Develop Reference

AndroidThings UsbToUart cannot Rx data when run long times [close]

Hello I use android thing on raspberry pi 3, I have a problem my app use UsbToSerial and then my app can Tx but cannot Rx data when app run longtime but in first period of work my app can Rx data and app can Tx alway times
How can I fix the problem?
And this is my code
MainActivity.java
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
UartService uart_api = new UartService();
uart_api.UartInit("USB1-1.2:1.0", 9600);
}
UartService.java
public class UartService extends Activity {
private static final String TAG = "LoopbackActivity";
// UART Configuration Parameters
private static final int DATA_BITS = 8;
private static final int STOP_BITS = 1;
private static final int CHUNK_SIZE = 512;
private UartDevice mLoopbackDevice;
private void openUart(String name, int baudRate) throws IOException {
mLoopbackDevice = PeripheralManager.getInstance().openUartDevice(name);
// Configure the UART
mLoopbackDevice.setBaudrate(baudRate);
mLoopbackDevice.setDataSize(DATA_BITS);
mLoopbackDevice.setParity(UartDevice.PARITY_NONE);
mLoopbackDevice.setStopBits(STOP_BITS);
}
public void UartInit(String UartName, int baudrate){
PeripheralManager manager = PeripheralManager.getInstance();
List<String> deviceList = manager.getUartDeviceList();
if (deviceList.isEmpty()) {
Log.i(TAG, "No UART port available on this device.");
} else {
Log.i(TAG, "List of available devices: " + deviceList);
}
// Attempt to access the UART device
try {
openUart(UartName, baudrate);
// Read any initially buffered data
Thread thread_read = new Thread(new ThreadUart(123));
thread_read.start();
} catch (IOException e) {
Log.e(TAG, "Unable to open UART device", e);
}
}
public class ThreadUart implements Runnable {
private int data_in;
public ThreadUart(int in) {
this.data_in = in;
}
#Override
public void run() {
while(true){
///////// Test Rx //////
if (mLoopbackDevice != null) {
// Loop until there is no more data in the RX buffer.
try {
byte[] buffer = new byte[CHUNK_SIZE];
int read;
while ((read = mLoopbackDevice.read(buffer, buffer.length)) > 0) { // <<<< when run long time this cannot Rx data
mLoopbackDevice.write(buffer, read);
}
} catch (IOException e) {
Log.w(TAG, "Unable to transfer data over UART", e);
}
}
// sleep 1 sec.
///////// Test Tx //////
String string = "Hello\r\n";
byte[] b = string.getBytes(StandardCharsets.UTF_8);
try {
mLoopbackDevice.write(b, b.length); // <<<< can Tx work!! always time
} catch (IOException e) {
e.printStackTrace();
}
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}

finarly I follow Example example, It work !! in example use felHR85’s USBSerial library
however I don't know cause of Rx lost when use UART API and then run long time

