Develop Reference

Transparent Background on Activity

I've been pulling my hair out with this specific issue. Whenever I load the current activity (on top) of the previous activity, it causes the background of the loading activity (with transparent background) to turn black.
I can see the transparent setting when the transition is loading, but when its fully loaded it turns black.
Here is the code I use to make the background transparent:
window.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))
The above code works elsewhere on another view just like this one. All settings are the same on both views, but this one doesn't want to work correctly.
This is the code for the activity:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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="match_parent"
android:background="#color/transparent"
android:fitsSystemWindows="true"
android:orientation="vertical"
android:scaleType="fitCenter"
tools:context=".ui.activities.TourConnectActivity">
<ImageView
android:id="#+id/backgroundImage"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginStart="24dp"
android:layout_marginTop="64dp"
android:layout_marginEnd="24dp"
android:background="#drawable/rounded_top"
android:contentDescription="background"
android:scaleType="centerCrop"
android:src="#drawable/launch_bg"
app:layout_constraintBottom_toTopOf="#+id/view7"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:ignore="HardcodedText" />
<View
android:id="#+id/view7"
android:layout_width="0dp"
android:layout_height="40dp"
android:layout_marginStart="24dp"
android:layout_marginEnd="24dp"
android:background="#drawable/preview_green_border_top"
app:layout_constraintBottom_toTopOf="#+id/linearLayout2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/backgroundImage" />
<ImageView
android:id="#+id/logo"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_marginStart="128dp"
android:layout_marginEnd="128dp"
android:background="#drawable/org_logo_border"
android:contentDescription="background"
android:cropToPadding="true"
android:scaleType="fitCenter"
app:layout_constraintBottom_toBottomOf="#+id/view7"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:srcCompat="#drawable/dot"
tools:ignore="HardcodedText" />
<LinearLayout
android:id="#+id/linearLayout2"
android:layout_width="match_parent"
android:layout_height="315dp"
android:layout_marginStart="24dp"
android:layout_marginEnd="24dp"
android:layout_marginBottom="64dp"
android:background="#drawable/rounded_bottom"
android:orientation="vertical"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/view7">
<TextView
android:id="#+id/connectTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="This tour is presented by"
android:textColor="#333"
android:textSize="12sp"
tools:ignore="HardcodedText" />
<TextView
android:id="#+id/connectSubtitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:fontFamily="#font/roboto"
android:text="Jackson Hole Land Trust"
android:textAlignment="center"
android:textColor="#color/colorTSGGreen"
android:textSize="20sp"
android:textStyle="bold"
tools:ignore="HardcodedText" />
<ScrollView
android:id="#+id/scrollView"
android:layout_width="match_parent"
android:layout_height="175dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:background="#color/transparent">
<TextView
android:id="#+id/connectMessage"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="#font/roboto"
android:text="#string/lorem_ipsum_3"
android:textColor="#333"
android:textSize="16sp" />
</LinearLayout>
</ScrollView>
<Button
android:id="#+id/learnMore"
style="#style/Widget.MaterialComponents.Button.Icon"
android:layout_width="280dp"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:drawableStart="#drawable/ic_none"
android:drawableEnd="#drawable/ic_exit_to_app"
android:onClick="buttonClick"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:text="#string/learn_more"
android:textColor="#color/loginTextColor"
android:textSize="18sp"
app:backgroundTint="#color/colorTSGGreen" />
</LinearLayout>
<ImageView
android:id="#+id/buttonBack"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="32dp"
android:contentDescription="close button"
android:onClick="iconClick"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/ic_close" />
</androidx.constraintlayout.widget.ConstraintLayout>
I'm inclined to think that it has something to do with the map view on the previous activity, but I'm not sure that could be it.
Any input would be appreciated. Thanks.

A better approach than setting a transparent background programmatically is to change its style. Especially when the background remains the same in other cases. Check out this question and its top rated answer.

