Develop Reference

ConstraintLayout spacing between weighted Views?

I am trying to build an Android UI where I need 7 boxes with the days of the week. In order to do this, I decided to go with a ConstraintLayout in order to be able to auto resize my views on any screen.
I created a chain between all 7 views with the with the "spread_inside" attribute, with worked but since I had my views' widths set to wrap_content, due to the nature of TextViews the views did not have equal widths. So I tried making them have equal widths by setting all of 7 views' widths to 0dp. This works but leaves no space between the views. Is there a way to add some spacing between these 7 views? Or is there another way of achieving the "equal widths" to all 7 views while keeping the auto-resizing ability on any screen? Is this even possible with ConstraintLayout or should I keep using LinearLayout for this kind of things? (as seen in the last screenshot)
I want my views to shrink when the screen is small and to expand up to a level when the screen is big. Please see the screenshots below of how it looks now. I want to add an 8dp padding between each view (on a LinearLayout I achieve this by adding a transparent divider on the layout with 8dp width, as in the last screenshot)
How it should look, achieved using LinearLayout

if you want them to be all the same width you don't even need spread_inside, just set the width to 0dp and then add margins to the views. for example:
<?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">
<View
android:id="#+id/view1"
android:layout_width="0dp"
android:layout_height="50dp"
android:layout_marginRight="4dp"
android:layout_marginLeft="8dp"
android:background="#ffff0000"
app:layout_constraintEnd_toStartOf="#+id/view2"
app:layout_constraintStart_toStartOf="parent"/>
<View
android:id="#+id/view2"
android:layout_width="0dp"
android:layout_height="50dp"
android:layout_marginRight="8dp"
android:layout_marginLeft="4dp"
android:background="#ff00ff00"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/view1"/>
</android.support.constraint.ConstraintLayout>
keep in mind that space between views will be the sum of 2 margins, first and last view will have only 1 margin space, so you need to set them accordingly (like 4dp for margins between views and 8dp for first and last margin)

Have elements equally span entire width / height of their RelativeLayout

I have, say three buttons i would like to list below one another in a layout. Depending on the device, screen size, pixel density, orientation and so on, i would like the buttons to span the entire height of their parent layout. The buttons each have a fixed height (dp), so the spanning is more likely concerning the space between the buttons.
I saw several questions on various forums regarding how a LinearLayout is supposedly a fix for this problem, by nesting a layout for each element, having the layout span. I would very much like to avoid nesting layouts, and I'm using a RelativeLayout as of now, so if there is any way to go about it with this type of layout it will be of great help! :)
Additionally, I would like the top and bottom button to "touch" the parent layout border at the top and bottom, and the last (or rest) button to fill out the rest of the vertical space equally.
Thank you in advance.

I'm not entirely sure what you wish to achieve, but you should be able to do this using a LinearLayout & weights (so you don't have to nest multiple layouts).
If you want the 3 buttons to take up the entire parent of the screen just add a weight to each for example:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="#+id/button_one"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
<Button
android:id="#+id/button_two"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
<Button
android:id="#+id/button_three"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
</LinearLayout>

Try to set to topButton a field in XML:
android:layout_alignTop="true";
Try to set to middleButton a field in XML:
android:layout_centerVertical="true";
Try to set to bottomButton a field in XML:
android:layout_alignBottom="true";

android:layout_height not working for CardView

I am working with CardViews inside a RecyclerView with GridLayoutManager. The problem that I am facing is, the height I specify for the card view inside xml or in java, it doesn't get enforced by the CardView. It seems like the cumulative height of the child views of the CardView becomes the height of the CardView. This behavior considering the fact that it's parent's layout parameters that are enforced on its child views.
What am I missing? Am I doing something wrong?
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="#+id/cardView"
android:layout_width="#dimen/card_view_width"
android:layout_height="0dp"
android:layout_marginBottom="6dp"
android:elevation="10dp"
android:orientation="horizontal"
card_view:cardCornerRadius="2dp"
>
<ImageView
android:layout_width="#dimen/card_view_width"
android:layout_height="10dp"
></ImageView>
</android.support.v7.widget.CardView>
In this case the height of the card view is 0dp but still the layout designer preview & when the app runs on the device, the size of the card is 10dp.
Best Regards

What do you expect to happen, with what you told the program?
You tell the CardVeiw to have a height of 0dp with this:
android:layout_height="0dp"
Then you place an ImageView inside, and tell it to have a height of 10dp.
So of course the CardView makes itself taller to allow the ImageView to fit properly.
If you want the inner elements to match the height of the CardView, set the layout_height of the CardView to whatever you want, like 20dp:
android:layout_height="20dp"
Then have the inner elements match_parent:
android:layout_height="match_parent"

Why are you setting visibility to 0? IF you are trying to hide it, use `visibility = View.GONE'.
ALso, don't use elevation which won't work before L. Insteed, use cardElevation so that it will work before L as well.

Try to set android:layout_height="wrap_content" in your CardView.

Android RelativeLayout and height of wrap_content?

