Doc: describe Gradle support

Change-Id: I37245ccf143f9a1bc40c3d984e3d8f29cec711e7
Reviewed-by: BogDan Vatra <bogdan@kde.org>

doc/src/android/androiddev.qdoc

@@ -50,8 +50,16 @@
         \li \l{http://www.oracle.com/technetwork/java/javase/downloads/index.html}
             {Java SE Development Kit (JDK)} version 6, or later
 
-        \li \l{http://ant.apache.org/bindownload.cgi}{Apache Ant} 1.8.0, or
-            later
+        \li A build tool for building application packages for Android devices:
+
+            \list
+
+                \li \l{http://ant.apache.org/bindownload.cgi}{Apache Ant} 1.8.0,
+                    or later
+
+                \li \l{http://www.gradle.org}{Gradle}
+
+            \endlist
 
         \li A tool chain for building applications for Android devices provided
             by the
@@ -90,6 +98,24 @@
         ./android update sdk
         \endcode
 
+    \section1 Selecting the APK Build Tool
+
+    On Android, applications are distributed in specially structured type of ZIP
+    packages called APK. You can use either Ant or Gradle to build APKs. Using
+    Gradle has the following benefits:
+
+    \list
+
+        \li It is 25 to 50 percent faster than Ant when rebuilding packages.
+
+        \li It is integrated with Android Studio.
+
+        \li It supports easily adding Android Extras libraries, such as
+            Google Play services or Android extension files (.obb) to your
+            project.
+
+    \endlist
+
     \section1 Setting Up the Development Environment
 
     You must download and install the latest Android NDK and SDK, and update the
@@ -116,6 +142,18 @@
             check box to allow \QC to create the kits for you. \QC displays a
             warning if it cannot find a suitable Qt version.
 
+        \li Select the tool to use for building application packages:
+
+            \list
+
+                \li To use Gradle, select the \gui {Use Gradle instead of Ant}
+                    check box.
+
+                \li To use Ant, add the path to the Ant executable in the
+                    \gui {Ant executable} field.
+
+            \endlist
+
         \li Select \gui File > \gui {New File or Project} > \gui Applications >
             \gui {Qt Quick Application} > \gui Choose, and
             follow the instructions of the wizard. For more information, see