GridView elements horizontal spacing not working at all - android-layout

Question

So here's how my grid view looks like:
a http://imageshack.com/a/img41/7857/roir.png
I use some online JSON parsing and get the image thumbnail links and then pass it on as an array to the custom adapter and it sets images for which I again use some 3rd party library etc. But the 3rd party library is just used to set the image to the imageview. That's it.
So I have a main FragmentActivity. It has 2 fragments inside of it. The textbox u see there is inside one fragment(search fragment) and on top of it, the gridview is held by the second fragment. (results fragment)
Code for the results fragment:
<RelativeLayout 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:background="#f0f0f0"
tools:context="com.example.wikipicsearch.MainActivity" >
<GridView
android:id="#+id/gridView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:columnWidth="100dp"
android:gravity="center"
android:numColumns="auto_fit"
android:verticalSpacing="5dp"
android:drawSelectorOnTop="true"
android:stretchMode="columnWidth" >
</GridView>
</RelativeLayout>
Code for the layout that I pass onto the custom Adapter:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="5dp"
android:clickable="true"
android:background="#drawable/grid_color_selector"
android:focusable="true">
<ImageView
android:id="#+id/image"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_margin="0dp"
android:layout_gravity="center" >
</ImageView>
</LinearLayout>
Now, I have no clue why on earth is there no horizontal spacing between each of that linear layout. I tried using android:layout_marginLeft etc etc... nothing works at all! I made the fragment holding the gridview look grey so that the each element in the grid will leave some spacing and it should look good. Please help me out with this. TIA!

Answer 1

Android:horizontalSpacing="20dp" this doesn't work, if you have a fixed size in the root element (ex- card) of the item layout that you are setting for the grid
Set the width like this - android:layout_width="match_parent"
Activiy layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
tools:context=".views.legacy_grid_view.LegacyGridActivity">
<GridView
android:layout_height="match_parent"
android:id="#+id/legacyGrid"
android:background="#color/teal_700"
android:layout_width="match_parent"
android:numColumns="2"
android:horizontalSpacing="20dp"
android:verticalSpacing="20dp"/>
</LinearLayout>
Item layout
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView 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:layout_width="match_parent"
android:layout_height="200dp"
app:cardCornerRadius="10dp"
app:cardElevation="5dp">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="#+id/imageView2"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="32dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="32dp"
android:layout_marginBottom="60dp"
android:scaleType="fitCenter"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#android:drawable/presence_away" />
<TextView
android:id="#+id/legacyGridEmail"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_marginTop="16dp"
android:layout_marginBottom="16dp"
android:text="Email"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageView2" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
Result