        errorSnackbar?.show()
    }

    private fun hideError() {
        errorSnackbar?.dismiss()
    }
}

Thanks in advance.

Answer 1

Your binding adapter receives a nullable value, while the viewModel returns a non-null value. Change the text parameter to be non-null, just like the function in the viewModel returns it.

You can also do shorter encapsulation, for example:

private val _data = MutableLiveData<String>()
val data: LiveData<String>
  get() = _data

This way you don't have to write long and boring getters like in Java.

Answer 2

As per your GameViewModel , I don't think you need any custom binding adapter.

Please check the edited code.

GameViewModel

class GameViewModel:BaseViewModel() {
    // Make the variables public and access directly instead of exposing them via get() method.
    val awayTeamName = MutableLiveData<String>()
    val homeTeamName = MutableLiveData<String>()
    val awayTeamScore = MutableLiveData<String>() // Change to String
    val homeTeamScore = MutableLiveData<String>() // Change to String
    val timeRemaining = MutableLiveData<String>()

    fun bind(response: Game) {
        awayTeamName.value = response.gameData.teams.get(0).name
        homeTeamName.value = response.gameData.teams.get(1).name
        awayTeamScore.value = response.liveData.linescore.teams.get(1).goals.toString() // Convert to String from here only instead of writing it in XML!
        homeTeamScore.value = response.liveData.linescore.teams.get(0).goals.toString()
        timeRemaining.value = response.liveData.linescore.currentPeriodOrdinal + " " + response.liveData.linescore.currentPeriodTimeRemaining
    }
}

Your layout file (Notice I accessed the variables directly and removed the toString() as we are now only exposing MutableLiveData with String and yes, we are not using your custom binding adapter.

<data>
    <variable
        name="viewModel"
        type="com.example.nhlstats.ui.game.GameViewModel" />
</data>
<LinearLayout
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <LinearLayout
        android:id="@+id/awayTeam"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_marginTop="12dp">

        <ImageView
            android:id="@+id/awayTeamLogo"
            android:layout_height="48dp"
            android:layout_width="0dp"
            android:layout_weight="1"
            tools:src="@drawable/ic_launcher_background"/>

        <TextView
            android:id="@+id/awayTeamName"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="3"
            android:layout_gravity="center_vertical"
            android:text="@{viewModel.awayTeamName}"
            tools:text="CHI Blackhawks"/>

        <TextView
            android:id="@+id/awayScore"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_gravity="center_vertical"
            android:text="@{viewModel.awayTeamScore}"
            tools:text="0"/>
        <TextView

            android:id="@+id/gameTime"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_gravity="center_vertical"
            android:text="@{viewModel.timeRemaining}"
            tools:text="14:26 3rd"/>

    </LinearLayout>

    <LinearLayout
        android:id="@+id/homeTeam"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="12dp">

        <ImageView
            android:id="@+id/homeTeamLogo"
            android:layout_height="48dp"
            android:layout_width="0dp"
            android:layout_weight="1"
            tools:src="@drawable/ic_launcher_background"/>

        <TextView
            android:id="@+id/homeTeamName"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="3"
            android:layout_gravity="center_vertical"
            android:text="@{viewModel.homeTeamName}"
            tools:text="CAR Hurricanes"/>

        <TextView
            android:id="@+id/homeScore"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:layout_weight="2"
            android:text="@{viewModel.homeTeamScore}"
            tools:text="4"/>
    </LinearLayout>
</LinearLayout>

I haven't tested this so let me know how this goes for you.