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Tech Note 8: Extended button support in Kinoma Play for Windows Mobile

• Initial Version: May 29, 2009

Summary

Kinoma Play implements support for several buttons that are not commonly supported on Windows Mobile devices. The information in the tech note is intended for device manufacturers and hackers who want to add support for additional buttons to Kinoma Play.

Media and Browser buttons

• VK_MEDIA_PLAY_PAUSE — Play/pause the now playing item
• VK_MEDIA_PREV_TRACK — Go to the previous item in the current play list
• VK_MEDIA_NEXT_TRACK — Go to the next item in the current play list
• VK_MEDIA_STOP — Stop the now playing item. Sending VK_MEDIA_PLAY_PAUSE resumes playback.

These buttons have the same function as the corresponding buttons on a Bluetooth headphone remote control. In addition, one browser button is supported:

• VK_BROWSER_HOME — From any screen other than the home screen within Kinoma Play, jumps to the Kinoma Play home screen. When pressed on the Kinoma Play home screen, the Kinoma Play window is hidden revealing the application behind it (like the OK button).

The following code shows how to send one of the buttons:

HWND hwnd = FindWindow( NULL, "Kinoma Play");
if (hwnd) {
	PostMessage(hwnd, WM_KEYDOWN, VK_MEDIA_PLAY_PAUSE, 1 << 24);
	PostMessage(hwnd, WM_KEYUP, VK_MEDIA_PLAY_PAUSE, 1 << 24);
}

As shown in this preceding sample code, Kinoma recommends sending both the key down and key up events, and searching for the window by name, not by class name.

OK button

On some Pocket PC edition phones, the OK button can be intercepted by applications. Unfortunately, the key code varies depending on the device. Kinoma Play contains a registry entry which can be used to configure the OK button behavior.

The registry key is HKEY_LOCAL_MACHINE > Software > Kinoma > Player 5. The value is vk_ok, which has a type of DWORD. If the value is non-zero, then Kinoma Play treats WM_KEYDOWN and WM_KEYUP events with this key code with the behavior documented above for VM_BROWSER_HOME. If you know key code for the OK button on your phone, put it into vk_ok. Changes to vk_ok are only checked at start-up, so you will need to restart Kinoma Play for any changes to take effect.

On the Palm Treo Pro, Kinoma Play automatically maps the OK button to VK_BROWSER_HOME. To disable this behavior, set vk_ok to 0. When vk_ok is 0, OK button processing in Kinoma Play is disabled.