ICS webinar given by Justin Noel, Feb. 23, 2017

1. © Integrated Computer Solutions, Inc. All Rights Reserved
10 Keys to Ensuring Success
for Your Next Qt Project
Justin Noel
Senior Consulting Engineer, ICS, Inc.
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2. © Integrated Computer Solutions, Inc. All Rights Reserved
The Right Tools
• Qt is huge!
• Study the API and docs for hidden treasure:
• QML Styling: QQmlFileSelector
• Web Services: QNetworkAccessManager
• There are other toolkits to help
• Boost, Vtk, FFMpeg, libusb
• Don’t be afraid to look around for solutions
• Complex video rendering?
• Maybe QtMultimedia fits. Maybe not.
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The Right People
• Staff the project up early.
• Don’t hold your “big push” for the end
• Consult with experts (internally or externally)
• For each of your “hard parts”
• Also for each toolkit
• Get training!
• Avoid re-inventing the wheel!
• Get advice early!
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User Experience (UX)
• User Experience is vital to a project’s success
• Start early with a Human Centered Design
• Good UX should optimize and simplify the user’s workflow
• Especially true for embedded devices and mobile
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Iterative UX
• Engineering must be a stake holder in all UX activity
• Make sure UX maps to realities of HW and SW stack
• Rework UX? Or does the stack need changing?
• User Experience process needs to be iterative just like the software process
• UX needs to start the project a month ahead of engineering
• You will catch them. Also you will need UX support.
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Be Agile
• Agile is more than just daily standups and design on demand
• Although both of these help quite a bit
• The next 5 points are all agile related
• Keep standup very short. Three questions:
• What did I do yesterday?
• What will I do today?
• Does anything prevent work from continuing?
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Test Early
• Earlier you can test code the more traceable it is.
• What went wrong? Why?
• Can we stop it from happening again?
• Is our pattern wrong?
• QTest is good unit testing framework
• Has Qt specific things: Test events and signals
• GTest and GMock are much more powerful
• Qt compatible. Can use features of QTest
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Be Testable
• Structure code and design
to be testable
• Build as libraries, DI,
Signals/Slot Interfaces
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Backend.dll
App.exe
(only main.cpp)
Ui.dll
BackendTests.exe UiTests.exe
C++ Test Fixtures QML Test Fixtures

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Layered Design
Qt and a Layered Design can help Testability and Demo-ability
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Signals
Up
Visualization Layer (QML)
Presentation Layer (QObjects)
Data Layer (Local Data Storage)
Communications Layer (TCP)
Calls
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QML as Visualization Only
• The best QML advice is Keep It Simple!
• QML is the best UI visualization toolkit
• Let it do what it does best: Draw and Animate.
• Let C++ classes take care of the rest
• Business logic, Storage, etc
• Even UI flow in some cases
• See the Qt State Machine talks!
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Always Be Delivering
• Deliver from Day 1
• Spend Day 0 setting up a Continuous Integration Server
• Create installer scripts for what little code you have
• Always be ready to distribute or demo the code.
• Being able to run “off device” is quite helpful for getting stake holder feedback.
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Always Be Reviewing
• Code review is essential
• Is the code correct?
• Does it follow project patterns and style?
• Cross-pollination of developer knowledge
• Code review servers are best
• ICS suggests Gerrit
• Pre-commit checks / review
• Same system that the Qt Project uses
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Don’t Be Too Agile
• Know your schedule.
• It’s easy to put off creating stories until immediately before the sprint starts.
• Create rough estimates for large tasks as soon as they are known
• Don’t need to be super accurate. Iterate over time.
• Points or time
• Having these will provide a rough estimate for completion
• Also as new requirements arise you can predict schedule impact
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Checklist Big Items
• You should know what to expect for “the hard parts”
• External Interfaces
• Fancy Renderings
• Performance Requirements
• Create a checklist and assign research tasks
• Find “Unknown Unknowns”
• These can kill your schedule if they arise late
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Internationalize Early
• Internationalize from Day 1
• Wrap user visible string in tr / translate
• Use QLocale for all numbers and dates
• Create a dummy translation file for testing
• A script can update a .ts with fake translations
• Be sure to use some non-latin1 characters
• Verify all the strings / dates / numbers change
• As you deliver each screen!
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Thank You!
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Justin Noel
Senior Consulting Engineer, ICS, Inc.