Develop Reference

FrameLayout with layout_weight is considered useless

Consider the following layout:
<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/black"
>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="2"
/>
<TextView
android:id="#+id/primary_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textColor="#color/white"
android:textSize="24sp"
tools:text="Primary!"
/>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
/>
<TextView
android:id="#+id/secondary_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textColor="#color/white"
android:textSize="24sp"
tools:text="Secondary!"
/>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="3"
/>
</LinearLayout>
See the screenshot below for the result. The layout works fine, but Android Studio warns me that the FrameLayouts are considered useless and should be removed. However, they're not useless. I use layout_weight here. The idea is that the space between and around the two TextViews are relative with weights 2:1:3.
How can I rewrite my layout that results in the same weighted positioning of the views without having to use empty FrameLayouts?

You can get rid of the first two FrameLayout by setting the height of your TextView to 0dp and their weight to the values you set for your FrameLayout.

FrameLayout is a container that is supposed to have children. For a gap, a View is sufficient. I replaced each empty FrameLayouts with:
<View
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
/>
and the linter warning was gone.

How to customize the orientation of individual elements in a custom linear layout in a recyclerView Android Studio?

I'm trying to change the alignment of the row layout elements in a linear RecyclerView this is my code:
<?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"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:layout_width="120dp"
android:layout_height="94dp"
app:srcCompat="#mipmap/ic_launcher_round"
android:id="#+id/taskThumbnailImg"
android:layout_weight="1"
/>
<TextView
android:layout_width="227dp"
android:layout_height="wrap_content"
android:id="#+id/taskCustomerName"
android:layout_weight="1"
android:textSize="30sp"/>
<TextView
android:id="#+id/taskLocation"
android:layout_width="wrap_content"
android:layout_height="56dp"
android:layout_weight="1"/>
</LinearLayout>
Which currently displays Horizontally as:
But this is how I wish to create a layout:
This is neither vertical or horizontal. What do I need to alter to create this layout?
I appreciate the help!

LinearLayout will let you add views either horizontally or vertically. Though you can achive this usig LinearLayout, it's not recomended since more effeciant layouts are exists.
Try to learn different Layouts android uses. Then you'll understand better which will suits you.
I'll suggest simple RelativeLayout or ConstraintLayout for complex cases.

You can use a Linear Layout inside the Linear layout to align the items horizontally. Please add margins and widths for the TextViews as you need.
<?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"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:layout_width="120dp"
android:layout_height="94dp"
app:srcCompat="#mipmap/ic_launcher_round"
android:id="#+id/taskThumbnailImg"
android:layout_margin="5dp"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:text="taskCustomerName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/taskCustomerName"
android:layout_weight="1"
android:textSize="30sp"/>
<TextView
android:text="taskLocation"
android:id="#+id/taskLocation"
android:layout_width="wrap_content"
android:layout_height="56dp"
android:layout_weight="1"/>
</LinearLayout>
</LinearLayout>

Android: recalculate dimension of layout components

I've a linear layout with few compononents, most of them have setted specific dimensions, but 1 is set to 0dp in other to fill the remaining space.
The thing is after inflate the xml layout i programatically add one more component, and the 0dp view doesn't shrink to fit this new component so it makes the layout to appear wrongly.
There are enough space for all components, if i try for example to add the "dinamic" component on the xml (just for test) and inflate it, all will appear well.
How can i force a LinearLayout to re-calculate the views height?
what i get:
here goes the code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
android:id="#+id/mainView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:orientation="vertical"
android:paddingLeft="#dimen/smallMargin"
android:paddingRight="#dimen/smallMargin"
android:visibility="visible">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_margin="5dp"
android:layout_weight="1"
android:scrollbars="vertical" />
<LinearLayout
android:id="#+id/giveawayResult"
android:layout_width="match_parent"
android:layout_height="#dimen/giveawayCardHeight"
android:layout_marginBottom="#dimen/smallMargin"
android:layout_marginTop="#dimen/smallMargin"
android:visibility="invisible">
<RelativeLayout
android:layout_width="160dp"
android:layout_height="#dimen/giveawayCardHeight">
<ImageView
android:id="#+id/raffleThumbnail"
android:layout_width="160dp"
android:layout_height="match_parent"
android:scaleType="centerCrop"
android:src="#drawable/asd" />
<TextView
android:id="#+id/raffleOwner"
android:layout_width="180dp"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:alpha="0.7"
android:background="#color/colorPrimaryDark"
android:gravity="center_horizontal|bottom"
android:text="viajandocomgabi"
android:textColor="#color/cardview_light_background"
android:textSize="16sp" />
</RelativeLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="#dimen/smallMargin"
android:orientation="vertical">
<EditText
android:id="#+id/raffleDate"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:focusable="false"
android:hint="#string/raffle_date_label"
android:inputType="date"
android:longClickable="false"
android:textSize="#dimen/discreteFont" />
<EditText
android:id="#+id/amountToIndicate"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:hint="#string/prompt_friends_to_indicate"
android:inputType="number"
android:lines="1"
android:textSize="#dimen/discreteFont" />
<Space
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="#string/save" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
=========UPDATE==========
To make things clear:
1- the adview is added dynamically
2- the recycleview is 0dp because i want it to fill the left space
3- after inflating the layout the recycleview is dimentioned by android api, after that i add the adview, and IT DOESN'T GET RESIZED, so the result is what you see on the photo
i need to know how to force android to redimensionate recycleview to shrink to fit the space