NFC tag(for NfcA) scan works only from the second time

I wrote a custom plugin to read blocks of data from an NfcA(i.e.non-ndef) tag. It seems to work fine , but only after the second scan. I am using Activity intent to derive the "NfcAdapter.EXTRA_TAG" to later use it for reading the values. I am also updating the Intents in onNewIntent(). OnNewIntent gets called after the second scan and after that I get result all the time.But in the first scan onNewIntent does not gets called, hence I end up using the Activity tag that does not have "NfcAdapter.EXTRA_TAG", hence I get null. Please see the my code below.
SE_NfcA.java(my native code for plugin)
#Override
public boolean execute(String action, JSONArray args, CallbackContext callbackContext) throws JSONException {
String Result = "";
String TypeOfTalking = "";
if (action.contains("TalkToNFC"))
{
JSONObject arg_object = args.getJSONObject(0);
TypeOfTalking = arg_object.getString("type");
if(TypeOfTalking != "")
{
if (TypeOfTalking.contains("readBlock"))
{
if(TypeOfTalking.contains("#"))
{
try
{
String[] parts = TypeOfTalking.split("#");
int index = Integer.parseInt(parts[1]);
Result = Readblock(cordova.getActivity().getIntent(),(byte)index);
callbackContext.success(Result);
}
catch(Exception e)
{
callbackContext.error("Exception Reading "+ TypeOfTalking + "due to "+ e.toString());
return false;
}
}
}
else
{
return false;
}
}
else
{
return false;
}
}
else
{
return false;
}
return true;
}
#Override
public void onNewIntent(Intent intent) {
ShowAlert("onNewIntent called");
Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
super.onNewIntent(intent);
getActivity().setIntent(intent);
savedTag = tagFromIntent;
savedIntent = intent;
}
#Override
public void onPause(boolean multitasking) {
Log.d(TAG, "onPause " + getActivity().getIntent());
super.onPause(multitasking);
if (multitasking) {
// nfc can't run in background
stopNfc();
}
}
#Override
public void onResume(boolean multitasking) {
Log.d(TAG, "onResume " + getActivity().getIntent());
super.onResume(multitasking);
startNfc();
}
public String Readblock(Intent Intent,byte block) throws IOException{
byte[] response = new byte[]{};
if(Intent != null)
{
Tag myTag = Intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
if(savedTag != null)
myTag = savedTag;
if(myTag != null)
{
try{
Reader nTagReader = new Reader(myTag);
nTagReader.close();
nTagReader.connect();
nTagReader.SectorSelect(Sector.Sector0);
response = nTagReader.fast_read(block, block);
nTagReader.close();
return ConvertH(response);
}catch(Exception e){
ShowAlert(e.toString());
}
}
else
ShowAlert("myTag is null.");
}
return null;
}
private void createPendingIntent() {
if (pendingIntent == null) {
Activity activity = getActivity();
Intent intent = new Intent(activity, activity.getClass());
intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP| Intent.FLAG_ACTIVITY_CLEAR_TOP);
pendingIntent = PendingIntent.getActivity(activity, 0, intent, 0);
}
}
private void startNfc() {
createPendingIntent(); // onResume can call startNfc before execute
getActivity().runOnUiThread(new Runnable() {
public void run() {
NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(getActivity());
if (nfcAdapter != null && !getActivity().isFinishing()) {
try {
nfcAdapter.enableForegroundDispatch(getActivity(), getPendingIntent(), getIntentFilters(), getTechLists());
if (p2pMessage != null) {
nfcAdapter.setNdefPushMessage(p2pMessage, getActivity());
}
} catch (IllegalStateException e) {
// issue 110 - user exits app with home button while nfc is initializing
Log.w(TAG, "Illegal State Exception starting NFC. Assuming application is terminating.");
}
}
}
});
}
private void stopNfc() {
Log.d(TAG, "stopNfc");
getActivity().runOnUiThread(new Runnable() {
public void run() {
NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(getActivity());
if (nfcAdapter != null) {
try {
nfcAdapter.disableForegroundDispatch(getActivity());
} catch (IllegalStateException e) {
// issue 125 - user exits app with back button while nfc
Log.w(TAG, "Illegal State Exception stopping NFC. Assuming application is terminating.");
}
}
}
});
}
private Activity getActivity() {
return this.cordova.getActivity();
}
private PendingIntent getPendingIntent() {
return pendingIntent;
}
private IntentFilter[] getIntentFilters() {
return intentFilters.toArray(new IntentFilter[intentFilters.size()]);
}
private String[][] getTechLists() {
//noinspection ToArrayCallWithZeroLengthArrayArgument
return techLists.toArray(new String[0][0]);
}
}
My index.js file
nfc.addTagDiscoveredListener(
function(nfcEvent){
console.log(nfcEvent.tag.id);
alert(nfcEvent.tag.id);
window.echo("readBlock#88");//call to plugin
},
function() {
alert("Listening for NFC tags.");
},
function() {
alert("NFC activation failed.");
}
);
SE_NfcA.js(plugin interface for interaction b/w index.js and SE_NfcA.java)
window.echo = function(natureOfTalk)
{
alert("Inside JS Interface, arg =" + natureOfTalk);
cordova.exec(function(result){alert("Result is : "+result);},
function(error){alert("Some Error happened : "+ error);},
"SE_NfcA","TalkToNFC",[{"type": natureOfTalk}]);
};
I guess I have messed up with the Intents/Activity Life-Cycle, please help. TIA!

I found a tweak/hack and made it to work.
Before making any call to read or write, I made one dummy Initialize call.
window.echo("Initialize");
window.echo("readBlock#88");//call to plugin to read.
And in the native code of the plugin, on receiving the "Initialize" token I made a startNFC() call.
else if(TypeOfTalking.equalsIgnoreCase("Initialize"))
{
startNfc();
}

Access Expansion File Globally

I need to access a lot of images from the expansion file throughout a lot of activities.
Doing the:
expansionFile = APKExpansionSupport.getAPKExpansionZipFile(context, 8, -1);
fileStream = expansionFile.getInputStream("drawables/drawable-hdpi/" + image);
Drawable drawable = Drawable.createFromStream(fileStream, null);
for every activity is very slow, in some activities I need to load 4 ou more images at the same time.
So what do you think if I create a new class that abstracts this code in every activity?

