Develop Reference

How to use with CollapsingLayout with Navigation Advanced Example

I am trying to integrate Collapsing layout with Navigation Advanced example
What I tried?
Added Collapsing bar layout to main_actvity.xml
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<com.google.android.material.appbar.CollapsingToolbarLayout
android:id="#+id/collapsing_toolbar_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"/>
</com.google.android.material.appbar.CollapsingToolbarLayout>
</com.google.android.material.appbar.AppBarLayout>
Modified setupBottomNavigationBar() in MainActivity.kt
private fun setupBottomNavigationBar(){
...
controller.observe(this, Observer { navController ->
mainBinding.collapsingToolbarLayout.setupWithNavController(mainBinding.toolbar, navController)
//setupActionBarWithNavController(navController)
})
...
}
Current issue:
Now I have two ActionBars instead of one. Top one have app name as the title, one below shows nothing initially but when navigated to an sub destination only a grey back arrow is shown, no destination label is shown on the actionbar
Anyone who understand this multiple backstack implementation, please help me to get things work with CollapsingToolbarLayout
Update:
Got rid of one action bar as #Manoj suggested in a comment, Now need to fix not appearing of titles in the actionbar
Update 2:
Although the destination labels(titles) are not shown when navigated to sub destinations, but back button is shown.

if the title is not displayed (and that increasing the appbar layout height "works"), just set the isTitleEnabled of the collapsingToolbarLayout to false.
It should fix the problem

I finally figured out why the toolbar title was not shown reason was I have not set enough height for appbar layout, I was using wrap_content so collapsing toolbar layout was covering the toolbar title. Solution was to set appbar layout height to value larger than 64dp. When I increased the appbar layout height, it looks unusually tall. (Forgive me for my lack of understanding of how collapsing toolbar works)
But this was not my intention, I wanted to enable collapsing toolbar for some specific fragments, I was using single activity concepts as navigation architecture component recommends.
As I read in following answers
Having two toolbars and making one transparent when doing fragment transactions.
Having separate toolbar for each fragment
IMHO Both of these are not good solutions if you are using navigation architecture component, there is no value of using navigation architecture component, if you need to manage fragment transactions or toolbars manually.
So for now I have stop using collapsing toolbar.

Fragment's layout is too high with TabLayout + AppBarLayout

I'm struggled with this for hours looking for solution on google and stackoverflow. Thought that this is some trivial bug in my app but finally made empty project and can reproduce this too. Just run new project and select "Tabbed Activity" with navigation style "Action Bar Tabs (with ViewPager)
Then try to put any widget at the bottom of the fragment's layout. I did this by modify fragment_main.xml and adding:
android:layout_height="match_parent"
android:gravity="bottom"
android:textAlignment="center"
So the whole layout is:
<?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:id="#+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity$PlaceholderFragment">
<TextView
android:id="#+id/section_label"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="#dimen/activity_vertical_margin"
android:gravity="bottom"
android:text="aaaaaaa"
android:textAlignment="center"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="#+id/constraintLayout"
tools:layout_constraintLeft_creator="1"
tools:layout_constraintTop_creator="1" />
</android.support.constraint.ConstraintLayout>
In design mode everything looks fine:
But when you run app:
You will see text only when you swipe action bar to hide it:
So it is impossible to set widget at the bottom of the tab's fragment or even match some list/picture to the height of the parent because bottom edge will be always under navigation bar.
Workaround which I found is here:
ViewPager with Toolbar and TabLayout has wrong height
First one is to put AppBarLayout and ViewPager between LinearLayout but then I lose hidding action bar functionality when scrolling ViewPager's content. Second one is add android:paddingBottom="?attr/actionBarSize" in ViewPager but then there is a gap when I hide action bar. Seriously there is no solution for this?

I think this is an expected behavior since the ActionBar gets hidden when scrolling up. In the design mode the text can be shown because it doesn't display the TabLayout. However, when you launch the app, it will inflate the TabLayout and the fragment will go below it. So it's not like the fragment is getting expanded or giving you wrong height.
Imagine putting an ImageView that has a matching height of the visible field (from below the TabLayout to right above the navigation menu). When you hide action bar from there, it will have a gap on the bottom since there's no content to fill up the space of hidden action bar, unless you stretch the ImageView as you scroll up, which will result in wired stretched image :/
One possible solution I can think of is, if you want to add a view on the bottom of the fragment, I will set the actionbar padding to the view and when I scroll the screen, I will adjust the padding depends on the scroll offset so that I can always be on the bottom.

