android - ConstraintLayout不包装内容

我在CardView里面有一个约束布局。
按钮按如图所示的网格格式排列。但由于某些原因，空白显示在按钮下面。我想去掉这个空白。

这是XML代码

             <android.support.v7.widget.CardView
        android:id="@+id/cvSpecialisations"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        app:cardElevation="2dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/bViewAll">

        <android.support.constraint.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">


            <TextView
                android:id="@+id/tvSearchBySpecialisation"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="8dp"
                android:layout_marginLeft="8dp"
                android:layout_marginRight="8dp"
                android:layout_marginStart="8dp"
                android:layout_marginTop="8dp"
                android:text="Search by specialisation"
                android:textSize="14dp"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintRight_toRightOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <View
                android:id="@+id/vDividerInSpecialisationCard"
                style="@style/Divider"
                android:layout_width="0dp"
                android:layout_height="1dp"
                android:layout_marginBottom="8dp"
                android:layout_marginEnd="8dp"
                android:layout_marginLeft="8dp"
                android:layout_marginRight="8dp"
                android:layout_marginStart="8dp"
                android:layout_marginTop="8dp"
                app:layout_constraintBottom_toTopOf="parent"
                app:layout_constraintHorizontal_bias="1.0"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintRight_toRightOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/tvSearchBySpecialisation"
                app:layout_constraintVertical_bias="0.0" />

            <Button
                android:id="@+id/bSpecialisation1"
                style="@style/Widget.AppCompat.Button.Borderless"
                android:layout_width="88dp"
                android:layout_height="92dp"
                android:layout_marginLeft="32dp"
                android:layout_marginStart="32dp"
                android:drawablePadding="8dp"
                android:drawableTop="@mipmap/ic_launcher"
                android:fontFamily="san-serif"
                android:paddingLeft="-5dp"
                android:paddingRight="-5dp"
                android:text="Car"
                android:textAllCaps="false"
                android:theme="@style/AppTheme.WhiteButton"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintTop_toTopOf="@+id/bSpecialisation2" />

            <Button
                android:id="@+id/bSpecialisation2"
                style="@style/Widget.AppCompat.Button.Borderless"
                android:layout_width="88dp"
                android:layout_height="92dp"
                android:layout_marginEnd="8dp"
                android:layout_marginLeft="8dp"
                android:layout_marginRight="8dp"
                android:layout_marginStart="8dp"
                android:layout_marginTop="16dp"
                android:drawablePadding="8dp"
                android:drawableTop="@mipmap/ic_launcher"
                android:fontFamily="san-serif"
                android:paddingLeft="-5dp"
                android:paddingRight="-5dp"
                android:text="Car"
                android:textAllCaps="false"
                android:theme="@style/AppTheme.WhiteButton"
                app:layout_constraintLeft_toRightOf="@+id/bSpecialisation1"
                app:layout_constraintRight_toLeftOf="@+id/bSpecialisation3"
                app:layout_constraintTop_toBottomOf="@+id/vDividerInSpecialisationCard" />

            <Button
                android:id="@+id/bSpecialisation3"
                style="@style/Widget.AppCompat.Button.Borderless"
                android:layout_width="88dp"
                android:layout_height="92dp"
                android:layout_marginEnd="32dp"
                android:layout_marginRight="32dp"
                android:drawablePadding="8dp"
                android:drawableTop="@mipmap/ic_launcher"
                android:fontFamily="san-serif"
                android:paddingLeft="-5dp"
                android:paddingRight="-5dp"
                android:text="Car"
                android:textAllCaps="false"
                android:theme="@style/AppTheme.WhiteButton"
                app:layout_constraintRight_toRightOf="parent"
                app:layout_constraintTop_toTopOf="@+id/bSpecialisation2" />

