Detecting What is Supported

by kirupa   | filed under Flash and ActionScript

The Flash Player does a good job of allowing you to focus on creating cool content that works on a wide range of devices. Despite that, there are a handful of Flash features that not all devices support. An example of this is using the webcam on a device that doesn't actually have a webcam.

To help you gracefully handle situations where what you expect and what the device your content will be viewed on supports are not the same, you have the flash.system.Capabilities API.

The original example used a Flash movie to show what Flash features your system supports. Since modern browsers no longer run Flash content directly, the source code and the relevant ActionScript are included below instead.

The example uses almost all of the functions found in the Capabilities API to return whether a feature is supported or provide information on system settings such as the CPU, OS, Flash Player version, etc.

You can download the source code (Flash CS5.5 and CS4) for the above project or just glance at the various functions starting with Capabilities I used below:

Download the source code (Flash CS5.5 and CS4)

public function WhatToSupport() {
  // constructor code
  this.addEventListener(Event.ADDED_TO_STAGE, DetermineCapabilities);
}

private function DetermineCapabilities(e:Event) {
  SetEnabledOrDisabled(Capabilities.avHardwareDisable, cameraMicrophone);
  SetEnabledOrDisabled(Capabilities.hasAccessibility, accessibility);
  SetEnabledOrDisabled(Capabilities.hasAudio, audioPlayback);
  SetEnabledOrDisabled(Capabilities.hasAudioEncoder, encodingAudio);
  SetEnabledOrDisabled(Capabilities.hasEmbeddedVideo, embeddedVideo);
  SetEnabledOrDisabled(Capabilities.hasIME, imeInstalled);
  SetEnabledOrDisabled(Capabilities.hasMP3, mp3decoder);
  SetEnabledOrDisabled(Capabilities.hasPrinting, printing);
  SetEnabledOrDisabled(Capabilities.hasScreenBroadcast, screenbroadcast);
  SetEnabledOrDisabled(Capabilities.hasScreenPlayback, screenplayback);
  SetEnabledOrDisabled(Capabilities.hasStreamingAudio, streamingAudio);
  SetEnabledOrDisabled(Capabilities.hasStreamingVideo, streamingVideo);
  SetEnabledOrDisabled(Capabilities.hasTLS, sslSockets);
  SetEnabledOrDisabled(Capabilities.hasVideoEncoder, encodingVideo);
  SetEnabledOrDisabled(Capabilities.isDebugger, debugVersion);
  SetEnabledOrDisabled(Capabilities.isEmbeddedInAcrobat, embeddedPDF);
  SetEnabledOrDisabled(Capabilities.localFileReadDisable, hardDrive);
  SetEnabledOrDisabled(Capabilities.supports32BitProcesses, thirtyTwoBit);
  SetEnabledOrDisabled(Capabilities.supports64BitProcesses, sixtyFourBit);

  touchScreen.text = Capabilities.touchscreenType;
  flashVersion.text = Capabilities.version;
  cpu.text = Capabilities.cpuArchitecture;
  language.text = Capabilities.language;
  manufacturer.text = Capabilities.manufacturer;
  h264idc.text = Capabilities.maxLevelIDC;
  osValue.text = Capabilities.os;
  pixelaspectratio.text = Capabilities.pixelAspectRatio.toString();
  runtimeEnvironment.text = Capabilities.playerType;
  screenColor.text = Capabilities.screenColor;
  screenDPI.text = Capabilities.screenDPI.toString();
  horizontalResolution.text = Capabilities.screenResolutionX.toString();
  verticalResolution.text = Capabilities.screenResolutionY.toString();
}

private function SetEnabledOrDisabled(supported:Boolean,
                                      yesOrNoInstance:MovieClip) {
  if (supported) {
    yesOrNoInstance.gotoAndStop(1);
  } else {
    yesOrNoInstance.gotoAndStop(2);
  }
}

I am not going to describe the various functions in this article, for Adobe's documentation on this is fantastic. Just read the documentation and refer to the source code and example you see in this page for some guidance to see how it is used.

Conclusion

There you have it: an introduction to the easy-to-use Capabilities API via a sample project and Adobe's documentation. If you are ever using a feature whose existence is dependent on the device your content will be viewed on, strongly consider checking to see if the feature exists and giving users some notice about why your content won't work as expected for them!

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