Develop Reference

How to get every time messages from service to activity using runOnUiThread

I have been stuck with one problem. I need some people which check a part of my code and help me with problem and critize my code (I write code but I haven't people which can say this is wrong or something in this pattern)
Generally.
My service get message from bluetooth (HC-05) and I can see values in Log.d, in service.
A part code of my service which get message.
private class ConnectedThread extends Thread{
private final BluetoothSocket bluetoothSocket;
private final InputStream inputStream;
private final OutputStream outputStream;
public ConnectedThread(BluetoothSocket socket){
Log.d(TAG,"ConnectedThread: Starting");
bluetoothSocket=socket;
InputStream tmpInput = null;
OutputStream tmpOutput = null;
try{
tmpInput = bluetoothSocket.getInputStream();
tmpOutput = bluetoothSocket.getOutputStream();
}catch (IOException e){
e.printStackTrace();
active=false;
}
inputStream=tmpInput;
outputStream=tmpOutput;
}
#Override
public void run() {
byte[] buffer = new byte[1024];
int bytes;
while(active){
try {
bytes = inputStream.read(buffer);
final String comingMsg = new String(buffer,0,bytes);
Log.d(TAG,"InputStream: " + comingMsg);
new Handler(Looper.getMainLooper()).post(new Runnable() {
#Override
public void run() {
Message message = new Message();
message.obj = comingMsg;
message.what = 1; // I need it to prevent NullObjReference
Log.d(TAG,"Handler run(): " + message.obj);
mHandler.sendMessage(message);
}
});
}catch (IOException e){
Log.e(TAG,"Write: Error reading input." + e.getMessage());
active=false;
break;
}
}
}
...some code is hidden because it is diploma thesis
}
The problem is get message every time from this service to another activity where all is happen.
I tried a lot of things (with Threads,Looper,runOnUiThread, handleMessage and callback), checked a lot of posts in stackoverflow and I tried to combine with my project but all time I had nullobjectreference (for that i tried to use msg.what to check) , black screen when tried to move to my home activity (it is main) and update my textView or typical crash app.
Now I want only to get message from service to textview. When everything starts working fine, I want to parse string (for example 3 first chars) and send message to one of six textviews.
A part of codes from onCreate before method runThread() is started:
Log.d(TAG,"Check intent - result");
if(getIntent().getIntExtra("result",0)==RESULT_OK){
mDevice = getIntent().getExtras().getParcelable("bonded device");
startConnection(mDevice,MY_UUID);
Log.d(TAG,"Check is active service ");
checkIfActive();;
}
Log.d(TAG,"Check intent - connect_to_paired");
if(getIntent().getIntExtra("connect_to_paired",0)==RESULT_OK){
mDevice = getIntent().getExtras().getParcelable("bonded_paired_device");
startConnection(mDevice,MY_UUID);
Log.d(TAG,"Check is active service ");
checkIfActive();
}
public void checkIfActive(){
Log.d(TAG,"CheckIfActive: Started");
while(myBluetoothService.active!=true) {
Log.d(TAG,"CheckIfActive() active is "+ myBluetoothService.active);
if (myBluetoothService.active) {
Log.d(TAG, "CheckIfActive: Running method runOnUiThread - myBluetoothService.active is "+myBluetoothService.active);
runThread();
}
}
}
Method runThread() which should work everytime after connected with bluetooth device:
public void runThread(){
//I used there Thread but when connection was fail,
// method created multiply threads when I tried to connect next time
runOnUiThread(new Runnable() {
#Override
public void run() {
handler = new Handler(Looper.getMainLooper()){
#Override
public void handleMessage(Message msg) {
while (true) {
switch (msg.what) {
//when is one, service has messages to send
case 1:
String message = myBluetoothService.mHandler.obtainMessage().toString();
rearLeft.setText(message);
break;
default:
super.handleMessage(msg);
}
}
}
};
}
});
}
UPDATE:
Is it good idea ? Maybe I can put JSON Object to service to send message and in the HomeActivity, I can try get values from JSON. Is it fast ? I send a lot of data, because bluetooth receive data of distance from 4 ultrasound sensors in 4 times in lasts until few milliseconds, everytime.
Here is screen how sees my data in service when I have debug logs.
Next idea, but still nothing:
HomeActivity (my main)
public void runThread(){
runOnUiThread(new Runnable() {
#Override
public void run() {
//Looper.prepare();
new Handler() {
#Override
public void handleMessage(Message msg) {
rearLeft.setText(msg.obj.toString());
}
};
//Looper.loop();
//Log.d(TAG, myBluetoothService.mHandler.getLooper().toString());
//rearLeft.setText(myBluetoothService.mHandler.getLooper().toString());
}
});
}
Service which should send data from bluetooth to UI Thread is the same (Check first code).
Screen from HomeActivity where you can see 6 text views. Now I want put all text to one view which will be refresh by get next message.