So I created a class ExpansionFileRetriever, that retrieves the expansion file:
public class ExpansionFileRetriever{
private static ExpansionFileRetriever instance;
public static ExpansionFileRetriever get() {
if(instance == null) instance = getSync();
return instance;
}
private static synchronized ExpansionFileRetriever getSync() {
if(instance == null) instance = new ExpansionFileRetriever();
return instance;
}
public ExpansionFileRetriever(){
// here you can directly access the Application context calling
Context c = App.get();
try {
expansionFile = APKExpansionSupport.getAPKExpansionZipFile(c, 20, -1);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
ZipResourceFile expansionFile;
public Drawable getDrawable(String path, String resource) {
InputStream fileStream = null;
String file = path + resource;
try {
fileStream = expansionFile.getInputStream(file);
Drawable drawable = Drawable.createFromStream(fileStream, null);
return drawable;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
}
}
and whenever I need to access files for the expansion file
I just use
ExpansionFileRetriever expFile = ExpansionFileRetriever.get();
and to get, say a Drawable all I do is:
expFile.getDrawable(path, name)

Enable bluetooth tethering android programmatically

I am trying to make an application like "Bluetooth auto tethering" on play store. I read on the forum that Android is very security-aware and will not enable this setting without user interaction.
I need some explanations about how enable bluetooth tethering.
Thank you

I don't know if this is still an issue or not, but I found that using the connect method in the reflection call works. Working off of the code that pmont used from the link in Lorelorelore's answer:
BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Class<?> classBluetoothPan = null;
Constructor<?> BTPanCtor = null;
Object BTSrvInstance = null;
Method mBTPanConnect;
try {
classBluetoothPan = Class.forName("android.bluetooth.BluetoothPan");
mBTPanConnect = classBluetoothPan.getDeclaredMethod("connect", BluetoothDevice.class);
BTPanCtor = classBluetoothPan.getDeclaredConstructor(Context.class, BluetoothProfile.ServiceListener.class);
BTPanCtor.setAccessible(true);
BTSrvInstance = BTPanCtor.newInstance(myContext, new BTPanServiceListener(myContext));
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
// If there are paired devices
if (pairedDevices.size() > 0) {
// Loop through paired devices
for (BluetoothDevice device : pairedDevices) {
try{
mBTPanConnect.invoke(BTSrvInstance, device);
}
catch (Exception e) {
e.printStackTrace();
}
}
}
Of course, this assumes that the bluetooth is enabled, and you only have one paired device. But enabling bluetooth is pretty straightforward using standard (not reflection) calls, and you can just check for the paired device that you want to connect to in the for loop. Also, don't forget the BTPanServiceListener class from the other answer as well.
Hope this helps.

The solution above required some modification in order to work for me. Specifically, the code to enable tethering needs to be in the OnServiceConnected() method. Also I have the following permissions set in the manifest:
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"/>
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
Here is my solution:
public class BluetoothTethering extends ActionBarActivity {
Object instance = null;
Method setTetheringOn = null;
Method isTetheringOn = null;
Object mutex = new Object();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bluetooth_tethering);
String sClassName = "android.bluetooth.BluetoothPan";
try {
Class<?> classBluetoothPan = Class.forName(sClassName);
Constructor<?> ctor = classBluetoothPan.getDeclaredConstructor(Context.class, BluetoothProfile.ServiceListener.class);
ctor.setAccessible(true);
// Set Tethering ON
Class[] paramSet = new Class[1];
paramSet[0] = boolean.class;
synchronized (mutex) {
setTetheringOn = classBluetoothPan.getDeclaredMethod("setBluetoothTethering", paramSet);
isTetheringOn = classBluetoothPan.getDeclaredMethod("isTetheringOn", null);
instance = ctor.newInstance(getApplicationContext(), new BTPanServiceListener(getApplicationContext()));
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
public class BTPanServiceListener implements BluetoothProfile.ServiceListener {
private final Context context;
public BTPanServiceListener(final Context context) {
this.context = context;
}
#Override
public void onServiceConnected(final int profile,
final BluetoothProfile proxy) {
//Some code must be here or the compiler will optimize away this callback.
try {
synchronized (mutex) {
setTetheringOn.invoke(instance, true);
if ((Boolean)isTetheringOn.invoke(instance, null)) {
Toast.makeText(getApplicationContext(), "BT Tethering is on", Toast.LENGTH_LONG).show();
}
else {
Toast.makeText(getApplicationContext(), "BT Tethering is off", Toast.LENGTH_LONG).show();
}
}
}
catch (InvocationTargetException e) {
e.printStackTrace();
}
catch (IllegalAccessException e) {
e.printStackTrace();
}
}
#Override
public void onServiceDisconnected(final int profile) {
}
}
}

