Question

即使在布局XML代码中仅使用一个主布局，我仍然得到了“ ScrollView只能容纳一个直接子代”的信息。基本上，我想做的是从LoginFragment调用/启动RegisterFragment。我正在尝试使用以下代码来做到这一点：

     @Override
public void onClick(View view) {
    switch (view.getId()) {
        case R.id.vvLoginBanner: toggleVolume(); break;
        case R.id.btnLogin:      login(); break;
        case R.id.tvSignup:      FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            fragmentTransaction.replace(R.id.loginFragmentLayout, new RegisterFragment());
            fragmentTransaction.addToBackStack(null);
            fragmentTransaction.commit();
            break;
    }
}

以下是这两个XML文件的代码，它们可能会导致错误：

LoginFragment.xml

<ScrollView 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"
android:id="@+id/loginFragmentContainer"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:isScrollContainer="true"
tools:context="com.bvmobileapps.bvmobileapps.LoginFragment">

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <FrameLayout
        android:id="@+id/flBannerProgressBarWrapper"
        android:layout_alignParentTop="true"
        android:layout_width="match_parent"
        android:background="@color/black"
        android:layout_height="wrap_content">

        <ProgressBar
            android:id="@+id/pbBanner"
            android:layout_gravity="center"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:indeterminate="true"/>

    </FrameLayout>

<androidx.core.widget.NestedScrollView
    android:id="@+id/nsvScrollView"
    android:layout_below="@id/rlVideoWrapper"
    android:isScrollContainer="false"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <LinearLayout
        android:id="@+id/loginFragmentLayout"
        android:isScrollContainer="true"
        android:orientation="vertical"
        android:gravity="center"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <FrameLayout
            android:id="@+id/fragmentFrameLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>
        <LinearLayout
            android:id="@+id/llBannerWrapper"
            android:weightSum="100"
            android:orientation="horizontal"
            android:layout_marginTop="@dimen/inter_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <View
                android:layout_weight="10"
                android:layout_width="0dp"
                android:layout_height="1px"/>

            <ImageView
                android:id="@+id/ivBanner"
                android:src="@drawable/bv_banner"
                android:layout_weight="80"
                android:layout_width="0dp"
                android:layout_height="wrap_content" />

        </LinearLayout>

        <com.google.android.material.textfield.TextInputLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_marginBottom="@dimen/intra_item_margin"
            android:layout_marginTop="@dimen/inter_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/tvUsername"
                android:hint="@string/username_hint"
                android:singleLine="true"
                android:maxLength="20"
                android:imeOptions="actionNext"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </com.google.android.material.textfield.TextInputLayout>

        <com.google.android.material.textfield.TextInputLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/tvPassword"
                android:hint="@string/password_hint"
                android:fontFamily="@font/segoe_ui_light"
                android:maxLength="20"
                android:singleLine="true"
                android:imeOptions="actionDone"
                android:inputType="textPassword"
                android:gravity="start"
                android:ellipsize="start"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </com.google.android.material.textfield.TextInputLayout>

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal">


            <androidx.appcompat.widget.AppCompatButton
                android:id="@+id/btnLogin"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textColor="@color/white"
                android:layout_margin="@dimen/inter_item_margin"
                android:fontFamily="@font/segoe_ui_semi_bold"
                android:text="@string/login_btn"
                app:backgroundTint="@color/bv_blue" />

            <ProgressBar
                android:id="@+id/pbLogin"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:visibility="gone" />

        </RelativeLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="-14dp"
            android:layout_marginBottom="@dimen/inter_item_margin"
            android:gravity="center"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/tvSignup"
                android:text="@string/signup"
                android:textSize="@dimen/smallest_text"
                android:textColor="@color/bv_blue"
                android:textAlignment="center"
                android:layout_marginRight="20dp"
                android:layout_width="150dp"
                android:layout_height="wrap_content" />

            <TextView
                android:id="@+id/tvForgotPassword"
                android:text="@string/forgot_password"
                android:textSize="@dimen/smallest_text"
                android:textColor="@color/bv_blue"
                android:textAlignment="center"
                android:layout_marginLeft="0dp"
                android:layout_width="150dp"
                android:layout_height="wrap_content" />
        </LinearLayout>
    </LinearLayout>
</androidx.core.widget.NestedScrollView>
</RelativeLayout>

RegisterFragment.xml

<ScrollView 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"
android:id="@+id/registerFragmentContainer"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:isScrollContainer="true"
tools:context="com.bvmobileapps.bvmobileapps.RegisterFragment">

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <FrameLayout
        android:id="@+id/flBannerProgressBarWrapper"
        android:layout_alignParentTop="true"
        android:layout_width="match_parent"
        android:background="@color/black"
        android:layout_height="wrap_content">

        <ProgressBar
            android:id="@+id/pbBanner"
            android:layout_gravity="center"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:indeterminate="true"/>

