Google App Inventor

[ardhuru]

Wondering if anyone has any experience with the Google App Inventor?

I'd like to build a very simple app that displays a numeric keypad, and then simply outputs it to the phone's bluetooth.

Apparently from what I read, the App Inventor is a very simple package to develop Android apps, without having to go the Eclipse way. Also pretty much designed for the hobbyist, as it has canned commands to control Lego Mindstorms, letting you use all sensors on the Android in your project.

Would love to share information if anyone's been at it.

Regards,

Anand Dhuru

[mackrackit]

The App Inventor is/was "OK", but the future of it is questionable. Google is shutting it down. MIT is going to do something with it though. The way it is with Google everything is online, that may or may not be a good thing. It also seemed to be a bit limited in what you could do, IMHO. Kind of like using a "site builder" for a web site.

Have you seen B4A?
http://www.basic4ppc.com/index.html
I am really liking it. One of the nice features is the ability to debug on a device over your lan.

If you do decide to go with B4A use coupon code "bovvkr" to get %50 off the enterprise edition.

[ardhuru]

Thanks for the information, Dave.

The main thing that atrracted me to App Inventor was the ease with which one can use modules like BT, light sensor, accelerometer and so on, especially BT. How easy is it to use bluetooth with B4A? Have you used it?

At the price though, after the discount, it does look too tempting to pass.

BTW, as of September XX, I believe App Inventor is now hosted on the MIT server, and fully usable, so the accessibility should not be a problem, at least in the near future.

If you have used B4A, I would love to know your specific usage(s), as also about the learning curve, before I take the plunge.

Regards,

Anand

[mackrackit]

I have not used BT yet. Used the GPS, compass/accelerometer, write/read to storage... Currently I am working on a database app for an archaeologist that will record position and user entered attributes, with the ability to sync the data once the device is back into cell/wifi range. The learning curve for me was less than App Inventor. I never really made anything useful with App Inventor... But that is me.

Here is the code for a test app when I started playing with the GPS and the other orientation things.
The apk is attached if you want to see what it does.

'Activity module
Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Dim GPS1 As GPS
    Dim Orientation As PhoneOrientation
    'Compass Stuff
    Dim Angle As Float                
    Dim Timer1 As Timer
End Sub


Sub Globals
    'These global variables will be redeclared each time the activity is created.
    'These variables can only be accessed from this module.
    Dim Button1 As Button
    Dim Button2 As Button
    Dim Button3 As Button
    Dim Button4 As Button
    Dim ScrollView1 As ScrollView
    Dim lblAcu As Label
    Dim lblAlt As Label
    Dim lblLat As Label
    Dim lblLon As Label
    Dim lblSatellites As Label
    Dim lblSpeed As Label
    Dim pnlTest As Panel
    Dim Alt    As    Double
    Dim Rate As Double
    Dim Acu As Double
    Dim Latx As Double
    Dim Lonx As Double
    Dim now As Long
    Dim lblBear As Label
    Dim lblCompass As Label
    'Compass Stuff
    Dim csvCompass, csvNeedle As Canvas
    Dim bmpCompass, bmpNeedle As Bitmap
    Dim imvCompass, imvNeedle As ImageView
    Dim RectCompass, SRectNeedle, DRectNeedle As Rect
    
    
End Sub


Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("Main")
    ScrollView1.Panel.LoadLayout("scrollviewlayout")
    ScrollView1.Panel.Height = pnlTest.Height
    EditMode
    If FirstTime Then
        GPS1.Initialize("GPS")
    End If
    If File.ExternalWritable = True Then 
        Msgbox("Can write to SD storage card!", "") 
        Return 
    End If
    WriteTextWriter
End Sub


Sub Activity_Resume
    If GPS1.GPSEnabled = False Then
        ToastMessageShow("Please enable the GPS device.", True)
        StartActivity(GPS1.LocationSettingsIntent) 'Will open the relevant settings screen.
    Else
        GPS1.Start(0, 0) 'Listen to GPS with no filters.
    End If
    Orientation.StartListening("Orientation")
End Sub


Sub Activity_Pause (UserClosed As Boolean)
    GPS1.Stop
    Orientation.StopListening
End Sub
Sub GPS_LocationChanged (Location1 As Location)
    lblLat.Text = "Lat = " & Location1.ConvertToMinutes(Location1.Latitude)
    lblLon.Text = "Lon = " & Location1.ConvertToMinutes(Location1.Longitude)
    Latx = Location1.Latitude
    Lonx = Location1.Longitude
    ' 1 meter per second = 2.23693629 miles per hour
    Rate = Round2(Location1.Speed * 2.23693629,3)
    lblSpeed.Text = "Speed (MPH)= " & Rate
    ' 1 meter = 3.2808399 feet
    Alt = Round2(Location1.Altitude * 3.2808399,3)
    lblAlt.Text = "Altitude (Feet)= " & Alt
    Acu = Round2(Location1.Accuracy * 3.2808399,3)
    lblAcu.Text = "Accuracy (Feet)= " & Acu
    lblBear.Text = "GPS Bearing = " & Location1.Bearing
End Sub


