Develop Reference

How to place correctly two views in a framelayout?

I am trying to get this design:
But my problem is that i can't get to place the red view exacly like in the photo above.
For now I'm using a framelayout but I still can't get the desire design.
Xml:
<FrameLayout
android:id="#+id/mental_health_card_h_c_ll_chat_image"
android:layout_width="42dp"
android:layout_height="42dp"
android:background="#drawable/bg_doctor_image_empty"
android:gravity="center">
<LinearLayout
android:id="#+id/mental_health_card_h_c_ll_chat_notifications_image"
android:layout_width="20dp"
android:layout_height="20dp"
android:layout_gravity="top|right"
android:background="#drawable/background_sendbird_notification"
android:gravity="center"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<com.movistar.movistarsalud.components.TeladocTextView
android:id="#+id/mental_health_card_h_c_ll_chat_notifications_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="12dp"
app:textColor="?attr/white"
app:textType="regular"
tools:text="2"
tools:textColor="?attr/white" />
</LinearLayout>
<com.movistar.movistarsalud.components.TeladocImageView
android:id="#+id/mental_health_card_h_c_chat_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:scaleType="centerCrop"
android:src="#drawable/ic_i037_chat__1_"
app:riv_oval="true" />
</FrameLayout>
And what i have until now:

You're pretty close! And I'd recommend ConstraintLayout for positioning stuff - but if you really want to use a FrameLayout (combined with a LinearLayout - I doubt it's more efficient than just using a ConstraintLayout) then I think your issue is the chat ImageView is too large.
If you imagine the FrameView as a box around your image, you have the notification dot right in the top-right corner. That shows you where the top and right edges of the frame are. You can also see that the chat image (including the blue circle) is up against those edges too - in your example pic, there's a bit of a gap.
So you'll need to experiment with setting different layout_width and height values on your ImageView. Try 40dp and see how that looks. Also you'll probably want to mess with your scaleType, you want the image to shrink, not get cropped (your version already looks a lot bigger than the example)

Simply you are missing to add elevation to your LinearLayout.
You need to add this line, and your text would be shown over the chat icon.
android:elevation="1dp"

How to go beyond the edge parent element

I have a circular image and a button icon
Lets say image is size of 20x
And button is size of 8x
I want to put the button icon in a way that 80% of its portion stays on the image view and 20% goes beyond it.
My xml code-
RelativeLyaout<
andoird.cardview.widget.Cardview<
<ImageView/>
/>
<button_icon>
layout_alignRight:ImageView
</button_icon>
ImageViw and button_icon overlaps but not that way I want.
80% portion of the button stays behind the image view that i cant see and the rest 20% of the button that goes beyond the image view is visible
This is for my Android studio app. I things above code is less time consuming.
If you need full code i can provide that too.

you can't exceed parents bounds. but you can introduce one extra layer which will hold both your Views and second one may cover part of first one. some basic example with FrameLayout
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<View
android:layout_width="100dp"
android:layout_height="100dp"
android:background="#097267">
<View
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_margin="40dp"
android:background="#A9C26A">
</FrameLayout>
also be aware that elevation and translationZ XML attributes may change order of drawing (first View will be drawn on top of second and will cover it). e.g. Button have some elevation set by default, also CardView (setCardElevation(float)) - additionally (mainly?) this makes some small shadow under these Views

Try this code... I have added constraint layout and inside it i have added button overlapping the image.
You can change the size according to your requirements !!
<?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">
<de.hdodenhof.circleimageview.CircleImageView
android:id="#+id/circleImageView4"
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_marginTop="60dp"
android:src="#drawable/blue1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.057"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.appcompat.widget.AppCompatButton
android:layout_width="60dp"
android:layout_height="40dp"
android:layout_marginTop="50dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.166"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="#+id/circleImageView4" />
</androidx.constraintlayout.widget.ConstraintLayout>

Can't center button in constraint layout

This question may have been asked a million times and seem trivial but i still do not understand the logic behind it after reading about 100 of answers.
I have this ultra simple layout XML
<?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">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
</androidx.constraintlayout.widget.ConstraintLayout>
From my understanding if i set opposing constraints the render engine interprets them automatically as percentage... i mean right ?
If no specific margin or anything is set then it evens out the distances. This would clearly mean that the button should tae a centered position inside the view. But it doesnt....
I dont understand it. i want to center with WITHOUT SETTING A MARGIN since a margin, from my understanding, is something independent of the constraint. It works within a constraint. but nevertheless i set a margin of 50 on each side. once a margin is set on opposing sides the engine should automatically render it as percentage.... right ?
So this XML:
<?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">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="50dp"
android:layout_marginLeft="50dp"
android:layout_marginTop="50dp"
android:layout_marginEnd="50dp"
android:layout_marginRight="50dp"
android:layout_marginBottom="50dp"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
</androidx.constraintlayout.widget.ConstraintLayout>
should say something like "the constraint is 50% to left right top and bottom" which essentially again is exactly the middle. Of course this is again not working. The engine interprets it as absolute value and the button is in another awkward position:
So how to do this ??
What I DON'T WANT TO DO:
Adjust it with some kind of Guideline or Bias.
I want the plain thing.
Just 4 constraints (4 lines inside the xml) and a button that is in the middle of the screen on any device.
Maybe someone can share some insight ?

