Mobile Device Features 1: Difference between revisions

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[[File:Cameraimage.jpg]]
[[File:Cameraimage.jpg]]
* May not be supported on older devices
* May not be supported on older devices
* Done using a [[TextBox]], with inputType set to 'file'.
* Once the user has taken or selected a picture, a PictureBox on the form is updated.
* Once the user has taken or selected a picture, TxtBox_onchange is executed:
<pre>
reader = new FileReader()
 
Function txtPhoto_onchange()
  reader.readAsDataURL(txtPhoto.files[0])
End Function
</pre>
* Reading the picture in is asynchronous: pictures can be large and take time to load.
* Reading the picture in is asynchronous: pictures can be large and take time to load.
* Once the read is complete, reader_onload is called.
* Pictures can then be emailed or manipulated.
To display the picture, we need to put it into a PictureBox object.
Function reader_onload(e)
  'Now, let's put it in our PictureBox
  pb = pbPhoto.getContext("2d")
  pb.addImage(e.target.result,0,0,0,0,0,0,pbPhoto.width,pbPhoto.height)
End Function
</pre>


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Latest revision as of 16:57, 22 April 2014

In the next two segments, we will talk about some features that are unique to mobile devices and how to use them.


Camera

  • May not be supported on older devices
  • Once the user has taken or selected a picture, a PictureBox on the form is updated.
  • Reading the picture in is asynchronous: pictures can be large and take time to load.
  • Pictures can then be emailed or manipulated.

Emoji

  • Emoji are extended characters that are built into mobile devices.
  • There are hundreds of them: arrows, letters, roman numerals, pictures of food, building, transportation, flags, animals. And of course, happy faces, sad faces, crying faces.
  • They are saved as standard characters: each has its own character code number.
  • There is a complete list here: http://en.wikipedia.org/wiki/Emoji
  • Support varies by browser
  • Most mobile devices are OK
  • Desktop Safari works
  • Desktop Chrome needs an (but an extension to see these)
  • The characters are in the format &#xxxxxx; where xxxxxx is the decimal value
  • Cheeseburger is &#127828; (or &#x1F354 in hex)

Orientation

Mobile devices can be rotated. It's up to you to decide how you want your app to handle this.

  • The two orientations are referred to as Portrait and Landscape.
  • The layout of your form will be completely different between the two.
  • If you don't want to support rotation, add the Orientation control to your app. Set its screenOrientation property to portrait or landscape. When the screen is rotated, this message will appear:

  • If you do want to support orientation, you will want to take action when the screen is rotated
Function window_onorientationchange()
  'This function is called if the orientation of the device is changed.
  MsgBox "orientation changed to " & window.orientation
End Function
  • You can now resize and reposition your controls, using code like this:
Function window_onorientationchange()
  If Abs(window.orientation)=90 Then 'Landscape
    btnSubmit.Left="100px"
    btnSubmit.Top="100px"
  Else                               'Portrait 
    btnSubmit.Left="20px"
    btnSubmit.Top="120px"
  End If
End Function
  • You will have to do this to all controls which are affected.
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