I have android platform on one end and arduino on the other, connected via serial. Everything works fine, however in some cases arduino restarts itself and causes a flow of unknown characters while its restarting to the serial.
Here is a serial log while arduino is rebooting:
�z������"&O�Z&���B
���F ���cd�:{����t�>��+������2�~����. ���r���DD���^��.�.B�.��ڮ2t��Z:��,R��A�ڢr��Ckˡ���.-���N^���b�����^���
Question is, how can I check on android end if the response was malformed?
You should probably add some kind of "framing" to your messages. CR/LF isn't enough.
For example, put a special "preamble" at the front, and watch for it on the Android side. Choose something that will not occur in the body ("payload") of the message. And choose something that is very unlikely to occur in the random chars that show up on a reboot, a couple of chars long.
You could also put a CRC at the end. "Fletcher" is easy.
I ended up using simple solution like this:
private String filterData(String receivedStr) {
if (receivedStr.contains(RECV_HEADER) && receivedStr.contains(mReadRules.RECV_END)) {
int header_pos = receivedStr.indexOf(RECV_HEADER);
int crc_pos = receivedStr.indexOf(RECV_END);
return receivedStr.substring(header_pos, crc_pos);
} else {
return null;
}
}
It also extracts message if its wrapped around with malformed data.
Related
With this setup, I've been able to get two android phones to send and receive UDP broadcasts. I can also use this setup to send a UDP broadcast from a physical Android device to an iPhone.
However, my problem is that it doesn't seem to work the other way around. The send function is ran on the iPhone, and the receive function is being run on the Android phone. The Android phone never gets the broadcast. It seems like something is wrong with the iPhone's sending function. Here's the setup:
The Android side that has worked for me before:
const port = 37069;
const address = '224.0.0.1';
void receive() async {
final socket = await RawDatagramSocket.bind(address, port);
socket.multicastHops = 1;
socket.broadcastEnabled = true;
socket.writeEventsEnabled = true;
socket.listen((RawSocketEvent event) {
print("still listening...");
final packet = socket.receive();
print("The packet was $packet");
print("It came from ${packet?.address}");
});
}
and this is the iPhone side, that seems to be the problem. I'm not getting errors, so I'm wondering if there are any permissions in the Info.plist file that need to be added?
void broadcast() {
// for the iphone
RawDatagramSocket.bind(address, port).then((RawDatagramSocket socket) {
socket.multicastLoopback = false;
socket.broadcastEnabled = true;
socket.readEventsEnabled = true;
for (int i = 0; i < 150; i++) {
socket.send("Sent #$i".codeUnits, InternetAddress(address), port);
print("sent $i");
}
socket.close();
});
}
I've tested this same setup in my project, and it has worked in the following situations:
Android -> Android
Android -> iOS
but, iOS -> Android doesn't work. When I run the app, I can see that the iPhone is indeed sending the data, but the Android isn't receiving anything. Is the Android side the problem? What am I doing wrong?
I ended up using a package called Bonsoir to achieve what I wanted to.
It lets you broadcast and receive network services, and I'm pretty sure its the same underlying technology as household programs like Airplay and Google Casting. It's also very reliable and simple to use.
To send a certain string, I passed in a string argument in the form of a dictionary into the attributes attribute within the BonsoirService class.
The package can be found here.
I am trying to receive the scanned barcode result from a device paired via (Bluetooth/USB) to an android device.
so many topics said :
most plug-in barcode scanners (that I've seen) are made as HID profile devices so whatever they are plugged into should see them as a Keyboard basically.
source
So I am using this code to receive the result of the scan:
#Override
public boolean dispatchKeyEvent(KeyEvent event) {
if (viewModel.onTriggerScan()) {
//1
char pressedKey = (char) event.getUnicodeChar();
viewModel.addCharToCode(pressedKey);
//2
String fullCode = event.getCharacters();
viewModel.fullCode(fullCode);
//check if the scan is done, received all the chars
if (event.getAction() == EditorInfo.IME_ACTION_DONE) {
//does this work ?
viewModel.gotAllChars();
//3
String fullCode2 = event.getCharacters();
viewModel.fullCode(fullCode2);
}
return true;
} else
return super.dispatchKeyEvent(event);
}
Note: I don't have a barcode scanner device for the test.
which code will receive the result ?? (1 or 2 or 3 ?)
You won't ever see an IME_ACTION_DONE, that's something that's Android only and an external keyboard would never generate.
After that, it's really up to how the scanner works. You may get a full key up and key down for each character. You may not, and may receive multiple characters per event. You may see it finish with a terminator (like \n) you may not- depends on how the scanner is configured. Unless you can configure it yourself or tell the user how to configure it, you need to be prepared for either (which means treating the data as done either after seeing the terminator, or after a second or two once new data stops coming in.
Really you need to buy a configurable scanner model and try it in multiple modes and make ever mode works. Expect it to take a few days in your schedule.