    </FrameLayout>

<androidx.core.widget.NestedScrollView
    android:id="@+id/nsvScrollView"
    android:layout_below="@id/rlVideoWrapper"
    android:isScrollContainer="false"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <LinearLayout
        android:isScrollContainer="true"
        android:orientation="vertical"
        android:gravity="center"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

    <RelativeLayout
        android:id="@+id/registerFragmentLayout"
        android:layout_marginStart="@dimen/inter_item_margin"
        android:layout_marginEnd="@dimen/inter_item_margin"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="0dp"
        android:layout_marginBottom="0dp"
        android:gravity="center_horizontal"
        android:weightSum="10"
        android:orientation="horizontal">
        <ImageView
            android:id="@+id/ivValidUsername"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="21dp"
            android:layout_marginBottom="@dimen/intra_item_margin"
            android:scaleType="fitXY"
            android:src="@drawable/red_error" />
        <com.google.android.material.textfield.TextInputLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_marginBottom="@dimen/intra_item_margin"
            android:layout_marginTop="@dimen/inter_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/tvUsername"
                android:hint="@string/username_hint"
                android:singleLine="true"
                android:maxLength="20"
                android:layout_marginLeft="@dimen/inter_item_margin_left"
                android:imeOptions="actionNext"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        </com.google.android.material.textfield.TextInputLayout>
    </RelativeLayout>

        <include layout="@layout/horizontal_divider"
            android:id="@+id/source_divider"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="1dp"
            app:layout_constraintTop_toBottomOf="@id/photo_source_edit_text_wrapper"/>
    <RelativeLayout
        android:layout_marginStart="@dimen/inter_item_margin"
        android:layout_marginEnd="@dimen/inter_item_margin"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="0dp"
        android:layout_marginBottom="0dp"
        android:gravity="center_horizontal"
        android:weightSum="10"
        android:orientation="horizontal">
        <ImageView
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:id="@+id/ivValidEmail"
            android:layout_gravity="center_horizontal"
            android:src="@drawable/red_error"
            android:scaleType="fitXY"/>
        <com.google.android.material.textfield.TextInputLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/tvEmail"
                android:hint="@string/email_hint"
                android:fontFamily="@font/segoe_ui_light"
                android:maxLength="20"
                android:singleLine="true"
                android:imeOptions="actionDone"
                android:inputType="text"
                android:gravity="start"
                android:ellipsize="start"
                android:layout_marginLeft="@dimen/inter_item_margin_left"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </com.google.android.material.textfield.TextInputLayout>
    </RelativeLayout>

        <include layout="@layout/horizontal_divider"
            android:id="@+id/source_divider"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="1dp"
            app:layout_constraintTop_toBottomOf="@id/photo_source_edit_text_wrapper"/>

    <RelativeLayout
        android:layout_marginStart="@dimen/inter_item_margin"
        android:layout_marginEnd="@dimen/inter_item_margin"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="0dp"
        android:layout_marginBottom="0dp"
        android:gravity="center_horizontal"
        android:weightSum="10"
        android:orientation="horizontal">
        <ImageView
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:id="@+id/ivValidPassword"
            android:layout_gravity="center_horizontal"
            android:src="@drawable/red_error"
            android:scaleType="fitXY"/>
        <com.google.android.material.textfield.TextInputLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/tvPassword"
                android:hint="@string/password_hint"
                android:fontFamily="@font/segoe_ui_light"
                android:maxLength="20"
                android:singleLine="true"
                android:imeOptions="actionDone"
                android:inputType="textPassword"
                android:gravity="start"
                android:ellipsize="start"
                android:layout_marginLeft="@dimen/inter_item_margin_left"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </com.google.android.material.textfield.TextInputLayout>
    </RelativeLayout>
        <include layout="@layout/horizontal_divider"
            android:id="@+id/source_divider"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="1dp"
            app:layout_constraintTop_toBottomOf="@id/photo_source_edit_text_wrapper"/>

        <LinearLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="0dp"
            android:layout_marginBottom="0dp"
            android:gravity="center_horizontal"
            android:weightSum="10"
            android:orientation="horizontal">

            <com.google.android.material.textfield.TextInputLayout
                android:layout_marginTop="@dimen/intra_item_margin"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="5">

                <com.google.android.material.textfield.TextInputEditText
                    android:id="@+id/tvFirstName"
                    android:hint="@string/first_name_hint"
                    android:fontFamily="@font/segoe_ui_light"
                    android:maxLength="20"
                    android:singleLine="true"
                    android:imeOptions="actionDone"
                    android:inputType="text"
                    android:gravity="start"
                    android:ellipsize="start"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content" />

            </com.google.android.material.textfield.TextInputLayout>

            <com.google.android.material.textfield.TextInputLayout
                android:layout_marginTop="@dimen/intra_item_margin"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="5">

