I want to concat two strings for a TextView in android, Data Binding Api

concate it with grave accent (`)

android:text="@{`Hello ` + user.firstName}"/>

You can concat it in multiple ways, check it here concat-two-strings-in-textview-using-databinding

This is already answered by @GeorgeMount in comments to one of the solution. Which to me looks like the best solution so far here.

android:text="@{@string/location(user.city,user.state)}"

in your strings.xml

<string name="location">%1$s, %2$s</string>

Many ways to concat strings

1. Using string resource (Most preferable because of localization)

android:text= "@{@string/generic_name(user.name)}"

Just make string resource like this.

<string name="generic_name">Hello %s</string>

2. Hard coded concat

android:text="@{`Hello ` + user.name}"/>

3. Using String's concat method

android:text="@{user.firstName.concat(@string/space).concat(user.lastName)}"

Here space is an html entity which is placed inside strings.xml. Because XML does not accept Html entities or special characters directly. (Link Html Entities)

<string name="space">\u0020</string>

4. Using String.format()

android:text= "@{String.format(@string/hello, user.name)}"

you have to import String class in layout in this type.

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <import type="String" />
    </data>
    <TextView
        android:text= "@{String.format(@string/hello, user.name)}"
        ... >
    </TextView>
</layout>

5. Another method

android:text="@{@string/generic_name(user.firstName,user.lastName)}"

In this case put a string resource in strings.xml

<string name="generic_name">%1$s, %2$s</string>

There can be many other ways, choose one you need.