Develop Reference

In Android Studio, text does not appear on top of an image

I'm doing a small project on Android Studio, and I've put a picture as a dark blue background.
I inserted white text on top of this dark blue figure, but the white color in the letters still doesn't show.
The Graphical Interface. See that I put the color white, but it still doesn't show up.
Please, check out:
Please, can anyone help to
[1]: https://i.stack.imgur.com/iTtiS.png
Source-code in the XML:
[2]: https://i.stack.imgur.com/u6AIU.png
Please, what to do to the white text appear on the top of the image in Android Studio?
Whole XML Layout:
<?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"
tools:context=".MainActivity">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="410dp"
android:layout_height="250dp"
android:color="#color/white"
android:foreground="#drawable/home_bg"
android:textSize="30dp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Encontre o seu próximo destino!"
android:textColor="#android:color/white"
android:textSize="20dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.32"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.233" />
<TextView
android:id="#+id/textView2"
android:layout_width="176dp"
android:layout_height="41dp"
android:layout_marginBottom="64dp"
android:text="Procurar Destinos"
android:textColor="#FFFFFF"
android:textColorHighlight="#color/white"
android:textSize="20dp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.324"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView"
app:layout_constraintVertical_bias="0.742" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

Ok I think the problem is that you've set the foreground of the constraint layout instead of the background.
Try this:
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="410dp"
android:layout_height="250dp"
android:color="#color/white"
android:background="#drawable/home_bg"
android:textSize="30dp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">

How do I scroll the screen with the RecyclerView inside with RecyclerView load items step by step?

I have gallery page in my project. There are different view types in this page like RecyclerView - TextView - ImageView. If I set height "wrap_content" of RecyclerView, my RecyclerView loads all items. That's freeze to my view, because of some galleries has too many items. I want to load items step by step. But If I set height "match_constraint" of RecyclerView, my gallery page has 2 scroll (One of them is ScrollView, one of them is RecyclerView). So all view couldn't scroll with together. How do I scroll the screen with the RecyclerView inside with RecyclerView load items step by step?
Actually my XML is too long so I didn't add some views in following code.
<?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:id="#+id/detail_fragment_scroll"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#android:color/transparent"
android:clipChildren="false"
android:clipToPadding="false"
android:fillViewport="true"
android:fitsSystemWindows="false"
android:focusable="true"
tools:context=".DetailActivity">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/detail_fragment_constraint"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white"
android:focusable="true"
android:scrollbars="none">
<TextView
android:id="#+id/feed_detail_category"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="12dp"
android:layout_marginTop="12dp"
android:paddingLeft="8dp"
android:paddingTop="2dp"
android:paddingRight="8dp"
android:paddingBottom="2dp"
android:textColor="#android:color/black"
android:textSize="12sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="parent” />
<TextView
android:id="#+id/feed_detail_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
app:layout_constraintBottom_toBottomOf="#+id/feed_detail_category"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="#+id/feed_detail_category" />
<TextView
android:id="#+id/feed_detail_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:paddingLeft="8dp"
android:paddingTop="8dp"
android:paddingRight="8dp"
android:paddingBottom="8dp"
android:textColor="#android:color/black"
android:textSize="24sp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/feed_detail_category" />

 
 <androidx.recyclerview.widget.RecyclerView
android:id="#+id/comment_recycler_view"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:visibility="visible"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/feed_detail_title” />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>

Use Pagination library from Android Jetpack.
Check from official documentation here.
You can also find a good tutorial Here

ConstraintLayout: Why does the height of a view affect its children?

I am building an app in Android Studio and have a problem and I do not know why it happens and how to solve it. This is my code:
<?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="#f4f4f4"
tools:context=".MainActivity">
<TextView
android:id="#+id/textView"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="144dp"
android:gravity="center"
android:shadowColor="#000000"
android:text="#string/title"
android:textColor="#eadca6"
android:textSize="60sp"
android:textStyle="bold"
app:layout_constraintBottom_toTopOf="#+id/button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.500"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
<Button
android:id="#+id/button"
android:layout_width="342dp"
android:layout_height="0dp"
android:layout_marginStart="160dp"
android:layout_marginLeft="160dp"
android:layout_marginTop="260dp"
android:layout_marginEnd="160dp"
android:layout_marginRight="160dp"
android:background="#eadca6"
android:text="#string/all_quotes"
android:textAllCaps="false"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="#+id/button2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.500"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView" />
<Button
android:id="#+id/button2"
android:layout_width="342dp"
android:layout_height="0dp"
android:layout_marginStart="160dp"
android:layout_marginLeft="160dp"
android:layout_marginTop="20dp"
android:layout_marginEnd="160dp"
android:layout_marginRight="160dp"
android:layout_marginBottom="50dp"
android:background="#eadca6"
android:text="#string/favorite_quotes"
android:textAllCaps="false"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.500"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/button" />
</androidx.constraintlayout.widget.ConstraintLayout>
However, if you run the code like this, the title will be cut off in half. But the 2 buttons will have a normal size. If I use wrap_content on the textview, the TextView will be displayed normally but the buttons height will also only be as big as the text inside (like inherit the wrap content), even if I don't write wrap_content in the buttons field. The LayoutEditor tells me everything is fine, but when I run the app, those design "errors" happen.