                <com.google.android.material.textfield.TextInputEditText
                    android:id="@+id/tvLastName"
                    android:hint="@string/last_name_hint"
                    android:fontFamily="@font/segoe_ui_light"
                    android:maxLength="20"
                    android:singleLine="true"
                    android:imeOptions="actionDone"
                    android:inputType="text"
                    android:gravity="start"
                    android:ellipsize="start"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content" />

            </com.google.android.material.textfield.TextInputLayout>

        </LinearLayout>

        <com.google.android.material.textfield.TextInputLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
            <Spinner
                android:id="@+id/spGender"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_margin="20dp"/>

        </com.google.android.material.textfield.TextInputLayout>
        <com.google.android.material.textfield.TextInputLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/tvZipCode"
                android:hint="@string/confirm_password_hint"
                android:fontFamily="@font/segoe_ui_light"
                android:maxLength="20"
                android:singleLine="true"
                android:imeOptions="actionDone"
                android:inputType="textPassword"
                android:gravity="start"
                android:ellipsize="start"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </com.google.android.material.textfield.TextInputLayout>
        <LinearLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="0dp"
            android:layout_marginBottom="0dp"
            android:gravity="center_horizontal"
            android:weightSum="25"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/tvBirthDate"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginStart="@dimen/inter_item_margin"
                android:layout_marginEnd="@dimen/inter_item_margin"
                android:layout_marginTop="@dimen/intra_item_margin"
                android:text="DateTime"/>

        </LinearLayout>

        <include layout="@layout/horizontal_divider"
            android:id="@+id/source_divider"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="1dp"
            app:layout_constraintTop_toBottomOf="@id/photo_source_edit_text_wrapper"/>

        <com.google.android.material.textfield.TextInputLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/tvSecurityQuestion"
                android:hint="@string/secret_question_hint"
                android:fontFamily="@font/segoe_ui_light"
                android:maxLength="20"
                android:singleLine="true"
                android:imeOptions="actionDone"
                android:inputType="textPassword"
                android:gravity="start"
                android:ellipsize="start"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </com.google.android.material.textfield.TextInputLayout>
        <com.google.android.material.textfield.TextInputLayout
            android:layout_marginStart="@dimen/inter_item_margin"
            android:layout_marginEnd="@dimen/inter_item_margin"
            android:layout_marginTop="@dimen/intra_item_margin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/tvSecurityQuestionAnswer"
                android:hint="@string/secret_question_answer_hint"
                android:fontFamily="@font/segoe_ui_light"
                android:maxLength="20"
                android:singleLine="true"
                android:imeOptions="actionDone"
                android:inputType="textPassword"
                android:gravity="start"
                android:ellipsize="start"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </com.google.android.material.textfield.TextInputLayout>
        <CheckBox
            android:id="@+id/agree"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="@dimen/appbar_padding_top"
            android:checked="true"
            android:text="@string/checkbox_label_termscond" />
        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal">

            <androidx.appcompat.widget.AppCompatButton
                android:id="@+id/btnRegister"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textColor="@color/white"
                android:layout_margin="@dimen/inter_item_margin"
                android:fontFamily="@font/segoe_ui_semi_bold"
                android:text="@string/submit_btn"
                app:backgroundTint="@color/bv_blue" />

            <ProgressBar
                android:id="@+id/pbRegister"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:visibility="gone" />
        </RelativeLayout>
    </LinearLayout>
</androidx.core.widget.NestedScrollView>
</RelativeLayout>

以下是在logcat中产生的以下错误消息：

java.lang.IllegalStateException: ScrollView can host only one direct child
    at android.widget.ScrollView.addView(ScrollView.java:273)
    at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1466)
    at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784)
    at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1852)
    at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:802)
    at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManager.java:2625)
    at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2411)
    at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2366)
    at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)
    at androidx.fragment.app.FragmentManagerImpl$1.run(FragmentManager.java:733)
    at android.os.Handler.handleCallback(Handler.java:790)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6651)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810)

现在，我确保在布局中只包含一个主布局，而其他嵌套布局包含在该主布局中。因此，基于此，我认为我应该不会收到该错误。任何帮助或建议解决此问题将不胜感激！

Answer 1

您的 xml 文件中缺少滚动视图的结束标记。顺便说一句，考虑使用嵌套滚动视图而不是滚动视图。（如文档中所述）

你也应该避免在另一个滚动视图中使用滚动视图。

建议：避免嵌套过多以提高布局性能。看看：Performance and view hierarchies

Answer 2

ScrollView 中必须只有一个子视图。您收到此错误是因为您没有使用完整的结束标记。

<ScrollView 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"
            android:id="@+id/loginFragmentContainer"
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:isScrollContainer="true"
            tools:context="com.bvmobileapps.bvmobileapps.LoginFragment">
        
    <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
    ....
    </RelativeLayout>
</ScrollView>

Android ScrollView错误-IllegalStateException：ScrollView只能托管一个直接子级

2 个答案: