Develop Reference

fitsSystemWindows not working in Custom Layout within NavigationView

I have a custom View within the NavigationView. The problem is no matter in what combination, fitsSystemWindows is not working within the NavigationView. and the top item in the drawer always stays behind the transcludent statusbar.
main_layout
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:openDrawer="start">
<include
layout="#layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:background="#color/colorPrimaryBottomBar"
android:fitsSystemWindows="true">
<include layout="#layout/navigation_main_drawer" />
</android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>
navigation_main_drawer
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:fillViewport="true"
android:fitsSystemWindows="true"
android:paddingBottom="#dimen/default_margin">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="#dimen/default_margin"
android:fitsSystemWindows="true"
android:orientation="vertical">
<LinearLayout
...
</LinearLayout>
<View
... />
<LinearLayout
...
</LinearLayout>
<View
... />
<LinearLayout
...
</LinearLayout>
<View
... />
</LinearLayout>
</ScrollView>
</android.support.design.widget.CoordinatorLayout>

So, if I've understood correctly, you want your custom view to get the necessary padding so that its contents are not clipped by the status bar right?
If that's the case then you need to set
android:fitsSystemWindows="true"
in your root DrawerLayout, and then set
android:fitsSystemWindows="false"
in your NavigationView component. Note that's false, not true :)
REASONING:
The new NavigationView component designed by Google uses the 'fitsSystemWindows' property to customize how its content relates to the status bar. Note that "customize" here is the key word, because the hardcoded behaviour for this particular component is that its contents should overlap the status bar and reach the top of the screen, while the status bar itself should be transparent to allow the drawer's content to be seen through it. This is specified as part of the new Material Design, as can be seen in https://material.io/guidelines/patterns/navigation-drawer.html.
So, the only way to disable this behaviour is to tell the NavigationView to not signal the fitsSystemWindow property, and only set this in the root DrawerLayout that contains all other views, which will do what you would expect and pad all its children views appropriately.
Note that this reasoning is confirmed also by this comment from Android developer Ian Lake in a blog post talking about this specific property.
P.S.
I would also remove all mentions to the 'fitsSystemWindows' property in all the child elements in your navigation_main_drawer XML, just in case, although it probably does have no effect whatsoever as it is..

Can't make Floating Action Button "float"

First things first, I've checked that answer: How to add shadow to the FAB provided with the android support design library?
But even adding the app:borderWidth="0dp" or elevation="6dp" it didn't work. I have checked this answer: https://stackoverflow.com/a/30752754/1121139 it says as bigger my elevation, bigger is the shadow, and here goes the funny thing, at the preview screen it shows the shadow, but when runs at smartphone I got no shadow.
Here goes an screenshot from smartphone:
and here goes and screenshot from preview screen at android studio:
My layout code:
<RelativeLayout 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"
android:orientation="vertical"
tools:context="amaz1ngc0de.com.br.materialdesign.MainActivity">
<include android:id="#+id/app_bar" layout="#layout/toolbar_app_bar"/>
<android.support.v7.widget.RecyclerView
android:id="#+id/rv_test_fab"
android:layout_below="#id/app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</android.support.v7.widget.RecyclerView>
<android.support.design.widget.FloatingActionButton
android:layout_margin="16dp"
android:layout_alignParentRight="true"
android:layout_alignParentBottom="true"
android:src="#drawable/ic_add_white_24dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:elevation="140dp"
app:borderWidth="0dp"
app:pressedTranslationZ="12dp"
android:clickable="true"/>

Try wrapping your layout inside a CoordinatorLayout and put the FAB at the same level, instead of a RelativeLayout, example:
<!-- main_layout.xml -->
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
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"
android:animateLayoutChanges="true"
android:fitsSystemWindows="true"
tools:context=".activity.MainActivity">
<include layout="#layout/toolbar_app_bar" />
<android.support.v7.widget.RecyclerView
android:id="#+id/rv_test_fab"
android:layout_below="#id/app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<android.support.design.widget.FloatingActionButton
... />
</android.support.design.widget.CoordinatorLayout>
Edit:
This widget is from the design library, you should have it added in your app's build.gradle file:
compile 'com.android.support:design:24.0.0'

OK so I have tried around a bit and it seems shadowing with elevation doesn't work as you imagined. This code gives quite a shadow:
<android.support.design.widget.FloatingActionButton
android:id="#+id/name_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="15dp"
android:src="#drawable/ic_add"
app:elevation="20dp"/>
But if I set elevation to 200, the shadow disappears. So there is only a range at which the shadow is working.
Maybe you can understand it as an object, casting a shadow onto an underlaying object. The higher the elevation, the greater is the distance between the two objects and the less shadow is cast...