Workaround solution but it works 100%.
the solution is based on clone edittext (hidden from the UI), this edit text just receives the result on it, adds a listener, and when the result arrives gets it and clears the edittext field. An important step, when you try to receive the result(trigger scan) make sure that edittext has the focus otherwise you wil not get the result.
Quick steps:
1- create editText (any text field that receives inputs) in your layout
2- set its visibility to "gone" and clear it.
3- add onValueChangeListener to your edittext.
4- focus your edittext when you start trigger the scan
5- each time you the listener call, get the result and clear edittext
Note: never miss to focus your edittext whenever you start trigger scan.
Note: this method work(99%) for all external scan device and any barcode type.
I've got an app which connect itself programatically to a wifi connection. My problem is, I want to handle the case, that the password is wrong. I want to detect that the password is not correct in runtime. To be precise I've got a progressdialog running while the connection is established, so if the password is wrong the progressdialog is just shown all the time and can't be skipped. A further note: I handled a password which is less than 8 characters by using this code:
if(!m_wifiManager.enableNetwork(netId, true)) {
progressDialogConnecting.dismiss();
createInfoMessageDialog(CONST.WIFI_CON_FAILED_TITLE, CONST.WIFI_CON_FAILED_MSG_CONFAILURE);
m_wifiManager.reconnect();
return;
}
If the key for the wifi connection is less than 8 characters, this if-case gets triggered. But if it is longer than 8 characters and wrong I get an endless state of showing the progress dialog.
What I exactly want to ask: how do I handle 1. wrong password 2. connection states (just like Android system showing me the toasts "Connected to Wifi xyz") ? AND is it even possible to handel the first one (wrong password)?
Here is the code, that did not work for handling connection established event (this is just the wifirecevier, I also registered it in the activity):
public class WifiReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals(WifiManager.SUPPLICANT_CONNECTION_CHANGE_ACTION)) {
if (intent.getBooleanExtra(WifiManager.EXTRA_SUPPLICANT_CONNECTED, false)){
if(wrongNetworkConnected)
progressDialogConnecting.dismiss();
}
}
} else {
}
}
}
}
Edit: What I am currently doing, is that I have a Handler which tells me to whom I am connected. That's useful because I can say that after the reconnect() I am reconnected to the old network (current network) and not the new one - so apparently the password could be wrong (or something else), because I could not connect to the new network.
The problem about this method is that first of all it takes too much time and secondly it is not reliable. I can lie and say that if you will get reconnected to your current network it is the fault of a wrong password, but actually it is not 100% sure that you cannot reconnect because of this - it may also have other reasons. So I am still searching for a simple feedback/handle from the suplicant that the password is wrong, just like the android api does in the wifi settings of each android device...
My problem is, I want to handle the case, that the password is wrong.
After some research I found this post which is not marked as answered but it still worked for me very well.
Here is the if-case in which the program jumps (already tested several times by me) if there is an authentication error --> e.g. wrong password:
int supl_error=intent.getIntExtra(WifiManager.EXTRA_SUPPLICANT_ERROR, -1);
if(supl_error==WifiManager.ERROR_AUTHENTICATING){
// DO SOMETHING
}
NOTE: As seen in the linked post above this if-case should appear in a BroadcastReceiver adding the intent WifiManager.SUPPLICANT_STATE_CHANGED_ACTIONto the receiver-registration in your activity-class.
I am trying to add a few commands to android default voicedialer app. It has commands like Open, dial, call, redial etc, I want to include lets say 'Find' to it. I have downloaded the source code from here and compiled it in Eclipse. the application sets up Grammar for arguments of these commands like it stores the names and phone numbers of the persons in contact list to generate intents when their names are recognized for CALL JOHN voice command. For CALL in this command it is just comparing the first word of resulting recognized string to "CALL".
I added "FIND" as an extra else if condition in the onRecognitionSuccess() function as shown below:
public class CommandRecognizerEngine extends RecognizerEngine
{
............
protected void onRecognitionSuccess(RecognizerClient recognizerClient) throws InterruptedException
{
.....................
if ("DIAL".equalsIgnoreCase(commands[0]))
{
Uri uri = Uri.fromParts("tel", commands[1], null);
String num = formatNumber(commands[1]);
if (num != null)
{
addCallIntent(intents, uri, literal.split(" ")[0].trim() + " " + num, "", 0);
}
}
................
else if ("FIND".equalsIgnoreCase(commands[0]))
{
if (Config.LOGD)
Log.d(TAG, "FIND detected...");
}
}//end onRecognitionSuccess
}//end CommandRecognizerEngine
but my app can't recognize it. Does anyone know how does recognizer detects commands like OPEN or CALL etc or refer me to appropriate documentation?
Thanks.
As it has been over a year, I doubt you need this answer anymore. However, some other people might find this through Google, as I did.