I added some modification in your code and added a screenshot for this code
<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="#f4f4f4"
tools:context=".MainActivity">
<TextView
android:id="#+id/textView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="144dp"
android:shadowColor="#000000"
android:text="title"
android:textAlignment="center"
android:textColor="#eadca6"
android:textSize="60sp"
android:textStyle="bold"
app:layout_constraintBottom_toTopOf="#+id/button"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.500"
app:layout_constraintVertical_bias="0.0" />
<Button
android:id="#+id/button"
android:layout_width="342dp"
android:layout_height="wrap_content"
android:layout_marginTop="260dp"
android:layout_marginLeft="35dp"
android:layout_marginRight="35dp"
android:background="#eadca6"
android:text="all_quotes"
android:textAllCaps="false"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="#+id/button2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView" />
<Button
android:id="#+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:layout_marginTop="23dp"
android:layout_marginBottom="50dp"
android:layout_marginLeft="35dp"
android:layout_marginRight="35dp"
android:background="#eadca6"
android:text="favqussdi"
android:textAllCaps="false"
android:textSize="20sp"
app:layout_constraintTop_toBottomOf="#+id/button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
as you can see i change the following:
android:layout_height change value into wrap_content;
android:layout_width change value into match_parent;
added android:paddingTop="10dp" and android:paddingBottom="10dp" in buttons;
modify layout_marginLeft and layout_marginRight;
remove some redundant codes and also avoid adding static number as possible. Hope i help you in small way ^^

You want to know what is wrong with your code so I will start with some explanation before writing code:
TL;DR:
Don't use fixed size on your views, you can use app:layout_constraintHeight_percent="0.xx" with
app:layout_constraintWidth_percent="0.yy" and Guidelines.
Full answer
Different phones got different screen size, in your layout, you are using fixed size on your views (fixed size is android:layout_marginTop="144dp" for example) and the result is that what may look good on one screen (your android studio preview screen) will not look good on another screen (your actual phone), and this is why you are getting design "errors".
You cant guarantee full layout responsability when using wrap_content as well, for example, if you will take a very large image and put it on your views it wont look the same on different devices.
If you already using constraintLayout here are some tools that can help you achieve a responsive layout that will fit in size to all screen sizes.
For example, look at this layout:
<?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="#f4f4f4"
tools:context=".MainActivity">
<TextView
android:id="#+id/textView"
android:layout_width="0dp"
android:layout_height="0dp"
android:gravity="center"
android:shadowColor="#000000"
android:text="title"
android:textColor="#eadca6"
android:textSize="60sp"
android:textStyle="bold"
app:layout_constraintBottom_toTopOf="#+id/guideline3"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.15"
app:layout_constraintWidth_percent="0.9"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="#+id/button"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#eadca6"
android:text="all_quotes"
android:textAllCaps="false"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="#+id/guideline2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.1"
app:layout_constraintHorizontal_bias="0.500"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintWidth_percent="0.9" />
<Button
android:id="#+id/button2"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#eadca6"
android:text="favorite_quotes"
android:textAllCaps="false"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.1"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/button"
app:layout_constraintWidth_percent="0.9" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline2"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.8" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline3"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.2" />
</androidx.constraintlayout.widget.ConstraintLayout>
This layout will look like this:
What I did in this layout:
I got rid of every single fixed size on my views and gave them fixed size like, something like this on the view:
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintHeight_percent="0.15"
app:layout_constraintWidth_percent="0.9"
This view will be equal to 15% of the screen height and 90% of its width in size, it will be responsive for different layouts.
I managed the position of the views by using Guidelines, for example:
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline3"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.2" />
This guideline will be placed at the top 20% of the screen.
Something extra - you can use ssp /
sdp if you want to scale the size of your views (In your case I would use ssp library to scale your text size on your views).

Try this code in your xml. This way buttons and text will look normal.
<?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="#f4f4f4"
tools:context=".MainActivity">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:shadowColor="#000000"
android:text="#string/title"
android:textColor="#eadca6"
android:textSize="60sp"
android:textStyle="bold"
app:layout_constraintBottom_toTopOf="#+id/group"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/button"
android:layout_width="342dp"
android:layout_height="120dp"
android:background="#eadca6"
android:text="#string/all_quotes"
android:textAllCaps="false"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="#+id/button2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="#id/group" />
<Button
android:id="#+id/button2"
android:layout_width="342dp"
android:layout_height="120dp"
android:layout_marginTop="20dp"
android:background="#eadca6"
android:text="#string/favorite_quotes"
android:textAllCaps="false"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="#id/group"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/button" />
<androidx.constraintlayout.widget.Group
android:id="#+id/group"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:constraint_referenced_ids="button,button2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView" />
</androidx.constraintlayout.widget.ConstraintLayout>

