Develop Reference

Separate image from AppCompatTextView

I have a Linear Layout with a list of six horizontal button in column. Each Button is defined as a AppCompactTextView since I need to place two images on it, as you can see in the following image:
What I need to do is separate the drawableStartCompat image (the one on the left) from the AppCompactTextView, without changing its position. I would like to keep it separated from the button. How can do it? I was thinking to wrap it with the button in a View but I do not know how to manage it. This is the code of one of the six element of the list:
<androidx.appcompat.widget.AppCompatTextView
android:id="#+id/view_top_up_button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#android:color/transparent"
android:text="#string/placeholder"
android:textColor="#color/black"
app:drawableEndCompat="#drawable/ic_arrow_right_small_black"
app:drawableStartCompat="#drawable/ic_menu_charge" />

You can wrap the Imageview & TextView into any viewgroup you like & create one view like this, which gives you flexibility to maintain margin postion etc for your view:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:orientation="horizontal">
<ImageView
android:id="#+id/leftImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:src="#drawable/ic_android" />
<TextView
android:id="#+id/tvTitle"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_weight="1"
android:padding="8dp"
android:text="Boost"
android:textSize="16sp"
android:textStyle="bold" />
<ImageView
android:id="#+id/rightImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:src="#drawable/ic_arrow_right" />
</LinearLayout>
</LinearLayout>
Output:
You can even go ahead & create a custom/compound view out of your layout.

Create custom button out of horizontal LinearLayout, which contains ImageView, Button and perhaps another ImageView for the image on the right.

Make ViewPager Fill The Remaining Space In a ConstraintLayout

I have the following XML code , I couldn't make 'summaryViewPager' fill the remaining space vertically, until the bottom of the screen :
<?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"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.card.MaterialCardView
android:id="#+id/mainCardView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="10dp"
android:layout_marginRight="10dp"
android:background="#666266"
android:padding="10dp"
app:cardCornerRadius="20dp"
app:layout_constraintEnd_toEndOf="parent"
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:layout_marginStart="3dp"
android:layout_marginLeft="3dp"
android:layout_marginTop="2dp"
android:text="#string/category"
android:textColor="#FFBA93"
android:textSize="20sp"
android:textStyle="bold"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</com.google.android.material.card.MaterialCardView>
<com.google.android.material.card.MaterialCardView
android:id="#+id/cardView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="10dp"
android:layout_marginRight="10dp"
android:background="#666266"
android:padding="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/mainCardView">
<Button
android:id="#+id/shareButton"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginStart="5dp"
android:layout_marginLeft="5dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="5dp"
android:layout_marginRight="5dp"
android:background="#drawable/ic_share"
app:layout_constraintEnd_toStartOf="#+id/copyButton"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/seenImageView"
android:layout_width="20dp"
android:layout_height="20dp"
android:layout_marginStart="3dp"
android:layout_marginLeft="3dp"
android:layout_marginTop="15dp"
android:layout_marginEnd="5dp"
android:layout_marginRight="5dp"
android:contentDescription="#string/todo"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toEndOf="#+id/favoriteButton"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/unseen" />
</com.google.android.material.card.MaterialCardView>
<androidx.viewpager2.widget.ViewPager2
android:id="#+id/summaryViewPager"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginTop="2dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/cardView2" />
</androidx.constraintlayout.widget.ConstraintLayout>
The above code doesn't show the PageViewer at all below cardView2 , however when I set android:layout_height="500dp it does show PageViewer, but it doesn't fill the whole screen.