The below code works perfectly for me
String sClassName = "android.bluetooth.BluetoothPan";
try {
Class<?> classBluetoothPan = Class.forName(sClassName);
Constructor<?> ctor = classBluetoothPan.getDeclaredConstructor(Context.class, BluetoothProfile.ServiceListener.class);
ctor.setAccessible(true);
Object instance = ctor.newInstance(getApplicationContext(), new BTPanServiceListener(getApplicationContext()));
// Set Tethering ON
Class[] paramSet = new Class[1];
paramSet[0] = boolean.class;
Method setTetheringOn = classBluetoothPan.getDeclaredMethod("setBluetoothTethering", paramSet);
setTetheringOn.invoke(instance,true);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
public class BTPanServiceListener implements BluetoothProfile.ServiceListener {
private final Context context;
public BTPanServiceListener(final Context context) {
this.context = context;
}
#Override
public void onServiceConnected(final int profile,
final BluetoothProfile proxy) {
//Some code must be here or the compiler will optimize away this callback.
Log.e("MyApp", "BTPan proxy connected");
}
#Override
public void onServiceDisconnected(final int profile) {
}
}

Here you find a similar question: Bluetooth question
Just replace "isTetheringOn" with "setBluetoothTethering" in the reflection call and pass in a boolean parameter. It should work.

Android - Cannot make a static reference to a non static method

I refactoring my threads in order to avoid memory leaks, and I got 2 errors regarding handler and startActivityForResult being called from within the thread ( dealing with GoogleDrive)
I have in my DownloadActivity :
public class DownloadActivity extends Activity {
....
private void getFolderId(){
getFolderIdThread = new GetFolderIdThread();
getFolderIdThread.start();
}
private static class GetFolderIdThread extends Thread {
private Boolean mRunning = false;
#Override
public void run() {
mRunning = true;
fResultList = new ArrayList<File>();
Files f1 = mService.files();
Files.List request = null;
aFolderId = null;
do {
try {
request = f1.list();
String aQuery = "'root' in parents and mimeType='application/vnd.google-apps.folder' and title='"+ aFolderName + "'";
request.setQ(aQuery);
FileList fileList = request.execute();
fResultList.addAll(fileList.getItems());
request.setPageToken(fileList.getNextPageToken());
} catch (UserRecoverableAuthIOException e) {
startActivityForResult(e.getIntent(), REQUEST_AUTHORIZATION); <= THIS RAISES THE ERROR
} catch (IOException e) {
e.printStackTrace();
if (request != null){
request.setPageToken(null);
}
}
} while (request.getPageToken() !=null && request.getPageToken().length() > 0);
if (fResultList.size() == 0) {
Log.d(TAG, "cannot find the training folder at root level");
Message msg = handler.obtainMessage(); <= THIS RAISES THE ERROR
Bundle bundle = new Bundle();
bundle.putInt("msgKey", DownloadActivity.NO_TRAININGS_FOLDER);
msg.setData(bundle);
handler.sendMessage(msg); <= THIS RAISES THE ERROR
} else {
File folder = fResultList.get(0);
aFolderId = folder.getId();
getFolderContents(); <= THIS RAISES THE ERROR
}
}
public void close() {
mRunning = false;
}
}
I have the handler defined in my activity
Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
...
}
}
and the onActivityResult
protected void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
switch (requestCode) {
case REQUEST_ACCOUNT_PICKER:
....
break;
}
}
what are my options to bypass this error ?

Your GetFolderIdThread class is static and a static nested class cannot reference non-static methods and fields in the instance of the outer class that created it. Such a nested class can only access static methods and fields in your Activity. Remove static from the class definition and I think your problem will resolve.
You also need to post your call to startActivityForResult on the UI thread. Of course you should be able to use your handler for that, something like:
handler.post(new Runnable()
{
public void run()
{
startActivityForResult(e.getIntent(), REQUEST_AUTHORIZATION);
}
});
Make sure your thread can gracefully complete as well when you do that because it will continue to run.