How to fix a view from going off of a page when it is constrained to a card view

I have recently converted over an android project into androidx and I am having issues with trying to stop views going off of the page. My layout is as follows, a Constraint Layout that contains a Card View and a Text View. Within this Card View I have a Constraint Layout that contains the Text View. Outside of the Card View I have a Button which is constrained to the Card View.
The issue with this is that when I run the program the Card View goes off of the screen and the button moves all the way to the top even though they are all constrained properly.
I will show below the code I am using to achieve this and an image of my result on the emulator.
Here is the layout in the editor [1]: https://imgur.com/a/0FLa1IK
Here is the layout shown on the Emulator [2]: https://imgur.com/a/SsvKiOG
Any help would be greatly appreciated.
<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">
<androidx.cardview.widget.CardView
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toTopOf="#+id/materialButton"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:layout_marginBottom="16dp"
android:text="Text View Test"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<Button
android:id="#+id/materialButton"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="256dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Your layout is getting pushed because of this line:
android:layout_marginBottom="256dp"
Different phones got different screen size, in your layout you are using fixed size on your view ("256dp") and it makes your layout non-responsive.
So what may look good on your preview may not look the same on a real phone.
If you want to place some view anywhere on your screen and keep it responsive I recommend using guidelines, something like this:
<androidx.constraintlayout.widget.ConstraintLayout
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.cardview.widget.CardView
android:id="#+id/cv_text"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_margin="8dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toTopOf="#+id/materialButton"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Text View Test"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.cardview.widget.CardView>
<Button
android:id="#+id/materialButton"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toTopOf="#+id/guideline13"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline13"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent=".5" />
</androidx.constraintlayout.widget.ConstraintLayout>
And it will look like this:

I'm not so sure about android x but the constraint layouts are used for removing the nested layouts so, you should not be using constraint layout inside card view. Try this code as a reference. It might help.
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto">
<android.support.v7.widget.CardView
android:id="#+id/cv_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="8dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintTop_toBottomOf="parent">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:layout_marginBottom="16dp"
android:text="Text View Test"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.v7.widget.CardView>
<Button
android:id="#+id/materialButton"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="280dp"
android:layout_marginEnd="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cv_text" />
</android.support.constraint.ConstraintLayout>

please remove this line from button attribute :
android:layout_marginBottom="256dp"
your are just pushing to button to the top by setting the margin_bottom , and why it's shown on the preview and not on the device just because of the different screen size

How to make texts complete on a new line and make a layout with transparent color

I just create simple grid view like this
all I need as you see the texts with long name I want it to complete the text in a new line not going to the other relative layout as I need also the relative layout with id/rlTXTnme with a green color but with transparent green color for example thats the image view in the parent relative layout should be showed like this grid item Example
and this is my XML File
<?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="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical">
<RelativeLayout
android:background="#ffffff"
android:layout_height="125dp"
android:layout_width="125dp"
tools:layout_conversion_absoluteX="5dp"
tools:layout_conversion_absoluteY="5dp"
tools:layout_conversion_absoluteWidth="170dp"
tools:layout_conversion_absoluteHeight="170dp"
tools:layout_editor_absoluteY="0dp"
tools:layout_editor_absoluteX="0dp">
<ImageView
android:id="#+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="#drawable/ssttll"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true" />
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="65dp"
android:layout_alignParentBottom="true"
android:background="#dcffbc"
android:id="#+id/rlTXTnme"
android:layout_toStartOf="#+id/relativeLayout">
</RelativeLayout>
<RelativeLayout
android:layout_width="35dp"
android:layout_height="75dp"
android:background="#f9762f"
android:id="#+id/relativeLayout"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:layout_below="#+id/button">
</RelativeLayout>
<TextView
android:id="#+id/textView8"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25dp"
android:text="0"
android:textColor="#ffffff"
android:textStyle="bold"
android:layout_marginTop="15dp"
android:layout_below="#+id/button"
android:layout_alignStart="#+id/relativeLayout" />
<Button
android:id="#+id/button"
android:layout_width="50dp"
android:background="#ff2f2f"
android:layout_height="75dp"
android:layout_alignParentEnd="true"
android:layout_alignParentTop="true"
android:text="-"
android:layout_alignStart="#+id/relativeLayout"
android:layout_above="#+id/rlTXTnme" />
</RelativeLayout>
<TextView
android:id="#+id/menuTVGrid"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="TextView"
android:textColor="#000000"
android:textSize="10dp"
android:textStyle="bold"
tools:layout_editor_absoluteX="0dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintVertical_bias="0.601" />
</android.support.constraint.ConstraintLayout>
Sorry for my bad Englishand sorry if any thing is unclear

You can use a linearLayout and set weights to the layouts.
And for the transparency of the background, android accepts colors in AARRGGBB format where AA is the percent value of transparency needed. A good doc for percent-to-hex conversion can be found on this SO post.
Posting the edited layout in sometime
For transparency: if for 20% transparency:
android:background="#33dcffbc"