Scroll second child in AppBarLayout

I'm trying to obtain this effect where if the user scroll a RecyclerView a certain layout scroll up together with the recycler and disappear behind a Toolbar.
A similar behavior could be obtained using the CoordinatorLayout, this would be possible by setting
app:layout_behavior="#string/appbar_scrolling_view_behavior"
on the said Recycler, and doing
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_scrollFlags="scroll|enterAlways"/>
</android.support.design.widget.AppBarLayout>
Also, If I put a second child inside the AppBarLayout, and set app:layout_scrollFlags to it, the effect obtained is the same, with both layout scrolling together with the Recycler.
What I'm trying to achieve is to keep the first child (The toolbar) fixed in position, and let the second child (a LinearLayout) to scroll and hide behind the toolbar. Unfortunately I couldn't get to this behavior.
Is it possible without using 3rd part library?
Thanks in advance and sorry for my english.

Finally I figured out a way to achieve this behavior, by including the CoordinatorLayout in an LinearLayout and making the second child(LinearLayout) become the first, by moving the Toolbar to the extrnal(root) level
Hierarchy before:
<CoordinatorLayout>
<AppBarLayout>
<ToolBar>
<LinerarLayout>
Hierarchy after:
<LinearLayout>
<ToolBar>
<CoordinatorLayout>
<AppBarLayout>
<LinearLayout>
An exmaple:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
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"
android:orientation="vertical">
<androidx.appcompat.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="48dp" />
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="16dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/colorSecondaryLight"
android:orientation="vertical"
app:layout_scrollFlags="scroll"/>
</com.google.android.material.appbar.AppBarLayout>
.
.
.
.
</androidx.coordinatorlayout.widget.CoordinatorLayout>
</LinearLayout>
Hope that helps!

Android: visibility:gone element is shortly visible

Hy,
I have the problem that a FloatingActionButton with visibility set to GONE shows up very short when opening the activity and then disappears as it should.
The button is used at a later point, that's why it must be invisible. At the moment though if somebody is fast enough (mainly on older devices/android versions), he can click the button before he should be allowed to.
My layout is pretty much the same as it was created by android studio, only that I set the visibility to gone:
<android.support.design.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" android:fitsSystemWindows="true"
tools:context="com.fallenritemonk.ludus.game.GameActivity">
<android.support.design.widget.AppBarLayout android:layout_height="wrap_content"
android:layout_width="match_parent" android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.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" />
</android.support.design.widget.AppBarLayout>
<include layout="#layout/content_game" />
<android.support.design.widget.FloatingActionButton
android:id="#+id/add_fields_fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="#dimen/fab_margin"
android:src="#drawable/ic_add"
android:visibility="gone" />
</android.support.design.widget.CoordinatorLayout>
content_game.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="com.fallenritemonk.ludus.game.GameActivity">
<GridView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/fieldGrid"
android:numColumns="9"
android:verticalSpacing="5dp"
android:horizontalSpacing="5dp" />
</RelativeLayout>
I have no clue where the problem could be. I tried also setting it INVISIBLE instead of GONE. Since I cannot determine if the user was fast enough to press the button before he should have been able to, the only possibility to prevent him from doing so is to remove this "flashing up of the FAB"-bug.
If any more information needed feel free to ask!!!
Thanks for your help

Just add fab.hide() to your onCreate() method (or onCreateView() if using Fragment). You can remove visibility tag from xml as it will no longer be needed. If you want to show your FAB, use fab.show();

Have no reputation enough to comment, so I answer here
Try to place tag android.support.design.widget.FloatingActionButton before include. If it does not help, please, provide content of content_game

Try disabling the anchor id and after that set the visibility. It should work.
Try the following:
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
CoordinatorLayout.LayoutParams param = (CoordinatorLayout.LayoutParams) fab.getLayoutParams();
param.setBehavior(null);
param.setAnchorId(View.NO_ID);
fab.setLayoutParams(param);
fab.setVisibility(View.GONE);
// TO show again
param.setBehavior(new FloatingActionButton.Behavior());
param.setAnchorId(R.id.appbar);
fab.setVisibility(View.VISIBLE);

The problem seems to have been solved by simply updating the android support design library. I now have updated it from 23.0.1 to 23.1.1!

Android fragment getting hidden under the action bar

Got a weird problem. Contents of the fragment getting hidden under the action bar. Its a pretty basic drawer layout and a fragment.
New to android and don't know if this is how it is.
I used margin just to pull this down, as you can see below. But this doesn't sound correct to me... please throw some light where am I going wrong. Thanks in Advance.

It is the normal and expected behaviour if you set FEATURE_ACTION_BAR_OVERLAY (android:windowActionBarOverlay) . Here the documentation

Add an attribute
app:layout_behavior="#string/appbar_scrolling_view_behavior"
to your parent view of your fragment.

Another possible solution for many who see this question is to change the parent layout of the toolbar to LinearLayout (likely with a vertical orientation), as this type of layout does not allow its children to overlap.
For example, this layout in activity_main.xml will result in the fragment being below the toolbar, rather than behind it:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical">
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/app_bar"
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.AppBarLayout>
<FrameLayout
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.fragment.app.FragmentContainerView
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:navGraph="#navigation/nav_graph"/>
</FrameLayout>
</LinearLayout>

Setting top margin of the fragment's layout to height of AcionBar worked, at last!!
android:layout_marginTop="?attr/actionBarSize"
Don't know if this is a better solution but for me this is the only working solution.