Can App Inventor have a button or control that rotates on screen?

A reader asked: Is there is a way to have a control, such as a button, rotate on the screen?

With a simple trick, the answer is Yes!

The trick is to use ImageSprites that are made to look like buttons. Then, instead of .Click event handler, as used on a Button, we use one of the “touch” events defined for the ImageSprite class. To rotate the sprite, change the sprite’s Heading property. Easy!

If you would like to learn more about ImageSprites, please read my online tutorial “Using ImageSprites for animated App Inventor Graphics”.

I’ve also written an inexpensive 227 page e-book all about graphics, animation and charts available from many online e-book outlets. You may find that text helpful to you as well.

Tutorial Video

The tutorial is shown here as a video – or page down for a written version of the tutorial.

User View

Watch this video to see what a rotating button looks like:

Designer View

Creating the user interface is the same as creating other App Inventor user interfaces – except we use a graphical drawing area called the Canvas and add an ImageSprite to the Canvas.

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Example of the new App Inventor “Responsive Design” Feature

MIT App Inventor introduced today their new “responsive design” features so that apps can work “better” on different sized screens. Using these new features, you can create a single app that should run on both a smart phone and a tablet, yet still display proportional user interface controls. Prior to this, your nicely designed smart phone app could end up having very small buttons or text boxes when run on a tablet; now, these components will resize as needed.

The name “responsive” comes from the ability of the app to “respond” to the size of the device and to change the size of controls so they maintain a similar size on each device. The terminology “responsive web design” also refers to web sites that are designed to work with different sized mobile device screens – here is a link to a great article about responsive web site design, passed to us by reader David – thanks!

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MIT begins testing “App Inventor Extension Components”

MIT has begun testing a new App Inventor feature that will enable developers to create their own “extension components”. Extension components are written in Java. Once created and tested, these new components may be shared with other App Inventor developers for use in programs.

What this means: if App Inventor lacks a feature or capability, then a Java developer familiar with App Inventor and its components software development kit will be able to add new features to App Inventor. Over time, the capabilities and power of App Inventor are likely to grow enormously – and rapidly. The ability to extend App Inventor’s features/components is an exciting and tremendously important development for the future of App Inventor!

For now, this feature is in “test mode”.

Source: App Inventor Extension Components available for testing | Explore MIT App Inventor