Right now, the best way to apply grammars to speech recognition on Android is to set the number of results higher, and then filter the results based on your grammar. It is not perfect, as the word recognized may not have passed a threshold to be included in the list, but it does greatly improve the accuracy of all speech recognition applications where the types of things you can say are somewhat limited.
I have a app, which sends a lot of SMS messages to a central server. Each user will probably send ~300 txts/day. SMS messages are being used as a networking layer, because SMS is almost everywhere and mobile internet is not. The app is intended for use in a lot of 3rd world countries where mobile internet is not ubiquitous.
When I hit a limit of 100 messages, I get a prompt for each message sent. The prompt says "A large number of SMS messages are being sent". This is not ok for the user to get prompted each time to ask if the app can send a text message. The user doesn't want to get 30 consecutive prompts.
I found this android source file with google. It could be out of date, I can't tell. It looks like there is a limit of 100 sms messages every 3600000ms(1 day) for each application.
http://www.netmite.com/android/mydroid/frameworks/base/telephony/java/com/android/internal/telephony/gsm/SMSDispatcher.java
/** Default checking period for SMS sent without uesr permit */
private static final int DEFAULT_SMS_CHECK_PERIOD = 3600000;
/** Default number of SMS sent in checking period without uesr permit */
private static final int DEFAULT_SMS_MAX_ALLOWED = 100;
and
/**
* Implement the per-application based SMS control, which only allows
* a limit on the number of SMS/MMS messages an app can send in checking
* period.
*/
private class SmsCounter {
private int mCheckPeriod;
private int mMaxAllowed;
private HashMap<String, ArrayList<Long>> mSmsStamp;
/**
* Create SmsCounter
* #param mMax is the number of SMS allowed without user permit
* #param mPeriod is the checking period
*/
SmsCounter(int mMax, int mPeriod) {
mMaxAllowed = mMax;
mCheckPeriod = mPeriod;
mSmsStamp = new HashMap<String, ArrayList<Long>> ();
}
boolean check(String appName) {
if (!mSmsStamp.containsKey(appName)) {
mSmsStamp.put(appName, new ArrayList<Long>());
}
return isUnderLimit(mSmsStamp.get(appName));
}
private boolean isUnderLimit(ArrayList<Long> sent) {
Long ct = System.currentTimeMillis();
Log.d(TAG, "SMS send size=" + sent.size() + "time=" + ct);
while (sent.size() > 0 && (ct - sent.get(0)) > mCheckPeriod ) {
sent.remove(0);
}
if (sent.size() < mMaxAllowed) {
sent.add(ct);
return true;
}
return false;
}
}
Is this even the real android code? It looks like it is in the package "com.android.internal.telephony.gsm", I can't find this package on the android website.
How can I disable/modify this limit? I've been googling for solutions, but I haven't found anything.
So I was looking at the link that commonsware.com posted, and I found that the source had actually changed. And so I might still have a shot.
int check_period = Settings.Gservices.getInt(mResolver,
Settings.Gservices.SMS_OUTGOING_CEHCK_INTERVAL_MS,
DEFAULT_SMS_CHECK_PERIOD);
int max_count = Settings.Gservices.getInt(mResolver,
Settings.Gservices.SMS_OUTGOING_CEHCK_MAX_COUNT,
DEFAULT_SMS_MAX_COUNT);
mCounter = new SmsCounter(max_count, check_period);
This is getting checkPeriod and maxCount from a settings table. But I don't seem to have access to the same table. That source should be Android 1.1, which is the same I'm using. When I try to import android.provider.Settings.Gservices, I get an error saying that the import can't be resolved.
What is going on?
Did you try using "import android.provider.Settings;" instead of "import android.provider.Settings.GServices"? (see line 36 of SMSDispatcher.java)
Also, not sure how much difference it makes, but 3600000 ms is one hour not one day.
Unfortunately I think you only have a few options
1) Get root access and alter the settings table directly by doing:
sqlite3 /data/data/com.android.providers.settings/databases/settings.db
sqlite> INSERT INTO gservices (name, value) VALUES
('sms_outgoing_check_interval_ms', 0);
2) Use multiple apps since it's a per app limit
3) Perhaps take out the battery after you reach the limit? It looks like the limit is stored in memory. I haven't tried this yet though.
This appears to be built into the Android source tree, so the only way to push this change down to the users would be the build your own ROM and have them install it.
As for ideas on getting around it, why not check for network connectivity first rather than just assuming it doesn't exist. Even if it is not present on a significant majority of devices today, that certainly won't always be the case. Let SMS be the fall back mechanism. If it is the fall back mechanism, you can then prompt the user letting them know that they will be prompted to confirm the level of SMS activity every 100 messages or so. Who knows, they may roam into a Wifi hotspot and have connectivity part of the day too.
Otherwise, you will get into a game of installing a bunch of other Activities+Intents that can act as silent SMS proxies to get around the limit. Of course, this has its own certain set of undesirable qualities as well and I can hardly believe I just typed/suggested something that evil.