Initial Thoughts
I copy pasted your Layout into Android Studio 4.x, replaced all #string references with "something", and all #drawables with an existing one (from #android:drawable/) so my layout would render.
From what I see, it looks correct:
I noticed some inconsistencies in your Layout.
CardView Number 1 (top)
Careful with Padding on a CardView (don't know your min/max API so, not sure if this applies to you).
Your CardView has no constrain for its BOTTOM, it's left to "whatever size you compute after wrapping" (Height = wrap, Bottom_To = null).
This ^ means that for the CardView to have a height, all its innerwidgets must compute their sizes, so the top card view knows how much size + margin + padding it needs. It doesn't depend on OTHER widgets (that are not children) because its constrains are all to the parent. (rather it only needs its parent).
CardView Number 2 (bottom)
This cardView wraps all its dimensions but has the same issue as the one above, it doesn't constraint its height (except to be pinned at the bottom of the previous one, CardView 1). Again, this is fine, so as long as nobody depends on this (which is not true). This one has to wait on more widgets to know its size, because it has to wait on the CardView1 to know how much space is left, and also needs to know how much its children need. It's not too hard because both (the ImageView and the Button) have fixed sizes (20 and 30 dp respectively) + margins/padding.
The children of a MaterialCardView cannot/should not/must not use constraints because a CardView is not a ConstraintLayout, rather a glorified FrameLayout, which can only hold ONE child (or if it has more, it will put them on on top of the other). So all those constraints (for the shareButton and seenImageView) are ignored.
The solution to the above, is to have an inner ConstraintLayout as the sole child of a CardView, and inside this inner CL, put all your children and their constraints. The inner ConstraintLayout should have its width/height as either wrap_content or match_parent so they use the constraints of the parent. Since htey have fixed sizes, this is not an issue. (and if they didn't it wouldn't be an issue, but would need another measure pass).
Regardless of this, this second CardView is able to calculate its height, because its children are reporting a size of 20+30 (overlapped) + 15 margin top (image) so.. all this combined is likely 45dp~ of height (since they overlap only the biggest numbers apply here).
All the constraints are ignored for these two children.
ViewPager (bottom)
Finally we reach the VPager. This viewPager is match_parent for its width (since you have constraints to the start/end, you should just use 0dp). And it has wrap_content for its height.
layout_height=wrap_content -> this is a problem here. Because the viewPager doesn't (at the time of layout pass/measure) yet know what its contents are going to be. So you probably want this to be 0dp and let the ViewPager use all available space after the above has been calculated.
The marginTop you have here, will not work as it is, because the CardView 1 and 2 have no bottom constrain, so this one would have to create yet another layout/measure pass after it's all said and done to be able to apply a margin (that's how it works).
Ok Enough Rant - what can you do?
I'd "fix" the layout by adding the correct constraints and -if needed- use a VerticalChain and biasing for all widgets.
I'd fix the middle (Cardview 2) contents by wrapping the textview and imageView in a ConstraintLayout.
I'd remove left/right and replace with start/end (unless you target API 16 or below).
I'd set the ViewPager to 0dp on both dimensions.
The children of your CardView2 refer to copyButton and favoriteButton but these don't exist in the Layout you pasted, so I assume you have more buttons there).
Full Version (modified)
And in case you wonder, here's what I did ( I added a color to the VP's background so it was easier to "see").
<?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"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.card.MaterialCardView
android:id="#+id/mainCardView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="10dp"
app:layout_constraintVertical_chainStyle="packed"
android:background="#666266"
android:padding="10dp"
app:cardCornerRadius="20dp"
app:layout_constraintBottom_toTopOf="#id/cardView2"
app:layout_constraintEnd_toEndOf="parent"
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:layout_marginStart="3dp"
android:layout_marginTop="2dp"
android:text="Category"
android:textColor="#FFBA93"
android:textSize="20sp"
android:textStyle="bold" />
</com.google.android.material.card.MaterialCardView>
<com.google.android.material.card.MaterialCardView
android:id="#+id/cardView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="10dp"
android:layout_marginRight="10dp"
android:background="#666266"
android:padding="10dp"
app:layout_constraintBottom_toTopOf="#id/summaryViewPager"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/mainCardView">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/innerCardView2Root"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Button
android:id="#+id/shareButton"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginStart="5dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="5dp"
android:background="#android:drawable/ic_menu_share"
app:layout_constraintEnd_toStartOf="#+id/seenImageView"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/seenImageView"
android:layout_width="20dp"
android:layout_height="20dp"
android:layout_marginStart="3dp"
android:layout_marginTop="15dp"
android:layout_marginEnd="5dp"
android:contentDescription="#null"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/shareButton"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#android:drawable/ic_menu_search" />
</androidx.constraintlayout.widget.ConstraintLayout>
</com.google.android.material.card.MaterialCardView>
<androidx.viewpager2.widget.ViewPager2
android:id="#+id/summaryViewPager"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="2dp"
android:background="#color/colorSecondary"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/cardView2" />
</androidx.constraintlayout.widget.ConstraintLayout>

Wrap right-aligned view when there is no space

I have 2 views in a layout - TextView and Button. TextView is aligned/anchored to the left side and the button is to the right side.
What I'm trying to achieve is the natural "wrap behavior" of the Button. When TextView will be wide enough so that there won't be space for the button (in the same line), it should move below the TextView, while still anchored to the right.
Here are 3 scenarios for the layout which I want to achieve:
I was trying to make this with FlexBoxLayout, but the button appears on the left side after wrapping.
<com.google.android.flexbox.FlexboxLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:flexDirection="row"
app:flexWrap="wrap"
app:justifyContent="space_between"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="text text"
android:gravity="start"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="end"
android:text="Button"
/>
</com.google.android.flexbox.FlexboxLayout>
So how can I do that? It doesn't need to be FlexBox, I can use any layout, even 3rd party.

