Explain how to identify missing dependencies for Android deployment

When you deploy on Android, the tool will attempt to guess which
plugins you need. This can be confusing to many who are trying
to load e.g. images with formats that require a specific plugin
to load. So we explain in the documentation how you can debug this
and find out what modules to add to your .pro file.

Task-number: QTBUG-34586
Change-Id: Iaa13e0cc4183e3574d1b0d66a1352720c6e45753
Reviewed-by: Venugopal Shivashankar <venugopal.shivashankar@digia.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/doc/src/deployment/deployment.qdoc b/doc/src/deployment/deployment.qdoc
index 3d779a2bf..10f338cc8 100644
--- a/doc/src/deployment/deployment.qdoc
+++ b/doc/src/deployment/deployment.qdoc
@@ -431,6 +431,26 @@
     doing.
     \endlist
 
+    \section1 Dependencies detection
+
+    Qt comes with a number of plugins which are loaded at run-time when they are needed. These
+    can handle anything from connecting to SQL databases to loading specific image formats.
+    Detecting plugin dependencies is impossible as the plugins are loaded at run-time, but
+    androiddeployqt tries to guess such dependencies based on the Qt dependencies
+    of your application. If the plugin has any Qt dependencies which are not also dependencies of
+    your application, it will not be included by default. For instance, in order to ensure that
+    the SVG image format plugin is included, you will need to add \c{QT += svg} to your \c .pro file
+    so that the \l{Qt SVG} module becomes a dependency of your application.
+
+    If you are wondering why a particular plugin is not included automatically, you can run androiddeployqt
+    with the \c --verbose option to get the list of missing dependencies for each excluded plugin. You
+    can achieve the same in Qt Creator by ticking the \gui{Verbose output} check box in the
+    \gui{Deployment configurations}. This is located in the \gui{Run} tab of your \gui{Projects}
+    settings.
+
+    It's also possible to manually specify the dependencies of your application. See the documentation
+    for the \c{ANDROID_DEPLOYMENT_DEPENDENCIES} qmake variable below.
+
     \section1 qmake variables
 
     Unless the project has special requirements such as third party libraries, it should be