Is concatenation of resource strings/string concatenation, possible in layout file?

Question

I have resource strings :

<string name="address">Address</string>
<string name="city">City</string>
<string name="country">Country</string>
<string name="pincode">Pincode</string>  

In my application, at few places I am using these strings alone and at few places I am succeeding them by a colon.
I don't what to create another four resource strings :

<string name="address_with_colon">Address: </string>
<string name="city_with_colon">City: </string>
<string name="country_with_colon">Country: </string>
<string name="pincode_with_colon">Pincode: </string>  

Now to achieve this, I have to concatenate my resource strings with colon. I know this is very easy though java code which I can write in my activity class. But what I want is to do the concatenation in my layout file.
Question : Is string concatenation possible in layout file?
This is where I have to perform the concatenation:

android:text="concatenation_if_possible"

Answer 1

Using XML entities it's possible to use the same string multiple places within an XML file:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE resources [
  <!ENTITY appname "MrQuery">
  <!ENTITY author "Oded">
]>

<resources>
    <string name="app_name">&appname;</string>
    <string name="description">The &appname; app was created by &author;</string>
</resources>

I used this answer: dynamic String using String.xml?

Answer 2

Question : Is string concatenation possible in layout file?

Nope as far as I know.

One solution is to use what @DIVA has answered before.

Another possible solution is to create a custom view that extends TextView (or the view you want to achieve this) and create a custom attribute custom:concatenate which receives a string reference and perform the concatenation automatically. IMHO I think this is the most clean approach.

In code will look as this:

<com.whatever.ConcatenateTextView
    android:text="@string/whatever"
    custom:concatenate="@string/second_string"/>

Or… you can use the power of Drawables creating a custom TextDrawable (which is explained very well by @Devunwired in this post and the concrete implementation of it in Github).

Copying what @Devunwired has said in his post about it:

With this class, text can now be part of the Drawable world, meaning it can not only be set alone in places where you would normally put an image, it can also be placed together with other Drawables in containers like StateListDrawable or animated with the likes of TransitionDrawable and ClipDrawable. In many cases, we can use this to do a job that would otherwise require multiple views or compound controls just to achieve a given visual effect; thus it can reduce overhead in your view hierarchy.

This combined with your custom TextView as I explained before (or whatever view you want to use) gives you a very powerful option. Again copying the example that @Devunwired wrote in his post:

ImageView mImageOne;
TextDrawable d = new TextDrawable(this);
d.setText("SAMPLE TEXT\nLINE TWO");
d.setTextAlign(Layout.Alignment.ALIGN_CENTER);

mImageOne.setImageDrawable(d);

If you need more help please let me know in the comments and I'll gladly update the answer!

Answer 3

You can so something like this :

<string name="meatShootingMessage">You shot %1$d pounds of meat!</string>

String strMeatMsg = String.format(strMeatFormat, ":");

textview.setText(strMeatMsg);

Answer 4

No, you cannot concatenate several string resources into a single string when directly referencing those strings from a layout file.

XML layout files are simply a template of instructions for Android to build a user interface, and you should consider them as a cleaner and more organized way to generate your UI than using a Java class that manually creates and positions views in a layout. That being said, there are limitations to what you can do with a layout file, and one of them is being able to reference a single string resource from every view, meaning that you can't do anything more complex than that, including concatenating several strings into one.

Answer 5

You can do so using this plugin I've created: https://github.com/LikeTheSalad/android-stem It will concat all of the strings you'd like to and will generate at build time a final XML string that you can reference anywhere as with any other manually string you've added.

For your case, you can do the following:

<string name="address">Address</string>
<string name="city">City</string>
<string name="country">Country</string>
<string name="pincode">Pincode</string> 
<string name="address_with_colon">${address}: </string>
<string name="city_with_colon">${city}: </string>
<string name="country_with_colon">${country}: </string>
<string name="pincode_with_colon">${pincode}: </string> 

And then the tool will generate:

<!-- Auto generated during compilation -->
<string name="address_with_colon">Address: </string>
<string name="city_with_colon">City: </string>
<string name="country_with_colon">Country: </string>
<string name="pincode_with_colon">Pincode: </string> 

And anytime you decide to change either your template or values strings, the plugin will keep the generated strings updated. More info on the repo's page.