Develop Reference

Qt BLE For Android: Characteristic update does not trigger characteristicChanged signal

Here is the thing a device that we have transmits regular updates of a custom characteristic of a custom service. The service and characteristic in this device is defined via a XML file. This, of course, is referring to the Bluetooth BLE protocol.
What I'm trying to do is create a simple Qt Android App that connects to the device and monitors the update. I've gotten as far as discovering the service and connecting it signal to it. I've done that using this code:
void BLETest::on_stateChanged(QLowEnergyService::ServiceState state){
Q_UNUSED(state);
// Only printing data if all services are in correct state.
for (qint32 i = 0; i < monitoredServices.size(); i++){
if (monitoredServices.at(i)->state() != QLowEnergyService::ServiceDiscovered){
logger->out("There are still services that have not been discoverd",Logger::LC_ORANGE);
return;
}
}
QString msg = "PRINTING SERVICE DATA<br>";
for (qint32 i = 0; i < monitoredServices.size(); i++){
QLowEnergyService *monitoredService = monitoredServices.at(i);
QList<QLowEnergyCharacteristic> clist = monitoredService->characteristics();
msg = msg + "SERVICE: " + monitoredService->serviceName() + ". UUID: " + monitoredService->serviceUuid().toString() + "<br>";
// Checking if this is the service that need connection.
if (monitoredService->serviceUuid() == QBluetoothUuid(QString("0a464eef-af72-43fd-8a8b-1f26f6319dab"))){
QString res;
if (connect(monitoredService,SIGNAL(characteristicChanged(QLowEnergyCharacteristic,QByteArray)),this,SLOT(on_charastericChanged(QLowEnergyCharacteristic,QByteArray)))) res = "true";
else res = "false";
logger->out("CONNECTED TO TARGET SERVICE: " + res,Logger::LC_ORANGE);
}
for (int i = 0; i < clist.size(); i++){
QString name = clist.at(i).name();
if (name.isEmpty()) name = "UNDEFINED NAME";
QByteArray buffer = clist.at(i).value();
//QString value = QString(clist.at(i).value());
QString value = QByteArray(buffer.toHex()) + " (BS = " + QString::number(buffer.size()) + ")";
QString properties = QString::number(clist.at(i).properties());
msg = msg + "CHARACTERISTIC: " + clist.at(i).uuid().toString() + " - " + name + ": " + value + ". PROPERTIES: " + properties + "<br>";
}
if (clist.isEmpty()){
msg = msg + "No characteristics found<br>";
}
}
logger->out(msg);
}
The above functions waits for all services to be discovered then prints the UUID, name and Value for all characteristics of all services. When the service I want to monitored is processed a connection is done to the changedCharacteristic signal.
When I do this the printed value of the characteristic of the service I want to monitor is the original value for that characteristic. However as that value updates I'm not notified (the signal never triggers) and so the value never changes in my app.
Do I need to write some code to actually trigger the signals?
PD: Using the Blue Gecko Demo App I can see the values changing.
EDIT: I decided to use a timer to Poll the value of the characteristic and it never changes. Which might indicate why the signal is never generated either.

You should connect a chracteristic changed handler to the service:
connect(service, SIGNAL(characteristicChanged(QLowEnergyCharacteristic, QByteArray)), this, SLOT(on_characteristicChanged(QLowEnergyCharacteristic, QByteArray)));
In the slot you can explore the data array.
However, the signal (characteristicChanged()) will only emitted by the service if the for this chracteristic notification is enabled. This works only, if the characteritic has a notify property, that should the case in your application.

Not cheatable Google fit step counter

i have a question to Google Fit.
I am creating a step counter (oh wonder g). This i have already done so far and it not really hard.
But now we come to my problem. I am only reading the steps with the Sensor API. The issue is, i can add new data via for example the Google Fit app and it will be counted in my app too. This introduces cheating and i do not want this.
So i need to have a way to only read "device created" data and not manually added data. Is there a nice way to to this?
From the SDK documentation it is not really clear how to proceed here.

So i need to have a way to only read "device created" data and not
manually added data. Is there a nice way to to this?
You will want to use Private Custom Data Types to achieve that. Read about the different types of Fitness data you can upload to Google Fit here.
1. Public data types
Standard data types provided by the platform, like com.google.step_count.delta. Any app can read and write data of
these types. For more information, see Public Data Types.
2. Private custom data types
Custom data types defined by an specific app. Only the app that defines the data type can read and write data
of this type. For more information, see Custom Data Types.
3. Shareable data types
Custom data types submitted to the platform by an app developer. Once approved, any app can read data of a
shareable type, but only whitelisted apps as specified by the
developer can write data of that shareable type. For more information,
see Shareable Data Types.

