December 15th 2014, QtTorch App

Decemver 14th 2014 SQLite Efficient searching | | December 27th 2014 APK Size Reduction

Today we are going to publish a first app to the Google Play Store. It will be nothing special, just a simple app that enables the torch light of an Android phone

With this simple app we are going to excercise the steps necessary for publishing an Android app:

Step 1) Prepare an APK

We are simply going to reuse libpong’s functionality to switch a led flash light on or off via JNI as described here. Then we create a Qt program which adds a single QPushButton to a QVBoxLayout inside of a QWidget, add some fancy stuff like a custom qss style sheet and that’s our torch app. We call it “QtTorch”:

Step 2) Create a nice icon


The above icon was created with Inkscape and exported to a 512×512 PNG image /w alpha.

In QtCreator open the Android manifest and select the above image for the app icon.

Step 3) Sign the APK

In QtCreator select Projects > Run > Package configurations and unfold the “Deploy Configurations” section:

  • “Create” a new “Keystore” file (*.keystore) in a safe place (meaning that it gets a backup ;-)
  • Make sure that “Sign Package” is checked and that the correct certificate alias selected.
  • Remember the password of the keystore.

Note: Do not use Qt 5.3.1 as signing the apk will not work (QTBUG-41021). Using Qt 5.4.0 is also not recommended at the time of this writing. It works with the latest Qt 5.3.2:

Step 4) Register with the Android Developer site:

  • Sign in with your gmail account.
  • Pay 25 bucks with a credit card.
  • Register your developer profile.

Step 5) Upload the App

On the Android Developer Console supply:

  • Signed APK
  • Both a short and a detailed description
  • A screen shot (press and hold power and level— on your phone to make a screen shot)
  • Hi-res symbol
  • Image describing the function of the app
    • 1024×500 PNG /wo alpha
  • Various app-specific options and play store settings

Step 6) Publish the App

After publishing the app, it will take several hours until it shows up in the Google Play Store:

Decemver 14th 2014 SQLite Efficient searching | | December 27th 2014 APK Size Reduction