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Android XML layout set attributes of children?

This is a quick, probably yes/no question, but I'm trying to pretty up my xml and I'm wondering if there is a way to have a parent layout override the children's layout_width property? that way I can omit layout_width from every child node, for fewer lines of code?

Short: No.
For layout width is requeired property.

Autosizing TextView in ConstraintLayout

I have a chain in a ConstraintLayout which consists in a TextView, an ImageView and another TextView (doesn't need autosizing). I'd like them three to be vertically centered in the parent container (i.e. same distance to left/right).
I want the TextView to autosize so the text doesn't overflow. I can't use autosize with a layout_width set to wrap_content (nothing happens and the text doesn't resize). I can't set a fixed layout_width either since the extra space when the text isn't very long throws off the alignment.
Is there anyway to do this via XML or should I implement my own autosizing behavior?
This is a picture of what I'm trying to achieve (a center-aligned chain):

For TextView Auto-sizing, use android:layout_width="0dp".
But make sure you apply the ViewComponents Left/Start and Right/End Constraints.
This trick is basically used instead of android:layout_width="fill_parent" in ConstraintLayout.
Using this, you'll achieve Auto-sizing and it will consume only the space falling under the specified constraints and no over-lapping and no spilling-out.

Complext "button" (LinearLayout with child views) with background drawable - on children click doesn't reflect the "state_pressed"

I have a LinearLayout that has 2 children: a ImageView aligned left and a TextView aligned right.
I've set the background of the LinearLayout to be a #drawable XML resource that has two <item> tags. One of them has android:state_pressed="true". Also, the LinearLayout has android:clickable="true".
When the LinearLayout is clicked it correctly changes its background to the android:state_pressed style, but clicking on one of its children doesn't propagate the click action up to the LinearLayout.
Is there a way to easily achieve a click state on the parent view when a child view is clicked?

Dont use Both as it will give Exception
Use this to your parent
android:addStatesFromChildren="true"
Or add in your child views
`android:duplicateParentState="true"`
Hope it helps

not sure if it works for your specific implementation, but a very easy way of achieving this "complex" button is by making a normal button and using android:drawableLeft or android:drawableRight or android:drawableTop or android:drawableBottom and android:drawablePaddig to achieve the same visual result in just one view.
for example:
<LinearLayout orientation=vertical>
<ImageView/>
<TextView/>
</LinearLayout>
is pretty much the same as
<Button
drawableLeft="#drawable/..."
text="..."
/>
that way your whole layout is simpler and the pressed states works out-of-the-box.

Consider using a single TextView and using the android:drawableLeft or android:drawableRight attribute to show your image. It's better design and more performant than a LinearLayout with two children.
If that won't work for you, try adding android:addStatesFromChildren="true" to the LinearLayout.

How to add TextView at below in a RelativeLayout when there is no space at right?

I've seen many of questions for how to add TextView in a RelativeLayout programatically, but everybody adding it in LinearLayout with orientation vertical. Can any one suggest me or give me a link that how to add multiple TextView in RelativeLayout at right until it has space and then change the line.
I want a layout like this..

May be this works for you !
You can customize chips-edittext-library for your need. Customizing by setting background to transparent, and editable to false.
-> Or you can use any other library which is used for displaying emoticon in EditText and customize it according to your need. Like android-emoticon-edittext-spike

You can use the Flow Layout library that manages the view arrangement itself.
When there is no space left the added View is moved to the next line

How to prevent TextView from resizing its container

Take a look at my layout
http://pastebin.com/6tQVm3Rk
My problem is that the textviews (named header1 to 5) are resizing its containers when a certain amount of letters are written into it, although there is still some space left.
What changes do I have to make that the layout stays in its original state independent from the amount of text located in the headers?

This might be because of this attribute.
android:inputType="textMultiLine"
If you want your textview to have only one line you can use android:singleline="true"

Add the attribute
android:maxLength="2"
to the textview. This way you can limit the number of characters.

I think its better to use Relative layout instead Linear layout in the XML so that objects in Relative layout are easy to manage dynamically, all you need to do is that put all those text views in the Relative layout and set these parameters:
layout align left:
layout align right:
And other solution which is not appropriate is that fix the size of text view then it will not expand.
And please see the Documentation for further details of Relative Layout.

Set the width and heigth of your textview to a fixed amount of dp. This will prevent the textview from streching beyond the width and height you declared. Like this:
android:layout_width="50dp"
android:layout_heigth="50dp"

For me the solution was to use
android:layout_width="0dp"
together with
android:maxLines="1"