I was able to do this with the help of this alogrithm. But remember due to Android fragmentation this code still removes some of the user's data and count it as penalty
private String dumpDataSet(DataSet dataSet, int x) {
List<String> days = new ArrayList<>();
days.add("Monday");
days.add("Tuesday");
days.add("Wednesday");
days.add("Thursday");
days.add("Friday");
days.add("Saturday");
days.add("Sunday");
String day = days.get(Math.round(x / 24));
Log.d(TAG, "\tDay: " + day);
Log.i(TAG, "Data returned for Data type: " + dataSet.getDataType().getName());
DateFormat dateFormat = getTimeInstance();
String text = "";
try {
for (DataPoint dp : dataSet.getDataPoints()) {
Log.i(TAG, "\tStepCount getStreamName: " + dp.getOriginalDataSource().getStreamName());
Log.i(TAG, "\tStepCount getStreamIdentifier: " + dp.getOriginalDataSource().getStreamIdentifier());
Log.i(TAG, "\tStepCount App Type: " + dp.getDataType().getName());
Log.i(TAG, "\tStepCount Type: " + dp.getOriginalDataSource().getType());
for (Field field : dp.getDataType().getFields()) {
Log.i(TAG, "\tField: " + field.getName() + " Value: " + dp.getValue(field));
text += dp.getValue(field);
String si[] = dp.getOriginalDataSource().getStreamIdentifier().toLowerCase().split(":");
if ((((si[si.length - 1].contains("soft")) || (si[si.length - 1].contains("step"))) && si[si.length - 1].contains("counter"))) {
totalSteps += Integer.parseInt(dp.getValue(field).toString());
Log.d(TAG, "\tStepCount" + " Added Steps -> " + dp.getValue(field) + " steps");
text += "\n\n";
} else {
Log.e(TAG, "\tStepCount PENALTY ---------------------------------------------------------------");
Log.e(TAG, "\tDay = " + day + " | Hour Number = " + x + " | StepCount" + " PENALTY DEDUCTED -> " + dp.getValue(field) + " steps");
Log.e(TAG, "\tStepCount PENALTY getStreamIdentifier: " + dp.getOriginalDataSource().getStreamIdentifier());
Log.e(TAG, "\tStepCount PENALTY getStreamName: " + dp.getOriginalDataSource().getStreamName());
Log.e(TAG, "\tStepCount PENALTY App Type: " + dp.getDataType().getName());
Log.e(TAG, "\tStepCount PENALTY Type: " + dp.getOriginalDataSource().getType());
Log.e(TAG, "\tStepCount PENALTY ---------------------------------------------------------------");
}
}
}
} catch (Exception ex) {
ex.getStackTrace();
}
return text;
}
----- UPDATE -----
You can also call
DataPoint.getOriginalDataSource().getAppPackageName()
to filter out smartwatches and other apps.

I tried as suggested by Ali Shah lakhani but
DataPoint.getOriginalDataSource().getAppPackageName();
/*I also tried but could not achieve what I wanted*/
DataPoint.getOriginalDataSource().getStreamName();
DataPoint.getOriginalDataSource().getStreamIdentifier();
did not work at least for me while retrieving data. I ended up using readDailyTotalFromLocalDevice() as shown below in order to capture steps captured by device only.
Fitness.HistoryApi.readDailyTotalFromLocalDevice(mApiClient, DataType.TYPE_STEP_COUNT_DELTA).await(1, TimeUnit.MINUTES)
I cross checked the same with some of the apps that avoids manual entries in their app and the count provided by the function above is exactly the same.
Note: If a user is having multiple devices and is using the app on all of them, readDailyTotalFromLocalDevice() will have different value for each and every device since the function is responsible for returning device specific data only.

android - inserting to a google spreadsheet faster

I have an android app which writes to a google spreadsheet using the sheets API.
I am writing to a specific column, for example - 4
here is the code of the writing:
URL practiceToUpdateFeedUrl = null;
CellFeed practiceToUpdateCellFeed = null;
int ROWS_NUMBER = 20;
practiceToUpdateFeedUrl = new URI(worksheet.getCellFeedUrl()
.toString() + "?min-col=4&max-col=4").toURL();
practiceToUpdateCellFeed = service.getFeed(practiceToUpdateFeedUrl,
cellFeed.class);
// inserting to the column the text
for (int i = 0; i < ROWS_NUMBER ; i++) {
newEntry = new CellEntry(i + 1, 4, "insert to cell number" + (i+1));
service.insert(practiceToUpdateFeedUrl, newEntry);
}
My question is - is there a faster way to do this?
In this way I make about 20 calls to the API, is there a faster way?
thanks in advance

I have successfully entered data into a google spreadsheet from a hybrid (Phonegap-based) Android and iOS app by just doing an AJAX POST. Check out this blog post, might be what you are looking for.

