Develop Reference

Make scrollview works with a map

I have an app which needs an ScrollView and a Google maps map, my problem is that the scrollview goes over the map. so when I want to move the map horizontally everything works, but when I want to move the map vertically, instead of that it moves my scroll view here is the XML(ignore the "is gone" parts, I just put the map visible with a button in my code)
<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout
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=".CreateActivity"
android:id="#+id/drawerLayout"
tools:ignore="ExtraText">
//Inicio primera parte(navigation view cerrado)
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="30dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:ignore="ExtraText,SpeakableTextPresentCheck">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_marginHorizontal="15dp">
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginHorizontal="50dp"
android:layout_marginBottom="20dp"
android:background="#drawable/round_button"
android:onClick="createUbicacion"
android:text="#string/CreateUbication"
android:textColor="#FFFFFF"/>
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/MapLayout"
android:layout_width="match_parent"
android:layout_height="300dp"
android:visibility="gone" >
<fragment
android:layout_width="match_parent"
android:layout_height="300dp"
android:id="#+id/map"
tools:context=".MapsActivity"
android:name="com.google.android.gms.maps.SupportMapFragment"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>
</ScrollView>
PD:I need the scrollView because there are much more elements, I had removed them here to simplify it

Zoom photo inside viewpager2

I tried to use PhotoِDarweeView inside ViewPager2. When I want to zoom in on the photo horizontally, it does not zoom in and instead the ViewPager2 swipes.
activity_media_view:
<?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/root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/black"
tools:context=".ui.MediaTopicActivity">
<androidx.viewpager2.widget.ViewPager2
android:id="#+id/viewPager"
android:layout_width="0dp"
android:layout_height="match_parent"
app:layout_constraintBottom_toTopOf="#+id/title"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/header"
tools:background="#drawable/one"
tools:layout_height="300dp" />
<!-- other views -->
</androidx.constraintlayout.widget.ConstraintLayout>
fragment_photo:
<?xml version="1.0" encoding="utf-8"?>
<me.relex.photodraweeview.PhotoDraweeView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" />

I resolved this by enabling nestedScrolling for my viewPager2
<androidx.viewpager2.widget.ViewPager2
android:id="#+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:nestedScrollingEnabled="true" />

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>

ListView in ConstraintLayout not displaying

Been knocking my head for hours trying to figure out what am doing wrong with this. I have a ListView in a ConstraintLayout that isn't being displayed. I am just getting accustomed to using ConstraintLayout so u'll forgive me for any silly mistakes. These are my layout files
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
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">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/AppTheme.PopupOverlay" />
</com.google.android.material.appbar.AppBarLayout>
<include layout="#layout/content_main" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
content_main.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"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<ListView
android:id="#+id/noteList"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
The ListView in the above file doesn't display at all but when I substitute the ListView with a RecyclerView, the list is displayed.
<?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"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/noteList"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
What am I doing wrong with the ListView that makes it not work and yet RecyclerView works fine?

If you want to preview your ListView in design mode, you'll have to use the tools namespace.
Add something like this to your XML file;
tools:listitem="#android:layout/simple_list_item_1"
Then add the tools namespace to the top of your XML file like so;
xmlns:tools="http://schemas.android.com/tools"
So, your file should look like this;
<?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"
xmlns:tools="http://schemas.android.com/tools"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<ListView
android:id="#+id/noteList"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
tools:listitem="#android:layout/simple_list_item_1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
That way you'll be able to preview your list view.

How to add a button and overlay it on my Google map fragment

So I have myself a GoogleMap using my API key. I'm able to find my location, but when opened the app does not have any buttons. If I try to click and drag any buttons in via the android design layout, it doesn't allow this.
This is what my activity_maps.xml looks like:
<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MapsActivity" />
When looking at the android phone view beside it, it just says and I am unsure how to add a button on top of this map, or even below it if possible.
I am aware of ConstraintLayout and FrameLayout, but when adding additional code I just get 'multiple roots error'and have been unable to achieve what I am looking for.
Could anyone help me out?

Here is example with constraint layout
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".MapsActivity">
<fragment
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
/>
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:layout_margin="16dp"
/>
</android.support.constraint.ConstraintLayout>

Maybe a simpler solution is to set an overlay in front of your map using FrameLayoutor RelativeLayoutand treating them as regular buttons in your activity. You should declare your layers in back to front order, e.g., map before buttons, Try the following layout and see if it works for you
<FrameLayout 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=".MapActivity" >
<fragment xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="#+id/map"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:scrollbars="vertical"
class="com.google.android.gms.maps.SupportMapFragment"/>
<Button
android:id="#+id/btn"
android:layout_width="match_parent"
android:layout_height="48dp"
android:orientation="horizontal"
android:background="#80000000"
android:padding="4dp" >
</FrameLayout>

You have to wrap your fragment with FrameLayout, LinearLayout, RelativeLayout or ConstraintLayout and then set additional buttons.
Instead of this:
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MapsActivity" />
It should look like this:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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">
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MapsActivity"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentBottom="true"
android:layout_margin="15dp"
tools:text="Button one"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentBottom="true"
android:layout_margin="15dp"
tools:text="Button two"/>
</RelativeLayout>
This is just example with RelativeLayout.