Display the icon at the right of the text in navigation view

sorry for my bad English.
I have a navigation drawer in some activities, I want the icon of each navigation view item to be placed to the right of that item's text and the whole item get right gravity.
Because I only used Persian in my app, I can not use "supportsRtl" in my code, if I use, it will look weird when I set device language to any rtl languages.
I think probably I can fix this with setting custom layout for navigation view, but I'm looking for a simpler way. this is my NavigationView XML code:
<android.support.design.widget.NavigationView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:menu="#menu/menu"
android:layout_gravity="end" />
Edited :
layoutDirection is a good answer but i used drawerLayout.openDrawer(GravityCompat.START);
for opening navigation drawer. now if device language be an rtl language this make app crash.

Make supportsRtl true and set the layout dirction to RTL on navigation View and LTR in other layouts

Just add android:layoutDirection="rtl" to your NavigationView, like this:
<android.support.design.widget.NavigationView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:menu="#menu/menu"
android:layoutDirection="rtl"
android:layout_gravity="end" />

New Bottom Layout from Google

First of all, I am sorry to ask a question like this but after I downloaded latest Google IO app,
I am just loving the bottom Layout as shown in the following
screenshot
Being new to android development, I have no clue where to start, Any idea how to achieve this bottom Layout with circle star in XML? Does anyone know what this design is called?

You can use the new Material Components for Android and the BottomAppBar component.
Use something like:
<com.google.android.material.bottomappbar.BottomAppBar
android:id="#+id/bar"
android:layout_gravity="bottom"
app:fabCradleMargin="8dp"
app:fabCradleRoundedCornerRadius="8dp"
app:fabCradleVerticalOffset="0dp"
... />
<com.google.android.material.floatingactionbutton.FloatingActionButton
app:layout_anchor="#id/bar"
../>
You have to use these attributes:
fabCradleMargin attribute.
It increases or decreases the distance between the FloatingActionButton and the BottomAppBar
fabCradleRoundedCornerRadius attribute. It specifies the roundness of the corner around the cutout
OLD SUPPORT LIBRARY
With the Support Library 28.0.0, the Design Library contains the BottomAppBar.
You can use
<android.support.design.bottomappbar.BottomAppBar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:backgroundTint="#color/colorPrimary"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
You can customize the component using these attributes:
app:fabAlignmentMode: Declares the position of the FAB which has been attached to the bottom app bar. This can be either end or center
app:fabCradleVerticalOffset: Declares the vertical offset to be used for the attached fab. By default this is 0dp.
app:backgroundTint: Used to apply a tint to the background of the view.
Also you you can attach a fab by using app:layout_anchor on the FAB component which you wish to attach, using the ID of the bottom app bar.

I believe it's the BottomAppBar, coming in support library 28.0.0. You can read more here: https://medium.com/#lupajz/the-place-for-bottomappbar-31e0db8f70b1

App bars: bottom
Bottom app bars provide access to a bottom navigation drawer and up to four actions, including the floating action button.
Bottom app bars can contain actions that apply to the context of the current screen. They include a navigation menu control on the far left and a floating action button (when one is present). If included in a bottom app bar, an overflow menu control is placed at the end of other actions.
Informações enter link description here
<android.support.design.widget.FloatingActionButton
android:id="#+id/FloatingActionButtonAddEmp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center_horizontal"
app:srcCompat="#drawable/ic_save_black_24px"
app:layout_anchor="#+id/bottom_appbar"/>
<android.support.design.bottomappbar.BottomAppBar
android:id="#+id/bottom_appbar"
android:elevation="4dp"
style="#style/Widget.MaterialComponents.BottomAppBar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:fabAttached="true"
app:backgroundTint="#color/io15_grey"/>

Navigation Drawer Notification Icon without Actionbar

In my application I do not want to use the actionbar or toolbar as my app is fairly simplistic and having one of those two would clutter my application. I know when using an actionbar with a navigation drawer there is an icon on the top left to show the drawer exists; however, I want a small notification icon in the middle of the screen to show that the drawer exists. Perhaps a clear arrow? Is this possible? I can not find any documentation on how I would approach doing this. Thank you.
Edit:
I do not want to use ANY type of action bar

Update 2
You can wrap your indicator in a RelativeLayout.
<RelativeLayout android:layout_width="match_parent"
android:layout_width="match_parent"/>
<MyIndicator
android:id="#+id/indicator"
android:layout_width="match_parent"
android:layout_width="match_parent"
android:layout_centerVertical="true"
android:layout_alignParentStart="true"/>
<OtherView android:layout_width="match_parent"
android:layout_width="match_parent"/>
</RelativeLayout>
Update
Use FloatingActionButton from design library.
If you use a toolbar you can set a custom icon. Here is another post doing something like that: Custom icon in Android toolbar

You can use custom action bar in your app that can be customized according to your need.
Refer this link Custom Action Bar