Android Kotlin 将片段充气到容器中失败

Question

我在我的 Android 项目中使用 Kotlin，当将 fragments 添加到容器时，我收到一条错误消息，提示 特定 ID 的视图不是可用 和应用程序崩溃。这是从添加第二个片段开始发生的。

首先我认为这可能是约束布局的问题，并将活动布局实现更改为相对布局实现，并意识到它在这种情况下并没有造成问题。这是某种奇怪的行为，因为我在 Java 中做了同样的事情它工作正常，在我的实现中没有找到任何解决方案或可见问题。

我的activity布局是这样实现的

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentStart="true" />
</RelativeLayout>

我的 Fragment 交易是这样完成的

supportFragmentManager
                .beginTransaction()
                .add(R.id.content_frame, CreateAccountFragment.newInstance())
                .addToBackStack(CreateAccountFragment.javaClass.simpleName)
                .commit()

我的片段实现如下

片段布局

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

    <data>
        <variable
            name="viewModel"
            type="test.feature.createAccount.CreateAccountViewModel"/>
    </data>

    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <!-- AppBar and Toolbar -->
        <include
            android:id="@+id/include"
            layout="@layout/appbar_layout"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <ImageView
            android:id="@+id/imageView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="@dimen/padding_m"
            android:layout_marginEnd="@dimen/padding_m"
            android:layout_marginStart="@dimen/padding_m"
            android:layout_marginTop="@dimen/padding_xxl"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/include"
            app:layout_constraintVertical_bias="0.0"
            app:srcCompat="@drawable/test_logo_large" />

        <!-- Content -->

        <test.feature.shared.EditTextWithIcon
            android:id="@+id/nameEditTextWithLabel"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginEnd="40dp"
            android:layout_marginStart="40dp"
            android:layout_marginTop="32dp"
            android:imeOptions="actionNext"
            android:nextFocusDown="@+id/passwordEditTextWithLabel"
            app:edit_text_email="true"
            app:edit_text_hint="@string/name_hint"
            app:edit_text_icon="@drawable/ic_name_24dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/imageView"
            app:text="@{viewModel.email}" />

        <test.feature.shared.EditTextWithIcon
            android:id="@+id/emailEditTextWithLabel"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginEnd="40dp"
            android:layout_marginStart="40dp"
            android:imeOptions="actionNext"
            android:nextFocusDown="@+id/passwordEditTextWithLabel"
            app:edit_text_email="true"
            app:edit_text_hint="@string/email_hint"
            app:edit_text_icon="@drawable/ic_email_24dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/nameEditTextWithLabel"
            app:text="@{viewModel.email}" />

        <test.feature.shared.EditTextWithIcon
            android:id="@+id/passwordEditTextWithLabel"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginEnd="40dp"
            android:layout_marginStart="40dp"
            android:imeOptions="actionDone"
            app:edit_text_hint="@string/password_hint"
            app:edit_text_icon="@drawable/ic_password_24dp"
            app:edit_text_password="true"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/emailEditTextWithLabel"
            app:text="@{viewModel.password}" />

        <test.feature.shared.CheckBoxWithHint
            android:id="@+id/acceptTermsCheckBox"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginEnd="40dp"
            android:layout_marginStart="40dp"
            app:checkbox_text="@string/accept_saving_data_checkbox_text"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/passwordEditTextWithLabel" />

        <Button
            android:id="@+id/goToSignUpButton"
            style="@style/SecondaryButton"
            android:text="@string/sign_up_button"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/acceptTermsCheckBox" />

    </android.support.constraint.ConstraintLayout>

</layout>

片段类

class CreateAccountFragment : Fragment() {

    companion object {
        fun newInstance(): CreateAccountFragment {
            return CreateAccountFragment()
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        retainInstance = true
    }

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

    private val viewModel: CreateAccountViewModel by lazy {
        ViewModelProviders.of(this).get(CreateAccountViewModel::class.java)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //setup ui
        setTitle(R.string.create_account_title)
        setSupportActionBar(toolbar)

        val binding = activity?.let { DataBindingUtil.setContentView<FragmentCreateAccountBinding>(it, R.layout.fragment_create_account) }
        binding?.viewModel = viewModel
        binding?.setLifecycleOwner(activity)
        binding?.executePendingBindings()

        nameEditTextWithLabel.toObservableValue().subscribe {
            viewModel.setName(it)
        }

        emailEditTextWithLabel.toObservableValue().subscribe {
            viewModel.setEmail(it)
        }

        passwordEditTextWithLabel.toObservableValue().subscribe {
            viewModel.setPassword(it)
        }
    }
}

应用崩溃时的日志如下所示

08-22 14:48:25.393 6905-6905/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: ec.test.android.debug, PID: 6905
    java.lang.IllegalArgumentException: No view found for id 0x7f09003c (ec.test.android.debug:id/content_frame) for fragment CreateAccountFragment{82d27b9 #1 id=0x7f09003c}
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1422)
        at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1759)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1827)
        at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:797)
        at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2596)
        at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2383)
        at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2338)
        at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2245)
        at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:703)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

我无法确定崩溃的原因，它很好地添加了第一个片段，然后从下一个片段开始出现此错误并崩溃。

Answer 1

尝试使用替换方法而不是添加方法。

supportFragmentManager
            .beginTransaction()
            .replace(R.id.content_frame, CreateAccountFragment.newInstance())
            .addToBackStack(CreateAccountFragment.javaClass.simpleName)
            .commit()