Problem placing TextView on ImageView using ConstraintLayout

I am using Constraintlayout and I want to place my Textview on my Imageview, it is supposed to look like this after I'm done: https://i.stack.imgur.com/mYAws.png but each time I add constraints to the texts(Vertically and horizontally), the texts disorganizes and goes totally from how I want it to be,
Sometimes even shifting my images. I have tried severally to adjust it well to no avail
My layout.xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView 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="match_parent"
android:fillViewport="true">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".FirstFragment">
<!-- TODO: Update blank fragment layout -->
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="Current"
android:textColor="#FF3D19"
android:textSize="24sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/imageView3"
android:layout_width="358dp"
android:layout_height="337dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView3"
app:srcCompat="#drawable/orange_panel" />
<ImageView
android:id="#+id/imageView4"
android:layout_width="146dp"
android:layout_height="151dp"
android:layout_marginStart="45dp"
android:layout_marginTop="7dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageView3"
app:srcCompat="#drawable/green_panel" />
<ImageView
android:id="#+id/imageView5"
android:layout_width="146dp"
android:layout_height="151dp"
android:layout_marginTop="6dp"
android:layout_marginEnd="44dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageView3"
app:srcCompat="#drawable/pink_panel" />
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tonight"
android:textColor="#FFFFFF"
android:textSize="18sp"
tools:layout_editor_absoluteX="89dp"
tools:layout_editor_absoluteY="415dp" />
<TextView
android:id="#+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tomorrow"
android:textColor="#FFFFFF"
android:textSize="18sp"
tools:layout_editor_absoluteX="254dp"
tools:layout_editor_absoluteY="415dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>

The answer is pretty straightforward. First you should delete this lines from both text views.
tools:layout_editor_absoluteX="254dp"
tools:layout_editor_absoluteY="415dp"
Then all you need to do is add constraints like this. Below are constraints for your image
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
And the constraints for your text view would be like this.
app:layout_constraintEnd_toEndOf="#+id/image_view"
app:layout_constraintStart_toStartOf="#+id/image_view"
app:layout_constraintTop_toTopOf="#+id/image_view"
Of course you can add different constraints for the image because i do not know how do you want to position the image view in the app. But if you want a text view to be inside the image like in the link you sent then the constraints for the text view will be always like this.

It's all about tools:layout_editor_absoluteX and tools:layout_editor_absoluteY for yours textView3 and textView4. Also i think you do not know for what namespace tools exist.

Check the example below; it shows you what constraints can be used to get in the direction of your layout goals.
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView 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">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="Current"
android:textColor="#FF3D19"
android:textSize="24sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/imageView1"
android:layout_width="300dp"
android:layout_height="300dp"
android:layout_marginTop="16dp"
android:background="#00FF00"
android:textColor="#FFFFFF"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView1" />
<ImageView
android:id="#+id/imageView2"
android:layout_width="120dp"
android:layout_height="120dp"
android:layout_marginTop="16dp"
android:background="#0000FF"
app:layout_constraintStart_toStartOf="#+id/imageView1"
app:layout_constraintTop_toBottomOf="#+id/imageView1" />
<ImageView
android:id="#+id/imageView3"
android:layout_width="120dp"
android:layout_height="120dp"
android:layout_marginTop="16dp"
android:background="#FF0000"
app:layout_constraintEnd_toEndOf="#+id/imageView1"
app:layout_constraintTop_toBottomOf="#+id/imageView1" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tonight"
android:textColor="#FFFFFF"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="#+id/imageView2"
app:layout_constraintEnd_toEndOf="#+id/imageView2"
app:layout_constraintStart_toStartOf="#+id/imageView2"
app:layout_constraintTop_toTopOf="#+id/imageView2" />
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tomorrow"
android:textColor="#FFFFFF"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="#+id/imageView3"
app:layout_constraintEnd_toEndOf="#+id/imageView3"
app:layout_constraintStart_toStartOf="#+id/imageView3"
app:layout_constraintTop_toTopOf="#+id/imageView3" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>
See how this example looks: screenshot.

How to design a recyclerview with each item containing 2 buttons beside an imageview in andorid

