Automatically Returns to Other Page

[jed_818]

In my APK-installed app, whenever I log in and get redirected to another page, the page unexpectedly closes and returns to the login screen.

Since the app is connected to an Arduino via Bluetooth, it’s supposed to automatically establish the Bluetooth connection after logging in.

Can anyone help me figure out what’s going wrong?

[Taifun]

@jed_818

the page unexpectedly closes

Use logcat to find out what's going on

Capturing Device Logs using adb logcat

ADB is a command-line utility that that can be used to control your device over USB from a computer. It will allow you to install / uninstall and or view logs on your device. This could be very handy when there are issues with a specific app and you like to view the logs for information that may lead to identify the cause of error. In this post, we’ll discuss how to install and use ADB. Installation: ADB comes with Android SDK. However, you can download ONLY the ADB files from HERE . EDIT: …

Taifun

[ABG]

Switching screens breaks Bluetooth connections.

Use stacked vertical arrangements instead, only one visible at a time.

Also,

Be sure to use println() at the end of each message to send from the sending device, to signal end of message.

Only use print() in the middle of a message.

Be sure not to println() in the middle of a message, or you will break it into two short messages and mess up the item count after you split the message in AI2.

Do not rely on timing for this, which is unreliable.

In the AI2 Designer, set the Delimiter attribute of the BlueTooth Client component to 10 to recognize the End of Line character.

Also, return data is not immediately available after sending a request,
you have to start a Clock Timer repeating and watch for its arrival in the Clock Timer event. The repeat rate of the Clock Timer should be faster than the transmission rate in the sending device, to not flood the AI2 buffers.

In your Clock Timer, you should check

  Is the BlueTooth Client still Connected?
  Is Bytes Available > 0?
     IF Bytes Available > 0 THEN
       set message var  to BT.ReceiveText(-1) 

This takes advantage of a special case in the ReceiveText block:

ReceiveText(numberOfBytes)
Receive text from the connected Bluetooth device. If numberOfBytes is less than 0, read until a delimiter byte value is received.

If you are sending multiple data values per message separated by | or comma, have your message split into a local or global variable for inspection before trying to select list items from it. Test if (length of list(split list result) >= expected list length) before doing any select list item operations, to avoid taking a long walk on a short pier. This bulletproofing is necessary in case your sending device sneaks in some commentary messages with the data values.

Some people send temperature and humidity in separate messages with distinctive prefixes like "t:" (for temperature) and "h:" (for humidity).
(That's YAML format.)

The AI2 Charts component can recognize these and graph them. See Bluetooth Client Polling Rate - #12 by ABG

To receive YAML format messages, test if the incoming message contains ':' . If true, split it at ':' into a list variable, and find the prefix in item 1 and the value in item 2.

[jed_818]

I only need the bluetooth in 1 screen

this screen is used to wait for the value to be received, then open a new screen upon receiving

[ABG]

(Canned Reply: ABG- Export & Upload .aia)
Export your .aia file and upload it here.

[ABG]

Use stacked Vertical Arrangements instead of multiple Screens.

Only make one .Visible at a time.

This avoids a lot of grief with screen switching.