You should delete these two attributes:
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintVertical_bias="0.0"
As you can see the official reference, default bias is fifty-fifty (50% = 0.5).
For example the following will make the left side with a 30% bias
instead of the default 50%, such that the left side will be shorter,
with the widget leaning more toward the left side (Fig. 5):

Constraint layout: Cannot separate elements and keep them all on screen

I have a simple constraint layout like this:
<?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"
tools:context=".MainActivity">
<ListView
android:id="#+id/main_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="#id/rescan"
/>
<android.support.v7.widget.AppCompatButton
android:id="#+id/rescan"
android:layout_width="wrap_content"
android:text="#string/rescan_button"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintBottom_toBottomOf="parent"
/>
</android.support.constraint.ConstraintLayout>
Despite the layout_constraintBottom_toTopOf="#id/rescan", the listview potentially extends halfway through the button.
To try and correct that, I added hardcoded dimensions (which I prefer not to do); to the listview:
android:layout_marginBottom="50sp"
And to the button:
android:layout_height="40sp"
android:textSize="20sp"
android:layout_margin="10sp"
However, I then got this (emulator pic, the design view also corresponds to this):
The button is halfway off the screen.
So I decided to remove the hardcoded dimensions and use a barrier. The developer page is ambiguous about how barrierDirection is supposed to work, but this
"constraintlayout.com" example makes it clear the direction should be the side you want the barrier on in relation to the elements listed in referenced_ids. Based on that, here's what I have inside the constraint layout:
<ListView
android:id="#+id/main_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="#id/bottomBarrier"
/>
<android.support.constraint.Barrier
android:id="#+id/bottomBarrier"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:barrierDirection="top"
app:constraint_referenced_ids="#id/rescan"
/>
<android.support.v7.widget.AppCompatButton
android:id="#+id/rescan"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/rescan_button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintHorizontal_bias="0.5"
/>
But things are not really getting better...
It's impossible to tell, but here the barrier is at the very bottom. Which explains why the listview, with Bottom_toTopOf the barrier, also now extends all the way to the bottom.
However, that makes the whole barrier, who's direction is top and who's constrained id is the button, totally pointless. In no sense is it keeping the listview on one side and the button on the other. It's below both of them.
Even more berserk: If I change the direction to bottom and leave everything else as it, the barrier jumps to the very top, the listview jumps halfway off the screen upward, and the button stays in place.
I'm totally flummoxed. My two biggest questions are:
Why, in the first picture, does the listview extend halfway through the button, when it is set bottom-to-top of the button?
Why, in the last picture, is the barrier, with a direction of "top" and referencing the button id, below the button?

1.
Your ListView's height is set to wrap_content which means the view will compute its own size and constraints will not limit the dimension. ConstraintLayout-1.1.0 introduced new attributes that allow using wrap_content yet keep enforcing the constraints to limit the specified dimension. These attribues are:
app:layout_constrainedWidth="true"
app:layout_constrainedHeight="true"
2.
As for the Barrier, there's an error in the way you're referencing the view's id:
app:constraint_referenced_ids="#id/rescan"
This should be changed to:
app:constraint_referenced_ids="rescan"

XML background image in layout

This is ridiculous, no error, I already did the same on some other projects and works fine but it still shows nothing...
Someone knows why my background image is fine in the editor (in the Android Studio editor it shows the background image), but when I run the app on my device, it shows the only white background with just my 2 buttons...
<?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"
tools:context="com.example.ale.mediaspectrumplayer.MainActivity"
android:background="#drawable/background">
<Button
android:id="#+id/ID_MediaPlayer_Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="48dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="24dp"
android:text="#string/main_MediaPlayer"
app:layout_constraintBottom_toTopOf="#+id/ID_SpectrumView_Button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="#+id/ID_SpectrumView_Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="48dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="16dp"
android:text="#string/main_SpectrumView"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.25"
app:layout_constraintStart_toStartOf="parent" />
</android.support.constraint.ConstraintLayout>
Neither with code it works and I dunno why (layout.setBackgroundResource(R.drawable.background), and neither with image view and scale fitXY...that's absurd

Sometimes, if the image you are using to set as background is of high resolution or is heavy, system just avoids loading it to save the memory. In case you want that image in the background of the whole content, you have to set an image view whose height and width matches that of the parent layout. Then use an image loading library eg : Picasso, Glide etc to efficiently load the high resolution image in that ImageView without burdening the system

Have you tried using the android:scaleType attribute? This can change the position of the background image to cover the screen, sometimes if the image is too small it won't show up. Setting scaleType to center or centerCrop might help.
Here's the documentation: https://developer.android.com/reference/android/widget/ImageView.ScaleType.html

try Changing parent layout to RelativeLayout or any other layout.