To refresh the LinearLayout, or any view, you use its invalidate() method.
Edit: If you wish to remeasure the view, call it's requestLayout() method. Don't forget to invalidate it too.
Also, your Admob Banner Ad is breaking their Policy. Banner Ads can't overlap on app content.

CardView goes on top of FrameLayout, but declared first

I have simple FrameLayout with support CardView as first item, and TextView as second, so TextView must be on top of inflated view. This works on pre-Lolipop but on 21+ card takes toppest place in layout, why that's so and how to fix this? Same thing with RelativeLayout.
Layout:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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="wrap_content">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_margin="20dp"
app:cardBackgroundColor="#ff0000"
app:cardUseCompatPadding="false"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:text="i am top view!"
android:gravity="center"
android:layout_gravity="center"
android:textSize="30sp"
android:textAllCaps="true"
android:textColor="#00ff00"
android:background="#0000ff"
/>
</FrameLayout>

In case someone gets here and the solution for setting elevation doesn't work for them (like in my case, where I needed to draw an image above the CardView and having a shadow on it was not acceptable), you can solve the issue by wrapping the CardView inside another FrameLayout. In the example provided, it would look something like this:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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="wrap_content">
<!-- This is the added FrameLayout -->
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_margin="20dp"
app:cardBackgroundColor="#ff0000"
app:cardUseCompatPadding="false"
/>
</FrameLayout>
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:text="i am top view!"
android:gravity="center"
android:layout_gravity="center"
android:textSize="30sp"
android:textAllCaps="true"
android:textColor="#00ff00"
android:background="#0000ff"
/>
</FrameLayout>

I might be joining the discussion a bit late, but if you can afford giving up the CardView's elevation, you can just set the cardElevation property of the CardView in your XML layout to 0dp.
Like so:
app:cardElevation="0dp"

Just add your text view inside the card view, far as I know the z order is undefined inside a frame layout, but last laid out view should be drawn last.
This probably had to do with that card views in lollipop use elevation while they fall back on border drawing code pre lollipop.

This worked for me!
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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="wrap_content">
<!-- Add this layout as parent of CardView -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_margin="20dp"
app:cardBackgroundColor="#ff0000"
app:cardUseCompatPadding="false" />
</LinearLayout>
<!--Close parent layout-->
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:layout_gravity="center"
android:background="#0000ff"
android:gravity="center"
android:text="i am top view!"
android:textAllCaps="true"
android:textColor="#00ff00"
android:textSize="30sp" />
</FrameLayout>

Android ScrollView and buttons at bottom of the screen

I want to implement this: A ScrollView that contains many elements (ImageViews, TextViews, EditTexts etc) and then after the ScrollView some buttons (which are custom ImageViews) that appear always exactly at the bottom of the screen.
If I use the android:fillViewport="true" attribute, then if the elements of the ScrollView are too big to fit in the screen size the buttons get invisible . If I use the android:Weight=1 attribute then the ScrollView gets only 50% of the Screen when the screen is big and it can fit (I want the buttons to take a small percentage, about 10%). If I set the android:Weight to bigger values then the buttons appear very small.
Please help! Maybe it is something simple that I overlooked but I’ve been banging my head for hours!

Just created and tested it. Looks like you want.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="#+id/buttons"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center"
android:layout_alignParentBottom="true">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Custom Button1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Custom Button2"/>
</LinearLayout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#id/buttons">
<!--Scrollable content here-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="test text"
android:textSize="40dp"/>
</LinearLayout>
</ScrollView>
</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ScrollView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hallo Welt"
/>
</LinearLayout>
</ScrollView>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Go next page"
android:layout_alignParentRight="true" />
</RelativeLayout>
</LinearLayout>

This worked for me. Give the scroll view a weight of 1. Put all the other widgets following the scroll view in a layout. The scroll view will grow enough to not block the rest.
Widgets in scroll view and rest at bottom

scrollview cannot fit the screen because you put it on a linear layout, so linear layout fit in the screen,
just try to make scrollview as root elemen on xml layout
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/scrollView1"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:id="#+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<!-- Here you can put some XML stuff and BOOM! your screen fit to scrollview -->
</LinearLayout>
</ScrollView>

If you do not want to use RelativeLayout, it is better to use LinearLayout. This method is better in my opinion.
Just set the layout_weight to one