Develop Reference

Horizontal Layout messed up when using Jetpack Fragment Navigation

Android dev beginner here. I've followed a tutorial for fragment-based navigation. I'm running into troubles when changing device orientation. It works fine on a real device, but in the emulator it is broker.
I've read some things about the view being re-rendered on device orientation change, but in my case the entire layout gets messed up, including the top bar as well as the bottom bar (back, etc.). A screenshot and code included below.
Note: layout looks completely fine when seeing it in design tab of XML layout file.
This is what it looks like in a vertical orientation:
Code for main activity and main fragment is below:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<fragment
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:defaultNavHost="true"
app:navGraph="#navigation/nav_graph" />
</androidx.constraintlayout.widget.ConstraintLayout>
and my main fragment is this one:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainFragment"
android:id="#+id/parentLayout">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="30dp"
android:gravity="center">
...some stuff here...
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

=> this looks incorrect:
android:layout_width="0dp"
android:layout_height="0dp"
Try to follow this example :
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent">
<fragment android:name="com.example.news.ArticleListFragment"
android:id="#+id/list"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="match_parent" />
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

Android: Make an overlay match content height instead of expanding parent's height

I have the following code:
<?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">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/imageView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:srcCompat="#tools:sample/avatars[1]" />
<!-- This is the element of interest.
View is actually a custom element, but for this example, View has same behavior -->
<View
android:id="#+id/MyView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#A4D38D14" />
</FrameLayout>
</android.support.constraint.ConstraintLayout>
Which results in the following. Orange is the size of the View of interest. No-matter what I try, it seems I cannot get the View to not expand the parent.
What I really want, is for the View to scale to the same height as the Image like this:
How can this be achieved?
Note: I do not know the size of the Image..

Please replace the code and you are good to go.
<?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">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:ignore="MissingConstraints">
<ImageView
android:id="#+id/imageView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:srcCompat="#tools:sample/avatars[1]" />
<View
android:id="#+id/MyView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/imageView"
android:background="#A4D38D14" />
</RelativeLayout>
</android.support.constraint.ConstraintLayout>
The key is to specify android:layout_alignBottom on the View and change the frame layout to relative layout

If I understand your question correctly, you may also try 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">
<ImageView
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:id="#+id/imageView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:srcCompat="#tools:sample/avatars[1]" />
<!-- This is the element of interest.
View is actually a custom element, but for this example, View has same behavior -->
<View
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/imageView"
app:layout_constraintBottom_toBottomOf="parent"
android:id="#+id/MyView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:background="#A4D38D14" />
</android.support.constraint.ConstraintLayout>
I am posting this because as far as I am concerned ConstraintLayout is designed to use a single layout for the entire design,

I also faced a problem like you and figure out that the problem is generated for the <View> item. I fixed the problem by replacing the <View> with <Linearlayout>. Maybe <View> had a special characteristic that's why it is being overflown. My code snippet is -
<FrameLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<!-- This is the view intended to be the overlay-->
<LinearLayout
android:id="#+id/ll_overlay"
android:background="#color/colorAccent"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
</LinearLayout>
</FrameLayout>

ScrollView isn't placed below ToolBar

I faced with the following problem: ScrollView in my activity should be placed below ToolBar. Here's the layout of this activity:
<?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=".SongLyricsActivity">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#0000FF"
tools:ignore="MissingConstraints" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintTop_toBottomOf="#id/toolbar"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginTop="16dp">
<TextView
android:id="#+id/lyrics_textview"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</ScrollView>
</android.support.constraint.ConstraintLayout>
But when I run the app, I see this:
I don't understand, why it happens, as I position it below the toolbar, so, what's the matter?

I solved this problem using a marginTop parameter (equals to toolbar height), like this:
<ScrollView
android:id="#+id/activity_show_scroll_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="?attr/actionBarSize"
android:background="#color/transparent_background"
>
This works for my app.

This is happening because your scroll views height is match_parent and not 0dp - so your scroll view will not respect your constraints and will spread all over your screen.
Please notice that you are using tools:ignore="MissingConstraints" and the tool attribute will only affect the preview so you will see your layout in a different way from the preview.
In addition, you were missing some constraint - app:layout_constraintTop_toTopOf="parent"
Now with that constraint, it should work:
<?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:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#0000FF"
app:layout_constraintTop_toTopOf="parent"
tools:layout_editor_absoluteX="0dp" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintTop_toBottomOf="#id/toolbar"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginTop="16dp">
<TextView
android:id="#+id/lyrics_textview"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</ScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>

you might try:
<LinearLayout>
vertical
<RelativeLayout>
<Toolbar>
someID
parent top
parent left
<Scrollview>
below someID
parent left

Stop empty ConstraintLayout from maximum stretching

When I remove all views from my Constraint layout, I want it to have 0dp height(like wrap_content as it sounds) but it stretches as much as possible.
Is there documented way to do that? I mean besides setting maxHeight to 0 or hiding it.
I've tried app:layout_constrainedHeight="true" with "wrap_content" but it doesnt work.
<?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.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constrainedHeight="true"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</android.support.constraint.ConstraintLayout>

I was unable to find a proper solution.
The simplest workaround I came up with is to add an extra view with height=0 and never remove it:
<?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">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#android:color/holo_red_dark"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<FrameLayout
android:id="#+id/somethingWithNoHeight"
android:layout_width="match_parent"
android:layout_height="0dp" />
<!--<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Lorem ipsum" />-->
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>
I believe you should fill a bug to be sure that developers know about such a problem

Align FrameLayout inside ConstraintLayout to bottom

I want a layout above recycler view at the bottom of the screen,(like a frame) so that even when that layout is visible I can still scroll recycler view behind it. So I want to align the frame layout at the bottom of the screen and make it visible and invisible as per requirement. Here is my code.
<?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.protossoft.root.aesencryption.MainActivity">
<ListView
android:layout_width="match_parent"
android:id="#+id/listView"
android:layout_height="match_parent">
</ListView>
<!-- <RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">-->
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:layout_editor_absoluteX="0dp"
tools:layout_editor_absoluteY="443dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:gravity="center"
android:orientation="horizontal">
<ImageView
android:id="#+id/deviceNumberImage"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="0.2"
android:src="#android:drawable/btn_default" />
<TextView
android:id="#+id/deviceNumber"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="0.8"
android:text="990000862471854" />
</LinearLayout>
</FrameLayout>
<!-- </RelativeLayout>-->
I don't have too much of idea about constraint layout, but when I am moving the view at the bottom from the editor, it is using property like
tools:layout_editor_absoluteX="0dp"
tools:layout_editor_absoluteY="443dp"
I want to achieve the same with some property like align_parentBottom. But none of the properties is available for use. What do I need to do so that the frame layout is visible at the bottom and on the top of recycler view at the same time?
Thanks :)

I want to achieve the same with some property like align_parentBottom.
You should use app:layout_constraintBottom_toBottomOf="parent" attribute.
Here's the setup that you need:
<?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">
<FrameLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent">
...
</FrameLayout>
</android.support.constraint.ConstraintLayout>