I am trying to make a recyclerView where each of the items in the list will show an imageView with 2 buttons on the right of the imageview. I have tried but not really getting there. Some help would be really great.
Here is what i want:
What i tried:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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="wrap_content">
<ImageView
android:id="#+id/imgVw_contact"
android:layout_width="0dp"
android:layout_height="#dimen/album_cover_height_details"
android:layout_margin="5dp"
android:layout_marginStart="4dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="4dp"
android:layout_marginBottom="8dp"
android:clickable="true"
android:scaleType="fitXY"
android:src="#mipmap/ic_launcher"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/txtVw_contactName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/imgVw_contact"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
android:gravity="center"
android:text="myColors"
android:textColor="#color/album_title"
android:textSize="#dimen/album_title"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imgVw_contact" />
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:background="#drawable/ic_newok"
app:layout_constraintBottom_toBottomOf="#+id/imgVw_contact"
app:layout_constraintEnd_toEndOf="#+id/imgVw_contact"
app:layout_constraintHorizontal_bias="0.931"
app:layout_constraintStart_toStartOf="#+id/imgVw_contact"
app:layout_constraintTop_toTopOf="#+id/imgVw_contact"
app:layout_constraintVertical_bias="0.409" />
</android.support.constraint.ConstraintLayout>
and the result is:
I cant find a reason for why the images are getting round.
Also I have tried to use a drawable for button background but no matter what i create either new image asset or vector asset it becomes huge when i use it as background(as you can see in the screenshot).

Here is the design you need using ConstrainLayout -
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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/relativeLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/imgVw_contact"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="5dp"
android:layout_marginTop="5dp"
android:layout_marginEnd="5dp"
android:layout_marginBottom="5dp"
android:clickable="true"
android:scaleType="fitXY"
android:src="#mipmap/ic_launcher"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/txtVw_contactName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="5dp"
android:layout_marginEnd="8dp"
android:gravity="center"
android:text="myColors"
android:textStyle="bold"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#id/imgVw_contact" />
<Button
android:layout_marginTop="8dp"
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/ic_clear_black_24dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/btn"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/ic_check_circle_black_24dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
The corresponding layout image is -

Ok I got it. I found out the reasons behind my issues.
issue 1: There is a ic_launcher.xml(anydpi) inside mipmap which is a round cornered one. So when I was setting ic_launcher as background it takes this one .
issue 2: the images used inside the buttons get the full height width of button and becomes huge.

I have see your layout . and try to make it . Here is the code
Try this
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="200dp">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="fitXY"
android:src="#drawable/house1" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_alignParentRight="true"
android:paddingRight="5dp"
android:layout_centerVertical="true">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_highlight_off_black_24dp"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_vpn_key_black_24dp"/>
</LinearLayout>
</RelativeLayout>
</LinearLayout>

Gap between imageviews in Linear Layout that is inside the Constraint layout

I have 2 imageviews in a linear layout inside a constraint layout. There should be no gap between them, but when I run it, on some large devices it shows the gap even though I didnt give any margin or padding between them. The imageviews are with ids onboarding_image and image_line. I linear layout must be between the two guidelines showing images one upon the other without any space should take up whatever the space is left between the guideline in all devices.
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/swipe_layer"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:background="#color/blue1"
>
<ImageView
android:id="#+id/app_tour_group"
android:layout_width="70dp"
android:layout_height="9dp"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="24dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:srcCompat="#drawable/group_1" />
<RelativeLayout
android:id="#+id/next_layout"
android:layout_width="277dp"
android:layout_height="50dp"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
app:layout_constraintBottom_toTopOf="#+id/app_tour_group"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/guideline1">
<View
android:id="#+id/app_tour_next"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentBottom="true"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"
android:layout_alignParentEnd="true"
android:background="#drawable/rectangle_2" />
<TextView
android:id="#+id/next_text"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_marginTop="0dp"
android:gravity="center"
android:text="NEXT"
android:textColor="#ffffff"
android:textSize="18sp" />
</RelativeLayout>
<TextView
android:id="#+id/onboarding_title"
android:layout_width="375dp"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:gravity="center"
android:text="TextView"
android:textColor="#ffffff"
android:textSize="29sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/onboarding_description"
android:layout_width="330dp"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:gravity="center"
android:text="TextView"
android:textColor="#50287d"
android:textSize="17sp"
android:layout_marginBottom="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/onboarding_title"
app:layout_constraintBottom_toTopOf="#id/guideline2"/>
<LinearLayout
android:layout_width="315dp"
android:layout_height="0dp"
android:id="#+id/image_layout"
android:orientation="vertical"
app:layout_constraintBottom_toTopOf="#id/guideline1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_default="spread"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/guideline2"
app:layout_constraintVertical_weight="1"
android:weightSum="417"
>
<ImageView
android:id="#+id/onboarding_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:padding="0dp"
android:layout_margin="0dp"
android:layout_marginBottom="-8dip"
android:scaleType="centerInside"
android:adjustViewBounds="true"
android:layout_weight="414"
/>
<ImageView
android:id="#+id/image_line"
android:layout_width="wrap_content"
android:layout_weight="3"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
android:layout_gravity="center"
android:padding="0dp"
android:layout_margin="0dp"
android:layout_marginTop="-8dip"
app:srcCompat="#drawable/line"
android:scaleType="centerInside"
android:adjustViewBounds="true"/>
</LinearLayout>
<android.support.constraint.Guideline
android:id="#+id/guideline1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.88"
app:layout_constraintBottom_toTopOf="#+id/next_layout"
app:layout_constraintTop_toBottomOf="#+id/image_layout"/>
<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="0.245"
app:layout_constraintBottom_toTopOf="#+id/image_layout"
app:layout_constraintTop_toBottomOf="#+id/onboarding_description"
/>
</android.support.constraint.ConstraintLayout>