            <Button
                android:id="@+id/bSpecialisation4"
                style="@style/Widget.AppCompat.Button.Borderless"
                android:layout_width="88dp"
                android:layout_height="92dp"
                android:layout_marginEnd="32dp"
                android:layout_marginRight="32dp"
                android:drawablePadding="8dp"
                android:drawableTop="@mipmap/ic_launcher"
                android:fontFamily="san-serif"
                android:paddingLeft="-5dp"
                android:paddingRight="-5dp"
                android:text="Car"
                android:textAllCaps="false"
                android:theme="@style/AppTheme.WhiteButton"
                app:layout_constraintRight_toRightOf="parent"
                app:layout_constraintTop_toTopOf="@+id/bSpecialisation5" />

            <Button
                android:id="@+id/bSpecialisation5"
                style="@style/Widget.AppCompat.Button.Borderless"
                android:layout_width="88dp"
                android:layout_height="92dp"
                android:layout_marginEnd="8dp"
                android:layout_marginLeft="8dp"
                android:layout_marginRight="8dp"
                android:layout_marginStart="8dp"
                android:layout_marginTop="14dp"
                android:drawablePadding="8dp"
                android:drawableTop="@mipmap/ic_launcher"
                android:fontFamily="san-serif"
                android:paddingLeft="-5dp"
                android:paddingRight="-5dp"
                android:text="Car"
                android:textAllCaps="false"
                android:theme="@style/AppTheme.WhiteButton"
                app:layout_constraintLeft_toRightOf="@+id/bSpecialisation6"
                app:layout_constraintRight_toLeftOf="@+id/bSpecialisation4"
                app:layout_constraintTop_toBottomOf="@+id/bSpecialisation2" />

            <Button
                android:id="@+id/bSpecialisation6"
                style="@style/Widget.AppCompat.Button.Borderless"
                android:layout_width="88dp"
                android:layout_height="92dp"
                android:layout_marginLeft="32dp"
                android:layout_marginStart="32dp"
                android:drawablePadding="8dp"
                android:drawableTop="@mipmap/ic_launcher"
                android:fontFamily="san-serif"
                android:paddingLeft="-5dp"
                android:paddingRight="-5dp"
                android:text="Car"
                android:textAllCaps="false"
                android:theme="@style/AppTheme.WhiteButton"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintTop_toTopOf="@+id/bSpecialisation5" />


        </android.support.constraint.ConstraintLayout>

    </android.support.v7.widget.CardView>

我已尝试更改宽度和高度以匹配父包装内容

最佳答案

您的CardView不包装内容，因为所有垂直元素都应放置“打包”链。
所以我添加了app:layout_constraintVertical_chainStyle="packed"和一些额外的垂直边距：

<android.support.v7.widget.CardView
    android:id="@+id/cvSpecialisations"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginTop="8dp"
    app:cardElevation="2dp"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/bViewAll" >

    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:id="@+id/tvSearchBySpecialisation"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginRight="8dp"
            android:text="Search by specialisation"
            android:textSize="14dp"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintBottom_toTopOf="@+id/vDividerInSpecialisationCard"
            app:layout_constraintVertical_chainStyle="packed"/>

        <View
            android:id="@+id/vDividerInSpecialisationCard"
            style="@style/Divider"
            android:layout_width="0dp"
            android:layout_height="1dp"
            android:layout_marginTop="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginRight="8dp"
            android:layout_marginBottom="8dp"
            app:layout_constraintTop_toBottomOf="@+id/tvSearchBySpecialisation"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintBottom_toTopOf="@+id/bSpecialisation2"/>

        <Button
            android:id="@+id/bSpecialisation1"
            style="@style/Widget.AppCompat.Button.Borderless"
            android:layout_width="88dp"
            android:layout_height="92dp"
            android:layout_marginLeft="32dp"
            android:drawablePadding="8dp"
            android:drawableTop="@mipmap/ic_launcher"
            android:fontFamily="san-serif"
            android:paddingLeft="-5dp"
            android:paddingRight="-5dp"
            android:text="Car"
            android:textAllCaps="false"
            android:theme="@style/AppTheme.WhiteButton"
            app:layout_constraintTop_toTopOf="@+id/bSpecialisation2"
            app:layout_constraintLeft_toLeftOf="parent" />

