Share My Creation GPS Example

dlfallen · Dec 21, 2011

On the tablet zoom issue - In my GPSlog program I am able to zoom by using the usual 2-finger pinch method. This does not work in Klaus' GPS example because touching the screen causes a vertical and horizontal line to be drawn, along with the GPS coordinates of the point being touched. I like that feature a lot, but zooming is more important to me.

Would it be possible to add a button to toggle between your default coordinate mode and the zoom mode? Then you could have the best of both worlds.

I experimented with a custom zoom control in my program which worked well in map mode, but not in satellite mode. The problem is that the button resent the google maps request (at the new zoom level) and that request always defaults to the map view. Is there any way to change that default?

By the way Klaus, I agree whole heartedly with all of the folks giving you praise for your GPS example. I too think it is wonderful.

klaus · Dec 21, 2011

Thank you for the compliment.

Would it be possible to add a button to toggle between your default coordinate mode and the zoom mode?

It's already in there

.
Just touch the MAP button, move up to change to the draggable mode and release it, this works vice and versa. Can also be set in the setup 'Map draggable'. Explained in the short help file. The last setup is saved when you quit the program.

I will look at the map / satellit mode. When the map is redrawn by the program it is always in map mode.

I like your inputs, thank's for testing. That's the best and only way to improve programs.

Best regards.

Tom Christman · Dec 21, 2011

Klaus, your contributions are greatly appreciated. It is truly a treat to view your code......concise and elegant. Thank You for this!
Tom

klaus · Dec 21, 2011

Version 1.2 updated in the first post.
Added the 'maptypeid_changed' event to memorize the selected map type reported by dlfallen in post #21.

@dlfallen
I set the ZoomControl type to LARGE.
Could you please test the new version to see if this solves the zoom control problem on the tablet.

@ Tom Christman, thank's

.

Best regards.

dlfallen · Dec 21, 2011

Yes! The zoom control is now visible on my 10 in. tablet. I will have to try to get this to work in my program as well.

BTW, your map still exhibits this curious behavior (previously reported): When viewing the map, if you click on the Setup icon and then the Back button, the map displays at the fully zoomed in level rather than the level it was at before. Curious.

God Jul!

klaus · Dec 22, 2011

Version 1.3 in the first post.

@dlfallen,
Could you please test it once more with the zoom problem.
If you still get the problem could you look what happens in the CalcMapZoom routine in the Main module. I suspect that the problem was (is) there. I had never seen it.
Do you use it in landscape mode ? Normaly it shouldn't.

Best regards.

dlfallen · Dec 22, 2011

V 1.3 does seem to solve the zoom problem, but two new problems appear:

(1) I keep getting the error message:

An error has occurred in sub.main_gps_locationchanged (java line: 1436)
Java.lang.RuntimeException: Object should first be initialized (Location).

(2) When viewing a map, if I click on the GPS icon I get the view showing latitude, latitude, and altitude but it quickly shifts back to the map view.

I am using the program in portrait mode only.

klaus · Dec 23, 2011

Once more thank's for testing. Version 1.4 in the first post

1) OK
2) It's a 'normal' behaviour. When you have a map displayed and you click on the GPS button, the program shows the map centered to the default center coordinates and the default zoon level. Then after getting the first fix, the map is centered to this fix and the fix is dispayed on the map (if 'Show GPS on map' is checked in the setup). The next fixes are shown on the map, when the fix gets near an edge of the screen the map is centered to the last fix. You can use the map controls in this mode, like the zoom.

Best regards.

latcc · Dec 25, 2011

What an excellent and first class App, Klaus! I am amazed.

I have a question. You use waypoints on a google earth map. Do you create these as GE points of interest files? I am trying to find code that creates a point of interest in google earth POI 'kml' format.

klaus · Dec 25, 2011

No the points are saved in an internal format.

It shouldn't be that complicated to write POIs in kml format.

Best regards.

Smee · Dec 26, 2011

Klaus,

I too would like to add my thanks and praise. This really is an excellent well written program.

Congratulations and thank you very much for sharing. I am sure i will learn plenty from your code

Joe

timo · Dec 26, 2011

Very well done, bravo Klaus.
Just one thing I noticed on distributing GPS apps: not all users are 'Androidians' and they may be in difficulties with this Intent:
'StartActivity(GPS1.LocationSettingsIntent)'; they often close the setting page by the 'home' button instead of the 'back' one. This make them be unable to propely reopen the app: if the app is still resident, they are forced to come back to the GPS setting page and remain confused. That's why I usually only show a msgbox pleasing them to set GPS 'on' and then to reopen the app. (I close with activity.finish after the msgbox).
This naturally depends on your consumer's target age.