Ok this post a bit help me to solve problem:
Sending a simple message from Service to Activity
Maybe this link could help another people.
Thanks for help, now understand why i should use broadcast receiver to do this.

Issues communicating with UART header on Android Things Developer Preview 5 (RPI3)

I am attempting to communicate with a Pi header using Android Things Developer Preview 5. Below is the class I have created to communicate with the header as per the official Android Things documentation:
public class UartComm {
private static final String UART_DEVICE_NAME = "UART1";
private UartDevice mDevice;
private void configureUartFrame(UartDevice uart) throws IOException {
// Configure the UART port
uart.setBaudrate(115200);
}
public void onCreate() {
try {
PeripheralManagerService manager = new PeripheralManagerService();
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);
}
mDevice = manager.openUartDevice(UART_DEVICE_NAME);
configureUartFrame(mDevice);
mDevice.registerUartDeviceCallback(mUartCallback);
} catch (Exception e) {
Log.w(TAG, "Unable to access UART device", e);
}
}
public void readUartBuffer(UartDevice uart) throws IOException {
// Maximum amount of data to read at one time
final int maxCount = 40;
byte[] buffer = new byte[maxCount];
uart.read(buffer, maxCount);
String data = new String(buffer, "UTF-8");
Log.d(TAG, data);
}
private UartDeviceCallback mUartCallback = new UartDeviceCallback() {
#Override
public boolean onUartDeviceDataAvailable(UartDevice uart) {
// Read available data from the UART device
try {
readUartBuffer(uart);
} catch (IOException e) {
Log.w(TAG, "Unable to access UART device", e);
}
// Continue listening for more interrupts
return true;
}
#Override
public void onUartDeviceError(UartDevice uart, int error) {
Log.w(TAG, uart + ": Error event " + error);
}
};
}
In my MainActivity I create an instance of UartComm by doing UartComm device = new UartComm() and the proceed to call device.onCreate()
I have also modified /boot/cmdline.txt and removed the console=serial0,115200 and replaced it with console=tty0, I have also tried just removing the console line without adding console=tty0. In /boot/config.txt I have also removed enable_uart=1 and core-freq=400 and also added dtoverlay=pi3-miniuart-bt I have also tried to remove Bluetooth support altogether by doing dtoverlay=pi3-disable-bt to no avail.
I have tested that the header works and is configured correctly in Rapsbian, where I swapped /dev/ttyAMA0 and /dev/ttyS0 and it worked correctly. I was able to run the screen command on Raspbian with a default baud rate of 115200 and was able to get the desired information.
I would like to do the same in Android Things Developer Preview 5 and have the Bluetooth run over the mini-uart ttyS0 and the header run over ttyAMA0. My desired result is for the header to be accessible over UART0.
An older USB serial device that has the same functionality works, but I would prefer the UART device be physically on top of the Pi, so that is not an option.