Sub GPS_UserEnabled (Enabled As Boolean)
    ToastMessageShow("GPS device enabled = " & Enabled, True)
End Sub


Sub GPS_GpsStatus (Satellites As List)
    lblSatellites.Text = "Satellites:" & CRLF & _
    "#  SNR Used  Azi  Elev" & CRLF
    For i = 0 To Satellites.Size - 1
        Dim Satellite As GPSSatellite
        Satellite = Satellites.Get(i)
        lblSatellites.Text = lblSatellites.Text & CRLF & Satellite.Prn & _
            "  " & Satellite.Snr & "  " & Satellite.UsedInFix & "  " & Satellite.Azimuth _ 
            & "  " & Satellite.Elevation
    Next
End Sub
Sub Button1_Click
      WriteTextWriter
      Msgbox("The date is: " & DateTime.Date(now) & CRLF & _
    "The time is: " & DateTime.Time(now), "") 
End Sub
Sub Button2_Click
    ReadStringExample
End Sub


Sub ReadStringExample 
    Msgbox(File.ReadString(File.DirRootExternal, "MAC_GPS.txt"), "") 
End Sub 
Sub WriteTextWriter() 
    
    now = DateTime.Now
    Dim TextWriter1 As TextWriter 
    TextWriter1.Initialize(File.OpenOutput(File.DirRootExternal,"MAC_GPS.txt", True)) 
  '  For i = 1 To 10 
  '      TextWriter1.WriteLine("Line" & i) 
  '  Next 
      TextWriter1.WriteLine("Date = " & DateTime.Date(now))
    TextWriter1.WriteLine("Time = " & DateTime.Time(now))
    TextWriter1.WriteLine("Lat = " & Latx)
    TextWriter1.WriteLine("Lon = " & Lonx)
    TextWriter1.WriteLine("Alt = " & Alt)
    TextWriter1.WriteLine(" ")
    TextWriter1.Close 
End Sub 
Sub Orientation_OrientationChanged (Azimuth As Float, Pitch As Float, Roll As Float)
    lblCompass.Text = "Compass = " & Azimuth
    Angle = Azimuth
    Timer1_Tick
End Sub
Sub Timer1_Tick
    csvNeedle.DrawRectRotated(DRectNeedle,Colors.Transparent,True,1,0)
    csvNeedle.DrawBitmapRotated(bmpNeedle,SRectNeedle,DRectNeedle,0)
    csvCompass.DrawBitmapRotated(bmpCompass,RectCompass,RectCompass,-Angle)
    imvCompass.Invalidate2(RectCompass)
End Sub
Sub EditMode()
    'Compass Stuff
    Dim x, y As Float


    bmpCompass.Initialize(File.DirAssets,"compass.png")
    bmpNeedle.Initialize(File.DirAssets,"needle.png")
    
    imvCompass.Initialize("")
    imvCompass.Bitmap = bmpCompass
    imvNeedle.Initialize("")
    imvNeedle.Color=Colors.Transparent
    
    x = 30 ' (100%x - bmpCompass.Width)/2
    y = 410 '(100%y - bmpCompass.Height) / 2
    ScrollView1.Panel.AddView(imvCompass, x, y, bmpCompass.Width, bmpCompass.Height)
    ScrollView1.Panel.AddView(imvNeedle, x, y, bmpCompass.Width, bmpCompass.Height)
    csvCompass.Initialize(imvCompass)
    RectCompass.Initialize(0, 0, bmpCompass.Width, bmpCompass.Height)


    csvNeedle.Initialize(imvNeedle)
    x = (bmpCompass.Width - bmpNeedle.Width)/2
    y = (bmpCompass.Height - bmpNeedle.Height)/2
    SRectNeedle.Initialize(0, 0, bmpNeedle.Width, bmpNeedle.Height)
    DRectNeedle.Initialize(x, y, x + bmpNeedle.Width, y + bmpNeedle.Height)
    
    Timer1.Initialize("Timer1",200)
    Timer1_Tick
    
End Sub

[dhouston]

Anand,

I've been too busy with 15 different PCB prototypes to spend much time with B4A so I can't add to what Dave has said but everyone I know who has it has been impressed. There's a user forum that should give you a good idea of how it is used and how well it is supported. Anybody familiar with any dialect of procedural Basic (and especially VB) should find it easy to learn.

[ardhuru]

Dave (macrackit), thanks for the code; a working piece of code should be an excellent starting point while learning.

Dave (Houston), I remember you had referred to B4A in an earlier thread as well, and had meant to try it out back then, but somehow got relegated to the background. I see from the forums and the projects sub-section that people have done some pretty fancy things with B4A. What I need seems pretty trivial in comparison, so I'm pretty sure its doable.

I'll report back with the progress as I go.

Thanks, guys.

Anand