AlpVir · Dec 27, 2011

The project is very interesting and offers interesting insights to each of us to improve your code.
However, it has, like all the examples I have so far been able to find a serious mistake in the calculation because of the height (as I understand it) does not take into account the geoid.
Basically I live to 545 m above sea level. My system hardware/software "external antenna --> Motorola Defy ---> TwoNav" correctly indicates 550 m or so.
Also use that, the internal antenna result (almost perfect) does not change.
The app. GPSExample indicates 595 m, very very different.
The difference (about 50 m) corresponds precisely to the result of the calculation done with the software "ClenGui.exe" (NIMA WGS 84 Calculator) or that derived from the computer on-line
http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm96/intpt.html

It might be useful "EGM96Geoid.c" (easily available online) that should correct this error, but is written in C.
It is worth rewriting it in B4a or are there better solutions?
Or take a solemn corner?

latcc · Dec 27, 2011

timo said:
Very well done, bravo Klaus.
Just one thing I noticed on distributing GPS apps: not all users are 'Androidians' and they may be in difficulties with this Intent:
'StartActivity(GPS1.LocationSettingsIntent)'; they often close the setting page by the 'home' button instead of the 'back' one. This make them be unable to propely reopen the app: if the app is still resident, they are forced to come back to the GPS setting page and remain confused. That's why I usually only show a msgbox pleasing them to set GPS 'on' and then to reopen the app. (I close with activity.finish after the msgbox).
This naturally depends on your consumer's target age.

If some users press HOME when they should be pressing BACK they deserve to remain confused.

Do you really believe it is necessary to cater for those who misuse their device in this way, Timo? If you add messages when a user mis-uses the buttons how are they ever going to learn to do things correctly?

timo · Dec 27, 2011

I know my chicken; I code for golfers

klaus · Dec 27, 2011

@latcc,
You find an update of the program in the first post with saving of a GPS path in Google Earth KML format.

@AlpVir,
I had noticed that too, but haven't taken the time yet to look at it.
In the Basic4PPC GPS Driver library there is a SeeLevelAltitude property that gives the correct altitude. Unfortunately it seems that Android GPSs' don't have it (a bit disapointing).

@timo,
Depends on the 'consumers', some seem to be more open to adapt than others

.

Best gerards.

timo · Dec 27, 2011

Klaus, this code let GPS1 be stopped if you push, by chance, on the left button (menu) because of this select case statement.
In this case i think it is better let the GPS1.Stop be managed by the Activity_pause or manage that pressure in the statement too.
What do you think about?
Ciao.

B4X:

Sub Activity_KeyPress (KeyCode As Int) As Boolean 
   Dim Answ As Int
   Dim txt As String
   
   Activity.Title = ProgName & " : " & ProgVersion

   Select KeyCode
   Case KeyCodes.KEYCODE_BACK
      txt = "Do you really want to quit the program"
      Answ = Msgbox2(txt, "A T T E N T I O N", "Yes", "", "No", Null)
      If Answ = DialogResponse.NEGATIVE Then
         Return True
      End If
   End Select
   GPS1.Stop
   SaveSetup
   Return False   
End Sub

klaus · Dec 28, 2011

Hi timo,
Thank you for pointing this out.
I modified the code like this:

B4X:

Sub Activity_KeyPress (KeyCode As Int) As Boolean 
    Dim Answ As Int
    Dim txt As String
    
    Activity.Title = ProgName & " : " & ProgVersion

    Select KeyCode
    Case KeyCodes.KEYCODE_BACK
        txt = "Do you really want to quit the program"
        Answ = Msgbox2(txt, "A T T E N T I O N", "Yes", "", "No", Null)
        If Answ = DialogResponse.NEGATIVE Then
            Return True
        Else
            GPS1.Stop
            SaveSetup
            Return False    
        End If
    End Select
End Sub

Best regards.

legion48 · Dec 28, 2011

Klaus, I can't get the example to run. I get this message:

Compiling code. Error
Error parsing program.
Error description: Unknown type: webviewextras
Are you missing a library reference?
Occurred on line: 138
Dim MapViewerExtra As WebViewExtras

The libraries that are referenced are:

Core
Dialogues
GPS
JSInterface
Phone
RandonAccessFile

Am I missing a reference?

warwound · Dec 28, 2011

Hi legion48

You need WebViewExtras and NOT JSInterface.

Martin.

Share My Creation GPS Example

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