You say: I didn't give any margin or padding between them.
However, I can see android:layout_marginBottom="-8dip". I know you are setting also android:layout_marginTop="-8dip" to the other image. It's a little weird.
If you want to make your Images fill all the contents, use:
android:scaleType="fitxy"
or
android:scaleType="centerCrop"
in both images

Space removal on the left of image in Xml file in android studio using the recycler view

I have two images that are beside textviews.
Now the problem with this UI is that the images must be aligned to complete left side, as if coming out or sticking to the edge of the screen. However, that's not the case. I have tried scaleType and adjustViewBound, but both of them didn't work. The xml file contents have been shown below.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="wrap_content"
>
<TextView
android:id="#+id/textView_subtopic_title"
android:layout_width="245dp"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_alignTop="#+id/imageView_bulb"
android:layout_marginEnd="43dp"
android:layout_marginRight="43dp"
android:gravity="center"
android:text="Subtopic Title"
app:layout_constraintEnd_toEndOf="parent"
tools:ignore="MissingConstraints"
tools:layout_editor_absoluteY="64dp" />
<TextView
android:id="#+id/textView_count"
android:layout_width="91dp"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="#+id/textView_subtopic_title"
android:layout_marginLeft="135dp"
android:layout_marginStart="135dp"
android:text="Count"
app:layout_constraintEnd_toEndOf="parent"
tools:ignore="MissingConstraints"
tools:layout_editor_absoluteY="83dp" />
<ImageView
android:id="#+id/imageView_bulb"
android:layout_width="70dp"
android:layout_height="81dp"
android:layout_marginBottom="8dp"
android:layout_marginTop="64dp"
android:adjustViewBounds="true"
android:scaleType="fitXY"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/bulb_on" />
<ProgressBar
android:id="#+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="128dp"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/imageView_bulb"
android:layout_centerHorizontal="true"
android:outlineAmbientShadowColor="#color/colorPrimary"
android:outlineSpotShadowColor="#color/colorAccent"
app:layout_constraintEnd_toEndOf="parent"
tools:ignore="MissingConstraints"
tools:layout_editor_absoluteY="114dp" />
<TextView
android:id="#+id/textView_topic_title"
android:layout_width="242dp"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="52dp"
android:layout_marginStart="52dp"
android:layout_marginTop="23dp"
android:text="Topic Title" />
<ImageView
android:id="#+id/imageView"
android:layout_width="16dp"
android:layout_height="41dp"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginStart="0dp"
android:layout_marginTop="9dp"
android:adjustViewBounds="true"
android:scaleType="fitXY"
app:srcCompat="#drawable/blue"
android:layout_alignParentLeft="true"
android:layout_marginLeft="0dp" />
</RelativeLayout>
What should be done to remove the space on the left of the images as shown in the image?

One way you could do it is set negative margin:
android:layout_marginStart="-10dp"
or
android:paddingStart="-10dp"
change -10 to what suits you.
<ImageView
android:id="#+id/imageView"
android:layout_width="16dp"
android:layout_height="41dp"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginStart="-10dp"
android:layout_marginTop="9dp"
android:adjustViewBounds="true"
android:scaleType="fitXY"
app:srcCompat="#drawable/nodata"/>

I got the solution to this problem. It basically lay with the activity_main.xml. The recyclerview in this xml had a left padding. I just removed it, made it 0. The snippet is shown below.
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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="match_parent"
android:background="#mipmap/bg"
tools:context=".MainActivity">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerview_Main"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
I reduced the left margin to be zero in the attributes of the recyclerview.