        <Button
            android:id="@+id/bSpecialisation2"
            style="@style/Widget.AppCompat.Button.Borderless"
            android:layout_width="88dp"
            android:layout_height="92dp"
            android:layout_marginTop="16dp"
            android:layout_marginLeft="8dp"
            android:layout_marginRight="8dp"
            android:drawablePadding="8dp"
            android:drawableTop="@mipmap/ic_launcher"
            android:fontFamily="san-serif"
            android:paddingLeft="-5dp"
            android:paddingRight="-5dp"
            android:text="Car"
            android:textAllCaps="false"
            android:theme="@style/AppTheme.WhiteButton"
            app:layout_constraintTop_toBottomOf="@+id/vDividerInSpecialisationCard"
            app:layout_constraintLeft_toRightOf="@+id/bSpecialisation1"
            app:layout_constraintRight_toLeftOf="@+id/bSpecialisation3"
            app:layout_constraintBottom_toTopOf="@+id/bSpecialisation5" />

        <Button
            android:id="@+id/bSpecialisation3"
            style="@style/Widget.AppCompat.Button.Borderless"
            android:layout_width="88dp"
            android:layout_height="92dp"
            android:layout_marginRight="32dp"
            android:drawablePadding="8dp"
            android:drawableTop="@mipmap/ic_launcher"
            android:fontFamily="san-serif"
            android:paddingLeft="-5dp"
            android:paddingRight="-5dp"
            android:text="Car"
            android:textAllCaps="false"
            android:theme="@style/AppTheme.WhiteButton"
            app:layout_constraintTop_toTopOf="@+id/bSpecialisation2"
            app:layout_constraintRight_toRightOf="parent" />

        <Button
            android:id="@+id/bSpecialisation4"
            style="@style/Widget.AppCompat.Button.Borderless"
            android:layout_width="88dp"
            android:layout_height="92dp"
            android:layout_marginEnd="32dp"
            android:layout_marginRight="32dp"
            android:drawablePadding="8dp"
            android:drawableTop="@mipmap/ic_launcher"
            android:fontFamily="san-serif"
            android:paddingLeft="-5dp"
            android:paddingRight="-5dp"
            android:text="Car"
            android:textAllCaps="false"
            android:theme="@style/AppTheme.WhiteButton"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="@+id/bSpecialisation5" />

        <Button
            android:id="@+id/bSpecialisation5"
            style="@style/Widget.AppCompat.Button.Borderless"
            android:layout_width="88dp"
            android:layout_height="92dp"
            android:layout_marginTop="14dp"
            android:layout_marginLeft="8dp"
            android:layout_marginRight="8dp"
            android:drawablePadding="8dp"
            android:drawableTop="@mipmap/ic_launcher"
            android:fontFamily="san-serif"
            android:paddingLeft="-5dp"
            android:paddingRight="-5dp"
            android:text="Car"
            android:textAllCaps="false"
            android:theme="@style/AppTheme.WhiteButton"
            app:layout_constraintTop_toBottomOf="@+id/bSpecialisation2"
            app:layout_constraintLeft_toRightOf="@+id/bSpecialisation6"
            app:layout_constraintRight_toLeftOf="@+id/bSpecialisation4"
            app:layout_constraintBottom_toBottomOf="parent"/>

        <Button
            android:id="@+id/bSpecialisation6"
            style="@style/Widget.AppCompat.Button.Borderless"
            android:layout_width="88dp"
            android:layout_height="92dp"
            android:layout_marginLeft="32dp"
            android:drawablePadding="8dp"
            android:drawableTop="@mipmap/ic_launcher"
            android:fontFamily="san-serif"
            android:paddingLeft="-5dp"
            android:paddingRight="-5dp"
            android:text="Car"
            android:textAllCaps="false"
            android:theme="@style/AppTheme.WhiteButton"
            app:layout_constraintTop_toTopOf="@+id/bSpecialisation5"
            app:layout_constraintLeft_toLeftOf="parent" />

    </android.support.constraint.ConstraintLayout>

</android.support.v7.widget.CardView>

它应该看起来像：