Use justifyContent="flex_end" in the parent and set layout_flexGrow to the children like this works for me.
<com.google.android.flexbox.FlexboxLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="300dp"
android:layout_height="wrap_content"
app:flexDirection="row"
app:flexWrap="wrap"
app:justifyContent="flex_end">
<TextView
android:id="#+id/textview2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="10dp"
android:text="blah blah"
app:layout_flexGrow="1" />
<TextView
android:id="#+id/textview3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="10dp"
android:text="( . )( . )"
app:layout_flexGrow="0" />
</com.google.android.flexbox.FlexboxLayout>

No need for a 3rd party layout.
ConstraintLayout should be more than enough - with a small tweak in code.
Your TextView will have straightforward constraints, set to parent layout (start, top, end).
<?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:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:tools="http://schemas.android.com/tools">
<TextView
android:id="#+id/text"
android:layout_width="wrap_content"
android:layout_height="48dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:text="Text text text text text text" />
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="#+id/text" />
</android.support.constraint.ConstraintLayout>
In the code, just check the width of the TextView and compare it with the width of the parent (basically check it should overlap with the button).
If it does change(you will have to do this in code but this is the principle):
app:layout_constraintTop_toTopOf="#+id/text"
to
app:layout_constraintTop_toBottomOf="#+id/text"
If you need to do this dynamically ConstraintLayout has neat feature "Keyframe animations" that creates awesome looking animations when you are changing constraints.

Doesn't seem like there is a way to do it with Flexbox. I would just do it programmatically when you've inflated the resource (in onCreateView() or something like that). The parent of both of the views would be a RelativeLayout, with the Button aligned to the TextView top when the widths combined don't exceed the width of the RelativeLayout, and aligned to the bottom of the TextView when the widths are larger than that.

Placing button that overlaps two views in Android

I would like to place a button like so (overlapping two views, centered):
I tried to solve the issue with a RelativeLayout and a negative margin but somehow I can't overlap the two views. Instead the button always get's placed at the bottom of the image view. Any ideas?
Thanks in advance for the help!
Here my code:
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/tour_image"
android:layout_width="match_parent"
android:layout_height="220dp" />
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:layout_marginBottom="-35dp"
android:layout_marginEnd="16dp">
<Button
android:id="#+id/go_to_map_button"
style="#style/FloatingActionButton.Light"
android:layout_width="70dp"
android:layout_height="70dp"
android:drawableTop="#drawable/ic_directions_walk_color_24dp"
android:paddingTop="12dp"
android:text="#string/tour_button_show_map"
android:textAllCaps="true"
android:textAppearance="#style/p.Small"
android:textColor="#color/primary_main" />
</RelativeLayout>
</RelativeLayout>
The code results in this layout:

In my opinion, the best way to handle this would be to convert your existing top-level RelativeLayout into a ConstraintLayout. Developer guide for ConstraintLayout is available here: https://developer.android.com/training/constraint-layout/index.html
Once you have a top-level ConstraintLayout, you can position a view on the edge of two views by constraining your button's top and bottom to the view edge:
<android.support.constraint.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">
<View
android:id="#+id/top"
android:layout_width="0dp"
android:layout_height="100dp"
android:background="#caf"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"/>
<View
android:id="#+id/bottom"
android:layout_width="0dp"
android:layout_height="100dp"
android:background="#fac"
app:layout_constraintTop_toBottomOf="#+id/top"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"/>
<View
android:id="#+id/overlap"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_marginRight="24dp"
android:background="#fff"
app:layout_constraintTop_toBottomOf="#+id/top"
app:layout_constraintRight_toRightOf="#+id/top"
app:layout_constraintBottom_toBottomOf="#+id/top"/>
</android.support.constraint.ConstraintLayout>
The important part of this code is that the "overlap" view has these two constraints:
app:layout_constraintTop_toBottomOf="#+id/top"
app:layout_constraintBottom_toBottomOf="#+id/top"
These are saying "match my top edge to the other view's bottom edge" and "match my bottom edge to the other view's bottom edge". Obviously that's impossible, since the view has a non-zero height, and so ConstraintLayout will automatically position it so that it is centered on the other view's edge. Further details are available in the developer guide I linked above.

Android studio programming

I am developing an android application to display current news or events. But, starting the interface with the toolbar and the login page, I have a problem with ConstraintLayout. I do not know why but the textview and imageview are red while in RelativeLayout and LinearLayout it works.
<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"
tools:context="com.exemple.rivoramampiandra.appsname.MainActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Connexion"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.079" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="match_parent" />
<EditText
android:id="#+id/editText"
android:layout_width="367dp"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPersonName"
android:text="Name"
tools:layout_editor_absoluteX="9dp"
tools:layout_editor_absoluteY="85dp" />

Seeing your code would help a lot in solving the problem, some guesses though might be:
Constraints were not added to the TextView and ImageView as each view place in the UI must be constrained to its parent or child in some way
https://developer.android.com/training/constraint-layout/index.html#add-a-constraint
If you converted the ConstraintLayout to a RelativeView or a LinearLayout. It is possible the attributes are left in the XML of the constrained attributes within the children views inside your layout. thosapp:layout_constraintBaseline_toBaselineOf="#+id/text_title"
https://medium.com/exploring-android/exploring-the-new-android-constraintlayout-eed37fe8d8f1
Hope any of this solved your problem!