ScrollView无法正常工作

Question

I have two XML layout files, each has a ScrollView as parent. While one is working properly, the other one doesn't (each XML has the same hierarchy).

activity_login.xml

<?xml version="1.0" encoding="utf-8"?>
<ScrollView 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"
android:fillViewport="true">

<android.support.constraint.ConstraintLayout
    android:id="@+id/login_container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/tvLogo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/logo"
        android:textSize="50sp"
        app:layout_constraintBottom_toTopOf="@+id/guideline2"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.25" />

    <TextView
        android:id="@+id/tvRegisterLabel"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="3dp"
        android:layout_marginStart="3dp"
        android:text="@string/btn_login"
        android:textSize="20sp"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="@+id/guideline3"
        app:layout_constraintRight_toLeftOf="@+id/guideline6"
        app:layout_constraintTop_toTopOf="@+id/guideline2" />

    <android.support.design.widget.TextInputLayout
        android:id="@+id/textInputLayout2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        app:layout_constraintLeft_toLeftOf="@+id/guideline3"
        app:layout_constraintRight_toLeftOf="@+id/guideline6"
        app:layout_constraintTop_toBottomOf="@+id/tvRegisterLabel">

        <EditText
            android:id="@+id/etEmail"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/et_email_hint"
            android:inputType="textEmailAddress"
            android:maxLength="70"
            android:maxLines="1"
            android:minLines="1"
            android:text="akarki@yahoo.com"
            android:textSize="@dimen/et_hint_size" />
    </android.support.design.widget.TextInputLayout>

    <android.support.constraint.Guideline
        android:id="@+id/guideline3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.15" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.85" />

    <android.support.design.widget.TextInputLayout
        android:id="@+id/textInputLayout7"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="@+id/guideline3"
        app:layout_constraintRight_toLeftOf="@+id/guideline6"
        app:layout_constraintTop_toBottomOf="@+id/textInputLayout2">

        <EditText
            android:id="@+id/etPassword"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/et_password_hint"
            android:inputType="textPassword"
            android:maxLength="30"
            android:maxLines="1"
            android:minLines="1"
            android:text="1234qwer"
            android:textSize="@dimen/et_hint_size" />
    </android.support.design.widget.TextInputLayout>

    <ProgressBar
        android:id="@+id/progressBar"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginTop="8dp"
        android:visibility="invisible"
        app:layout_constraintLeft_toLeftOf="@+id/guideline3"
        app:layout_constraintRight_toLeftOf="@+id/guideline6"
        app:layout_constraintTop_toBottomOf="@+id/textInputLayout7" />

    <Button
        android:id="@+id/btnLogIn"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:background="@drawable/round_button"
        android:text="@string/btn_login"
        android:textColor="@color/colorWhite"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="@+id/guideline3"
        app:layout_constraintRight_toLeftOf="@+id/guideline6"
        app:layout_constraintTop_toBottomOf="@+id/progressBar" />

    <com.facebook.login.widget.LoginButton
        android:id="@+id/btnFacebook"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:paddingBottom="15dp"
        android:paddingLeft="15dp"
        android:paddingTop="15dp"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="@+id/guideline3"
        app:layout_constraintRight_toLeftOf="@+id/guideline6"
        app:layout_constraintTop_toBottomOf="@+id/btnLogIn" />

    <ImageButton
        android:id="@+id/btnGoogle"
        android:layout_width="0dp"
        android:layout_height="50dp"
        android:layout_marginTop="8dp"
        android:background="@drawable/google_round_button"
        android:scaleType="centerInside"
        android:src="@drawable/google_button_background"
        app:layout_constraintLeft_toLeftOf="@+id/guideline3"
        app:layout_constraintRight_toLeftOf="@+id/guideline6"
        app:layout_constraintTop_toBottomOf="@+id/btnFacebook" />

    <TextView
        android:id="@+id/tvRegister"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginTop="8dp"
        android:maxLines="2"
        android:text="@string/tv_create_account"
        android:textAlignment="center"
        android:textColor="@color/colorPrimaryDark"
        android:textSize="14sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="@+id/guideline3"
        app:layout_constraintRight_toLeftOf="@+id/guideline6"
        app:layout_constraintTop_toBottomOf="@+id/tvForgotPassword" />

    <TextView
        android:id="@+id/tvForgotPassword"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="@string/tv_forgot_password"
        android:textAlignment="center"
        android:textColor="@color/colorAccent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="@+id/guideline3"
        app:layout_constraintRight_toLeftOf="@+id/guideline6"
        app:layout_constraintTop_toBottomOf="@+id/btnGoogle" />
</android.support.constraint.ConstraintLayout>

activity_register

<?xml version="1.0" encoding="utf-8"?>
<ScrollView
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"
android:fillViewport="true">

<android.support.constraint.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="10dp">

    <android.support.constraint.Guideline
        android:id="@+id/guideline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.25" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.15" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.85" />

