Touchposé

Touchposé is a set of classes for iOS that renders screen touches when a device is connected to a mirrored display. Touchposé adds a transparent overlay to your app’s UI; all touch events cause semi-transparent circles to be rendered on the overlay--an essential tool when demoing an app with a projector (with an iPad 2 or iPhone 4S).

To use Touchposé in your own app, copy the QTouchposeApplication and QTouchposeWindow classes to your project.

Touchposé should work for most apps. It’s implemented by two classes: QTouchposeApplication, a UIApplication subclass; and QTouchposeWindow, a UIWindow subclass. QTouchApplication overrides ‑sendEvent: and is responsible for rendering touches on the overlay view. QTouchposeWindow should be used as the app’s main window; it overrides ‑didAddSubview: and ensures that the overlay view remains the top-most view.

To use Touchposé with an app:

• Use QTouchposeApplication instead of UIApplication. This is done by specifying the application class in UIApplicationMain:

    int main(int argc, char *argv[])
    {
        @autoreleasepool
        {
            return UIApplicationMain(argc, argv,
                                     NSStringFromClass([QTouchposeApplication class]),
                                     NSStringFromClass([QAppDelegate class]));
        }
    }
  

• Use QTouchposeWindow instead of UIWindow when creating your main window. This might be done in code (typcially ‑application:didFinishLaunchingWithOptions:), or in a nib file.

No other steps are needed. By default, touch events are only displayed when actually connected to an external device. If you want to always show touch events, set the alwaysShowTouches property of QTouchposeApplication to YES.

Known Issues

• Touchposé doesn’t work correctly with action sheets, alerts, or the keyboard. The issue is that these views are not added to the main window and end up on top of Touchposé’s overlay view thus obscuring the rendering of the touch events. For the keyboard, this isn’t too significant, because the keyboard already has a visual effect indicating where touches occur. I’d love to hear if there’s a way to get this working with alerts and action sheets.

• When Touchposé is enabled and the keyboard is displayed, the keyboard performance is severely impacted. Because of this, Touchposé is automatically disabled when the keyboard is shown and renabled when the keyboard is hidden.

• The finger touch views are not always removed when a touch ends. This appears to be caused by a bug in iOS: we don't get notified of all UITouch instances ending. See here for a discussion of this issue. I haven't investigated this issue extensively—it may only occur on versions of iOS prior to 5.

License

Touchposé is licensed under the Apache License, Version 2.0.