第二次导航后，对讲系统不聚焦新片段

Question

我有一个用Android导航的app(单个活动很多片段)。< br >启动时，该应用程序会显示一个加载屏幕，这是一个可选的“新闻”类型的屏幕，当用户完成后会返回到主屏幕，然后是主屏幕。< br >但是，我无法访问主屏幕。当新闻屏幕不显示时，它会很好地聚焦，但当它被包括在内时，主屏幕将不会获得焦点，它似乎仍然在加载屏幕上。

我已经能够在一个最小的例子中重现这一点，用屏幕“加载”、“A”和“B”。这里的应用行为是:

• 在主片段上启动
• 等待5秒，导航到片段A
• 用户按“继续”
• 返回主片段
• 等待5秒，导航到片段B

每次导航后，我都希望文本元素被聚焦并读出。然而，对于片段B，它不是。

我尝试过的事情：

< li >使用<代码>

如果我将加载片段更改为使用按钮进行导航，而不是自动行为，则焦点确实会正确传递，但显然不会提供正确的体验。

class LoadingFragment : Fragment() {

    private lateinit var rootView: View

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View = inflater.inflate(R.layout.fragment_main, container, false).also {
        rootView = it
    }

    private var beenHereBefore = false

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        // Mimic a delayed loading process
        Handler(Looper.getMainLooper()).postDelayed({
            // Navigate to the correct screen, based on state
            findNavController().navigate(
                if (beenHereBefore) {
                    R.id.action_mainFragment_to_fragmentB
                } else {
                    beenHereBefore = true
                    R.id.action_mainFragment_to_fragmentA
                }
            )
        }, 5000)
    }
}

fragment_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.main.LoadingFragment">

    <TextView
        android:id="@+id/message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="MainFragment"
        android:textColor="@color/black"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

class FragmentA : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View = inflater.inflate(R.layout.fragment_a, container, false)

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        view.findViewById<Button>(R.id.button).setOnClickListener {
            findNavController().popBackStack()
        }
    }
}

fragment_a.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Fragment A"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="308dp"
        android:text="Continue"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />
</androidx.constraintlayout.widget.ConstraintLayout>

class FragmentB : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View = inflater.inflate(R.layout.fragment_b, container, false)
}

fragment_b.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Fragment B"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

main_graph.xml

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_graph"
    app:startDestination="@id/mainFragment">

    <fragment
        android:id="@+id/mainFragment"
        android:name="com.example.navigationtestapp.ui.main.LoadingFragment"
        android:label="fragment_main"
        tools:layout="@layout/fragment_main" >
        <action
            android:id="@+id/action_mainFragment_to_fragmentA"
            app:destination="@id/fragmentA" />
        <action
            android:id="@+id/action_mainFragment_to_fragmentB"
            app:destination="@id/fragmentB" />
    </fragment>
    <fragment
        android:id="@+id/fragmentA"
        android:name="com.example.navigationtestapp.ui.main.FragmentA"
        android:label="FragmentA" />
    <fragment
        android:id="@+id/fragmentB"
        android:name="com.example.navigationtestapp.ui.main.FragmentB"
        android:label="FragmentB" />
</navigation>

Answer 1

如果我是，您将尝试使用可访问性API而不是请求焦点来处理可访问性焦点。您已经提到焦点似乎由加载屏幕保持，因此这应该可以工作，因为a11y焦点将跟随它，但我会尝试使用sendAccessibilityEvent方法https://developer.android.com/reference/android/view/accessibility/AccessibilityEventSource#sendAccessibilityEvent（int）来处理它

// Moving a11y focus from btn1 to btn 2

        btn1 = (Button) findViewById(R.id.screen3_btn1);
        btn2 = (Button) findViewById(R.id.screen3_btn2);

        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                btn2.sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);
            }
        });

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