Buttons won't fill the whole space

Question

I want my layout to display 6 buttons that fill the whole screen equally but at the moment each button fills just its padding.

Those 6 buttons are displayed inside a ConstraintLayout that is inside a ScrollView in order to display the layout well on any device.

This is my layout:

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport="true"
    tools:context=".MainActivity" >

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

        <Button
            android:id="@+id/idbutton1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="BUTTON1"
            app:layout_constraintBottom_toTopOf="@+id/idbutton3"
            app:layout_constraintEnd_toStartOf="@+id/idbutton2"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:background="#f0eb79"
            android:foreground="?attr/selectableItemBackground"
            android:drawableTop="@drawable/default_icon"
            android:textAllCaps="false"
            android:textColor="#ffffff"
            android:textSize="18sp"
            android:padding="25dp" />

        <Button
            android:id="@+id/idbutton2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="BUTTON2"
            app:layout_constraintBottom_toTopOf="@+id/idbutton4"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toEndOf="@+id/idbutton1"
            app:layout_constraintTop_toTopOf="parent"
            android:background="#000"
            android:foreground="?attr/selectableItemBackground"
            android:drawableTop="@drawable/default_icon"
            android:textAllCaps="false"
            android:textColor="#ffffff"
            android:textSize="18sp"
            android:padding="25dp" />

        <Button
            android:id="@+id/idbutton3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="BUTTON3"
            app:layout_constraintEnd_toStartOf="@+id/idbutton4"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/idbutton1"
            app:layout_constraintBottom_toTopOf="@+id/idbutton5"
            android:background="#f0eb79"
            android:foreground="?attr/selectableItemBackground"
            android:drawableTop="@drawable/default_icon"
            android:textAllCaps="false"
            android:textColor="#ffffff"
            android:textSize="18sp"
            android:padding="25dp" />

        <Button
            android:id="@+id/idbutton4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="BUTTON4"
            app:layout_constraintBottom_toTopOf="@+id/idAppointments"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toEndOf="@+id/idbutton3"
            app:layout_constraintTop_toBottomOf="@+id/idbutton2"
            android:background="#000"
            android:foreground="?attr/selectableItemBackground"
            android:drawableTop="@drawable/default_icon"
            android:textAllCaps="false"
            android:textColor="#ffffff"
            android:textSize="18sp"
            android:padding="25dp" />

        <Button
            android:id="@+id/idbutton5"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="BUTTON5"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toStartOf="@+id/idAppointments"
            app:layout_constraintTop_toBottomOf="@+id/idbutton3"
            app:layout_constraintStart_toStartOf="parent"
            android:background="#f0eb79"
            android:foreground="?attr/selectableItemBackground"
            android:drawableTop="@drawable/default_icon"
            android:textAllCaps="false"
            android:textColor="#ffffff"
            android:textSize="18sp"
            android:padding="25dp" />

        <Button
            android:id="@+id/idAppointments"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="BUTTON6"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toEndOf="@+id/idbutton5"
            app:layout_constraintTop_toBottomOf="@+id/idbutton4"
            android:background="#000"
            android:foreground="?attr/selectableItemBackground"
            android:drawableTop="@drawable/default_icon"
            android:textAllCaps="false"
            android:textColor="#ffffff"
            android:textSize="18sp"
            android:padding="25dp" />

    </android.support.constraint.ConstraintLayout>

</ScrollView>

This is the result I'm getting with the above code:
https://i.sstatic.net/euv7x.png

As you can see around the buttons there is the space that I don't want. Is there any way to make the buttons fill the whole space?

Answer 1

Try to use the code below (in this sample i removed android:drawableTop="@drawable/default_icon" but just add it again).

<?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"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/scrollView2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
tools:context=".MainActivity"
>

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

    <Button
        android:id="@+id/idbutton1"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#f0eb79"
        android:foreground="?attr/selectableItemBackground"
        android:padding="25dp"
        android:text="BUTTON1"
        android:textAllCaps="false"
        android:textColor="#ffffff"
        android:textSize="18sp"
        app:layout_constraintBottom_toTopOf="@+id/idbutton3"
        app:layout_constraintEnd_toStartOf="@+id/idbutton2"
        app:layout_constraintHorizontal_chainStyle="spread_inside"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/idbutton2"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#000"
        android:foreground="?attr/selectableItemBackground"
        android:padding="25dp"
        android:text="BUTTON2"
        android:textAllCaps="false"
        android:textColor="#ffffff"
        android:textSize="18sp"
        app:layout_constraintBottom_toTopOf="@+id/idbutton4"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/idbutton1"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/idbutton3"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#f0eb79"
        android:foreground="?attr/selectableItemBackground"
        android:padding="25dp"
        android:text="BUTTON3"
        android:textAllCaps="false"
        android:textColor="#ffffff"
        android:textSize="18sp"
        app:layout_constraintBottom_toTopOf="@+id/idbutton5"
        app:layout_constraintEnd_toStartOf="@+id/idbutton4"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/idbutton1" />

    <Button
        android:id="@+id/idbutton4"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#000"
        android:foreground="?attr/selectableItemBackground"
        android:padding="25dp"
        android:text="BUTTON4"
        android:textAllCaps="false"
        android:textColor="#ffffff"
        android:textSize="18sp"
        app:layout_constraintBottom_toTopOf="@+id/idAppointments"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/idbutton3"
        app:layout_constraintTop_toBottomOf="@+id/idbutton2" />

    <Button
        android:id="@+id/idbutton5"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#f0eb79"
        android:foreground="?attr/selectableItemBackground"
        android:padding="25dp"
        android:text="BUTTON5"
        android:textAllCaps="false"
        android:textColor="#ffffff"
        android:textSize="18sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/idAppointments"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/idbutton3" />

    <Button
        android:id="@+id/idAppointments"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#000"
        android:foreground="?attr/selectableItemBackground"
        android:padding="25dp"
        android:text="BUTTON6"
        android:textAllCaps="false"
        android:textColor="#ffffff"
        android:textSize="18sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/idbutton5"
        app:layout_constraintTop_toBottomOf="@+id/idbutton4" />

</android.support.constraint.ConstraintLayout>