using if statement in eclipse

i am trying to develop an app that scans the existing WiFi signal surrounded my deceive and if specific WiFi signal is existed, the program will do specific instructions as follows in the program bellow :
for (ScanResult result: results) {
int strength1 = info.getRssi ();
float strength_in_pre11=2*(strength1+100);
float Distance1 =30*(1-(strength_in_pre11/100));
tv = (TextView) findViewById (R.id.textView1);
if (result.SSID.equals("WiFi1")) {
String text="We are connecting to "+SSID+" Distance:"+Distance1+" " ;
tv.setText (text);
}
else {
String otherwifi1="The existing network is:\n\n";
otherwifi1+=result.SSID+":"+result.level+"\n\n";
otherwifi1+=result.SSID+":"+result.level+":"+Distance1+"\n";
tv.setText (otherwifi1);
}
}
well , the if statement is not satisfied even though the router name that i put in the if statement (WiFi1) is existed , only else condition is satisfied ?!
anyone can help
thank you

Check what's the value of result.SSID :
System.out.println(result.SSID.toString());
if (result.SSID.toString().equals("WiFi1")) {
String text="We are connecting to "+SSID+" Distance:"+Distance1+" " ;
tv.setText (text);
}

Can you try and put a log or syso to see what the ssid is ? and whether it has whitespaces or quotes around the actual name?
i current did something similar and i had to change my if to the following as the ssids i encountered had quotes
if (result.SSID.equals('"' + "WiFi1" + '"'))

SpannableStringBuffer limited to 9,999 characters?

My app reads in large amounts of data from text files assets and displays them on-screen in a TextView. (The largest is ~450k.) I read the file in, line-by-line into a SpannableStringBuffer (since there is some metadata I remove, such as section names). This approach has worked without complaints in the two years that I've had the app on the market (over 7k active device installs), so I know that the code is reasonably correct.
However, I got a recent report from a user on a LG Lucid (LGE VS840 4G, Android 2.3.6) that the text is truncated. From log entries, my app only got 9,999 characters in the buffer. Is this a known issue with a SpannableStringBuffer? Are there other recommended ways to build a large Spannable buffer? Any suggested workarounds?
Other than keeping a separate expected length that I update each time I append to the SpannableStringBuilder, I don't even have a good way to detect the error, since the append interface returns the object, not an error!
My code that reads in the data is:
currentOffset = 0;
try {
InputStream is = getAssets().open(filename);
BufferedReader br = new BufferedReader(new InputStreamReader(is));
ssb.clear();
jumpOffsets.clear();
ArrayList<String> sectionNamesList = new ArrayList<String>();
sectionOffsets.clear();
int offset = 0;
while (br.ready()) {
String s = br.readLine();
if (s.length() == 0) {
ssb.append("\n");
++offset;
} else if (s.charAt(0) == '\013') {
jumpOffsets.add(offset);
String name = s.substring(1);
if (name.length() > 0) {
sectionNamesList.add(name);
sectionOffsets.add(offset);
if (showSectionNames) {
ssb.append(name);
ssb.append("\n");
offset += name.length() + 1;
}
}
} else {
if (!showNikud) {
// Remove nikud based on Unicode character ranges
// Does not replace combined characters (\ufb20-\ufb4f)
// See
// http://en.wikipedia.org/wiki/Unicode_and_HTML_for_the_Hebrew_alphabet
s = s. replaceAll("[\u05b0-\u05c7]", "");
}
if (!showMeteg) {
// Remove meteg based on Unicode character ranges
// Does not replace combined characters (\ufb20-\ufb4f)
// See
// http://en.wikipedia.org/wiki/Unicode_and_HTML_for_the_Hebrew_alphabet
s = s.replaceAll("\u05bd", "");
}
ssb.append(s);
ssb.append("\n");
offset += s.length() + 1;
}
}
sectionNames = sectionNamesList.toArray(new String[0]);
currentFilename = filename;
Log.v(TAG, "ssb.length()=" + ssb.length() +
", daavenText.getText().length()=" +
daavenText.getText().length() +
", showNikud=" + showNikud +
", showMeteg=" + showMeteg +
", showSectionNames=" + showSectionNames +
", currentFilename=" + currentFilename
);
After looking over the interface, I plan to replace the showNikud and showMeteg cases with InputFilters.

Is this a known issue with a SpannableStringBuffer?
I see nothing in the source code to suggest a hard limit on the size of a SpannableStringBuffer. Given your experiences, my guess is that this is a problem particular to that device, due to a stupid decision by an engineer at the device manufacturer.
Any suggested workarounds?
If you are distributing through the Google Play Store, block this device in your console.
Or, don't use one massive TextView, but instead use several smaller TextView widgets in a ListView (so they can be recycled), perhaps one per paragraph. This should have the added benefit of reducing your memory footprint.
Or, generate HTML and display the content in a WebView.

After writing (and having the user run) a test app, it appears that his device has this arbitrary limit for SpannableStringBuilder, but not StringBuilder or StringBuffer. I tested a quick change to read into a StringBuilder and then create a SpannableString from the result. Unfortunately, that means that I can't create the spans until it is fully read in.
I have to consider using multiple TextView objects in a ListView, as well as using Html.FromHtml to see if that works better for my app's long term plans.