I am trying to make a selection ListActivity, similar to the one used to add shortcuts to the launcher screens. I have rolled my own header and footers, which I would like to be "sticky" at the top and bottom of the view when on screen. In order to do this, I am using a RelativeLayout with the header set to dock to top, footer set to dock to bottom, and the list set to go below the header and above the footer. In terms of the overall layout of the activity, this is rendering as I would expect. The header is sticky to the top, the footer is sticky to the bottom, and the list scrolls in between them.
One odd thing though happened when I switched to the RelativeLayout as my root. Please see the following screenshot:
I want my Activity's height to be wrap_content, so that the form is only as high as the content displayed in it, but once i switched to RelativeLayout, it seems to render the Activity effectively as fill_parent, taking up the whole screen, even though the content doesn't warrant it. Notice that there are not enough list items to fill the screen, which with the fill_parent style, is leaving a bunch of whitespace between the end of the list, and the footer. I was setting my height's via styles - which worked fine with LinearLayout, but seems to be ignored now. So I tried hard-coding the height directly on the RelativeLayout, but it still doesn't work and still renders as fill_parent.
Here is my layout code:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
style="#style/GroupsList"
android:layout_height="wrap_content">
<FrameLayout android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:id="#+id/hdrGroups"
android:layout_alignParentTop="true">
<include layout="#layout/title"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</include>
</FrameLayout>
<FrameLayout style="#style/MyFooter"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:layout_alignParentBottom="true"
android:id="#+id/ftrGroups">
<ImageView style="#style/CloseButton"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:src="#drawable/add"
android:id="#+id/imgGroupsAdd"
android:clickable="true">
</ImageView>
</FrameLayout>
<ListView android:divider="#9f9f9f"
android:id="#+id/android:list"
android:choiceMode="singleChoice"
android:dividerHeight="1dp"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:layout_below="#id/hdrGroups"
android:layout_above="#id/ftrGroups">
</ListView>
<TextView android:text="#string/browser_no_groups"
style="#style/ListedItemB"
android:id="#+id/android:empty"
android:layout_height="wrap_content"
android:layout_above="#id/ftrGroups"
android:layout_below="#id/hdrGroups"
android:layout_width="fill_parent">
</TextView>
</RelativeLayout>
All layout is done via XML, ... I am not doing any layout in code.
How can I get the sticky header and footer while also having the activity as a whole behave in a wrap_content mode for its height? Is there some other way I should be going about this instead of a RelativeLayout?

According to the developer documentation your desired behaviour is not possible for Relative layout ;
"Note that you cannot have a circular dependency between the size of
the RelativeLayout and the position of its children. For example, you
cannot have a RelativeLayout whose height is set to WRAP_CONTENT and a
child set to ALIGN_PARENT_BOTTOM."
RelativeLayout
To solve your problem you could maybe try to use a linear layout, set to wrap_content and set max height via code to screen height.
You can get the screen height as described here : get screen height

I just change my RelativeLayout in FrameLayout and all starts to work

How to wrap content views rather than background drawable?

How can I get a LinearLayout (or any other ViewGroup) to assume the size of it's child views rather than assuming the size of the background image?
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/large_image300x300pix">
<TextView android:id="#+id/TextView01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello world!"/>
</LinearLayout>
The linear layout becomes the same size as the background image.
How can I get my linear layout to assume the same size as the textview?

OK, so this thread is a little old, but I have a solution that someone might someday find useful. I think Android has problems scaling large images down, so the LinearLayout size ends up getting bumped by the background drawable bitmap, and the ImageView ends up forcing up the size of the parent container.
Unless you use a relative layout. You can make the ImageView relative to the position of the LinearLayout, even when the ImageView is behind the layout in the parent. My solution looks something like this:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
xmlns:android="http://schemas.android.com/apk/res/android">
<ImageView
android:src="#drawable/activation_popup"
android:scaleType="fitXY"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_alignTop="#+id/activation_layout"
android:layout_alignBottom="#id/activation_layout"
android:layout_alignLeft="#id/activation_layout"
android:layout_alignRight="#id/activation_layout"
android:contentDescription="#string/act_code_label" />
<LinearLayout
android:id="#id/activation_layout"
android:clipToPadding="true"
android:padding="25dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<!-- LinearLayout wraps a bunch of smallish views here -->
</LinearLayout>
</RelativeLayout>
I tried this on a top of display sizes and OS versions, seems to work great. Note that the padding in the LinearLayout is a trick to make space for a shadow border in the background image graphic. The LinearLayout doesn't need any relative positioning because top left is assumed.

You can create a FrameLayout and put an ImageView and your LinearLayout there. So you'll be able to configure the layout of your background image.

This happens because the Android view calculates its minimum size based on its background drawable size.
Check my answer here in this another post which covers the same problem which will help you to achieve your layout configuration.

If your image lends itself to being converted to a scalable 9-patch image, then doing that would cause the background to scale around the TextView.

I believe the best solution here is to set android:clipToPadding="true". What this does is excludes the padding for the main layout and wraps your layout to its children.