Building RingQt Applications for Mobile

In this chapter we will learn about Building RingQt Applications for Mobile.

Download Requirements

Check the next link : http://doc.qt.io/qt-5/androidgs.html

Download

• The Android SDK Tools

  https://developer.android.com/studio/index.html

• The Android NDK

  https://developer.android.com/ndk/index.html

• Apache Ant v1.8 or later

  http://ant.apache.org/bindownload.cgi

• Java SE Development Kit (JDK) v6 or later

  http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html

Update the Android SDK

Update the Android SDK to get the API and tools packages required for development

Install Qt for Android

• You can install Qt for Android from the next link

  https://download.qt.io/archive/qt/5.5/5.5.1/

• Run Qt Creator, Select Tools > Options > Android to add the

  Android NDK and SDK paths.

  http://doc.qt.io/qtcreator/creator-developing-android.html

• Using Qt Creator Open the project

  Folder : ring/android/ringqt/project

  Project file : project.pro

• You will find the code in resourcestest.ring

  You can modify the code then build and run for Desktop or Mobile.

Comments about developing for Android using RingQt

1. The main project file is main.cpp

   This file load Ring Compiler/Virtual Machine and RingQt

   Then copy files during the runtime from the resources to temp. folder

   Then run the test.ring

   Through main.cpp you can extract more files from the resources to temp. folder once you add them (create projects with many files).

2. The next functions are missing from this Ring edition

   • Database (ODBC, SQLite & MySQL)
   • Security and Internet functions (LibCurl & OpenSSL)
   • RingAllegro (Allegro Library)
   • RingLibSDL (LibSDL Library)

   Just use Qt Classes through RingQt.

   For database access use the QSqlDatabase Class

Note

All of the missing libraries ((LibCurl, OpenSSL & Allegro) can be compiled for Android, but they are not included in this Qt project.

3. use if isandroid() when you want to modify the code just for android

Example:

if isandroid()
        // Android code
else
        // other platforms
ok

(4) Sometimes you will find that the button text/image is repeated in drawing ! it’s Qt problem that you can avoid using the next code.

if isandroid()
        setStyleSheet("
                border-style: outset;
                border-width: 2px;
                border-radius: 4px;
                border-color: black;
                padding: 6px;")
 ok

5. Always use Layouts instead of manual setting of controls position and size.

This is the best way to get the expected user interface to avoid problems like (controls with small/extra size)

6. When you deal with Qt Classes you can determine the images from resources (you don’t need to copy them using main.cpp)

Example:

if isandroid()
    mypic = new QPixmap(":/resources/cardsimage")
else
    mypic = new QPixmap("cards.jpg")
ok

In the previous example, cards.jpg is added to the resources then we write the “cardsimage” as alias for “cards.jpg”