    <TextView
        android:id="@+id/tvLogo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/logo"
        android:textSize="50sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toTopOf="@+id/guideline"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/tvRegisterLabel"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="3dp"
        android:layout_marginLeft="3dp"
        android:layout_marginRight="3dp"
        android:layout_marginStart="3dp"
        android:fontFamily="sans-serif"
        android:text="@string/label_register"
        android:textAllCaps="true"
        android:textSize="20sp"
        app:layout_constraintLeft_toLeftOf="@+id/guideline4"
        app:layout_constraintRight_toRightOf="@+id/guideline5"
        app:layout_constraintTop_toTopOf="@+id/guideline" />

    <android.support.design.widget.TextInputLayout
        android:id="@+id/textInputLayout"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="@+id/guideline4"
        app:layout_constraintRight_toRightOf="@+id/guideline5"
        app:layout_constraintTop_toBottomOf="@+id/tvRegisterLabel">

        <EditText
            android:id="@+id/etEmailReg"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:focusable="true"
            android:hint="@string/et_email_hint"
            android:inputType="textEmailAddress"
            android:maxLength="70"
            android:maxLines="1"
            android:minLines="1"
            android:textSize="@dimen/et_hint_size" />
    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/textInputLayout3"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="@+id/guideline4"
        app:layout_constraintRight_toRightOf="@+id/guideline5"
        app:layout_constraintTop_toBottomOf="@+id/textInputLayout">

        <EditText
            android:id="@+id/etNameReg"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:focusable="true"
            android:hint="@string/et_name_hint"
            android:inputType="textCapWords"
            android:maxLength="30"
            android:maxLines="1"
            android:minLines="1"
            android:textSize="@dimen/et_hint_size" />
    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/textInputLayout4"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="@+id/guideline4"
        app:layout_constraintRight_toRightOf="@+id/guideline5"
        app:layout_constraintTop_toBottomOf="@+id/textInputLayout3">

        <EditText
            android:id="@+id/etPasswordReg"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:focusable="true"
            android:hint="@string/et_password_hint"
            android:inputType="textPassword"
            android:maxLength="30"
            android:maxLines="1"
            android:minLines="1"
            android:textSize="@dimen/et_hint_size" />
    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/textInputLayout5"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="@+id/guideline4"
        app:layout_constraintRight_toRightOf="@+id/guideline5"
        app:layout_constraintTop_toBottomOf="@+id/textInputLayout4">

        <EditText
            android:id="@+id/etPasswordConfirmReg"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:focusable="true"
            android:hint="@string/et_password_confirm_hint"
            android:inputType="textPassword"
            android:maxLength="30"
            android:maxLines="1"
            android:minLines="1"
            android:textSize="@dimen/et_hint_size" />
    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/textInputLayout6"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="@+id/guideline4"
        app:layout_constraintRight_toRightOf="@+id/guideline5"
        app:layout_constraintTop_toBottomOf="@+id/textInputLayout5">

        <EditText
            android:id="@+id/etPhoneNumber"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:focusable="true"
            android:hint="@string/et_phone_hint"
            android:inputType="phone"
            android:maxLength="13"
            android:maxLines="1"
            android:minLines="1"
            android:textSize="@dimen/et_hint_size" />
    </android.support.design.widget.TextInputLayout>

    <TextView
        android:id="@+id/tvRequired"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="@string/label_required"
        android:textAlignment="textStart"
        android:textSize="12sp"
        app:layout_constraintLeft_toLeftOf="@+id/guideline4"
        app:layout_constraintRight_toRightOf="@+id/guideline5"
        app:layout_constraintTop_toBottomOf="@+id/textInputLayout6" />

    <Button
        android:id="@+id/btnRegister"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="40dp"
        android:background="@drawable/round_button"
        android:text="@string/label_register"
        android:textColor="@android:color/white"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="@+id/guideline4"
        app:layout_constraintRight_toRightOf="@+id/guideline5"
        app:layout_constraintTop_toBottomOf="@+id/tvRequired" />
</android.support.constraint.ConstraintLayout>

So, to clarify my problem: In the activity_login the scrollview works correctly, as expected. While in the activity_register the scrollview doesn't scroll to the bottom, I don't know why, because I've used the same hierarcy as in the activity_login .

I've searched in SO for the same problem, but I haven't found any solution to my problem.
Any help would be appreciated, I'm searching for a solution for days.

Answer 1

I don't know for sure why it's a problem, but the problem seems to be your horizontal Guideline . If I delete the Guideline , delete tvLogo 's reference to it, and change tvRegisterLabel 's reference to app:layout_constraintTop_toBottomOf="@+id/tvLogo" , everything works.

I suspect that it is because you seem to have a circular set of rules in your layout. The ConstraintLayout 's height is wrap_content , so it has to lay out all of its views to know how big it is. To lay out its views, it must lay out tvLogo . To lay out tvLogo , it must lay out guideline . To lay out guideline , the ConstraintLayout must know how tall it is. And so on.

By the way, it looks like you could perhaps just replace this ConstraintLayout with a LinearLayout .

Answer 2

Sorry couldn't have much reputations to add comment so giving answer,

<android.support.constraint.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="10dp">

remove padding from this code in activity_register xml, It will solve your problem