Develop Reference

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.

Centering a Linear Layout Horizontal and Vertical

Im running into a speed bump in my android App. I want to center my Linear Layout in the center of the screen (Horisontally only) and I want to center another element only vertically. I haven't seen an easy apparent way to do this in the program.
http://i.stack.imgur.com/gfMBD.png
I want the grey Box to be centered horisontally in the app

I'm not sure, how your layouts are now, but I'd do something like this:
Vertical Linearlayout
RelativeLayout, centered horizontally
RelativeLayout, set to match parent
RelativeLayout, centered vertically

Use RelativeLayout as a root ViewGroup, and then just add android:layout_centerHorizontal="true" to your first LinearLayout, and android:layout_centerVertical="true" to your second one.

Button not centering horizontally

I just started Android development and I'm having trouble figuring out why my text alignment inside my button isn't horizontally centered. It is vertically centered.
I've tried gravity, some padding, center, and text alignment center with no luck. I am using a RelativeLayout with an EditText and a TextView above. When I take the other views out of the activity, there is also no change.
I can get it to center with gravity center_vertical and some padding left, but this method seems inappropriate.
Here is a view of the button before update:
Update: Tested on my ADV for android:gravity="center_vertical|center_horizontal" and it ended up working fine. Seems to be a bug with the Graphic Layout view in Eclipse that is mis-aligning the inner context of the Button view. Here's it working on my AVD:

Set the gravity of the button as android:gravity = "center" or android:gravity = "center_vertical|center_horizontal" .

try layout_gravity="center" or gravity="center" instead. I always forget which one : P

android:gravity = "center"
will align the text inside the button both horizontally and vertically.
android:layout_gravity is different from android_gravity.
Refer for a detailed answer:
Gravity and layout_gravity on Android

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"

How to overlay text on the android map view

I have an application to show the MapView having both height and width fill_parent. I need to overlay some text on the top part of the Map View. How to do this?. The background of text should be transparent. Also the text has the property of marquee. Is it possible to do this?

Use a RelativeLayout as the root container of you layout and add the MapView and a TextView to it (below the MapView in the layout xml file). Use the TextView to display the text which should be displayed above the map. Now you can use the attributes starting withlayout_ to place the TextView where you want it.
As far as I know, the marquee effect only works when the TextView is focused and its text value is too long to fit in the whole TextView.
The TextView's background should be transparent by default.

Create a RelativeLayout as the container of your Mapview and a TextView
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<MapView .../>
<TextView /> </RelativeLayout>
You can display the TextView where you want with the RelativeLayout child attributes, for example on the textView : layout_alignParentBottom="true"

Otherwise just use an itermized overlay to put the text in.