Might be wrong but shouldn't:
private static final String UART_DEVICE_NAME = "UART1";
be UART0 i.e.
private static final String UART_DEVICE_NAME = "UART0";
I did a UART example here https://github.com/blundell/androidthings-uart/blob/master/app/src/main/java/com/blundell/tut/MainActivity.java (obviously different hardware) But it's connected to raspberry pi pins in the same way like so:

Connection refused when calling endpoints from android client

My android app uses google endpoints as a scalable backend solution. However, I am having trouble calling it from the android client.
I call an async task class from an activity and in the async task class call the endpoints method. In this case the default sayHi() method is called and the message should be displayed in a toast using the onPostExecute(String result) method.
However when I run the app module in the emulator, this error appears in the toast:
failed to connect to /10.0.2.2 (port 8080) after 20000ms: isConnected failed: ECONNREFUSED (Connection refused)
Here is the code that calls the async task from the activity:
Profile profile = new Profile(firstName, lastName, birthday);
new EndpointTask(). new SaveProfileTask(profile, this).execute();
Here is the async task class:
public class EndpointTask {
public class SaveProfileTask extends AsyncTask<Void, Void, String> {
private final String LOG_TAG = SaveProfileTask.class.getSimpleName();
private MyApi mApi;
private Profile mProfile;
private Context mContext;
public SaveProfileTask(Profile profile, Context context) {
mProfile = profile;
mContext = context;
}
#Override
protected String doInBackground(Void... params) {
if (mApi == null) {
MyApi.Builder builder = new MyApi.Builder(AndroidHttp.newCompatibleTransport(),
new AndroidJsonFactory(), null)
// options for running against local devappserver
// - 10.0.2.2 is localhost's IP address in Android emulator
// - turn off compression when running against local devappserver
.setRootUrl("http://10.0.2.2:8080/_ah/api/")
.setGoogleClientRequestInitializer(new GoogleClientRequestInitializer() {
#Override
public void initialize(AbstractGoogleClientRequest<?> abstractGoogleClientRequest) throws IOException {
abstractGoogleClientRequest.setDisableGZipContent(true);
}
});
mApi = builder.build();
}
try {
return mApi.sayHi(mProfile.getFirstName()).execute().getData();
} catch (IOException e) {
return e.getMessage();
}
}
#Override
protected void onPostExecute(String result) {
Toast.makeText(mContext, result, Toast.LENGTH_LONG).show();
Log.d(LOG_TAG, "ERROR: " + result);
}
}
}
Most of this is taken from the github repo here. Which is part of the official android documentation for hooking up the client with the backend for google app engine.
Why is this error occurring and how can it be fixed?
Thanks guys, happy coding.

Waiting for asynchronous I/O on Android

I have been trying for awhile to figure out an issue with Asynchronous i/o in an android application that I am working on.
This application is required to download data to from a series of tables from Microsoft Dynamics CRM.
Once the data has been down it must preform a series of operations on the data to fill out some forms.
My problem is that I must wait for the downloads to be complete in order to start the update process.
If I add a any form of wait to my code it seems that it blocks indefinitely and never executes the callback.
I have tried methods using AtomicBooleans, AtomicIntegers, and CountDownLatchs with no success.
Here is an example using an AtomicInteger.
final CountDownLatch latch = new CountDownLatch(1);
OrganizationServiceProxy orgService;
orgService = new OrganizationServiceProxy(Constant.ENDPOINT, CRMLogin.getRequestInterceptor());
ColumnSet columnSet = new ColumnSet();
columnSet.AddColumns(AccountEntry.FETCH_COLS);
orgService.Retrieve(AccountEntry.ENTITY, UUID.fromString(accountid), columnSet, new Callback<Entity>() {
#Override
public void success(Entity entity, Response response) {
Account account = new Account();
//Load the existing fields for the account
account.load(index);
String activityid = account.getValue(AccountEntry.ACTIVITY_ID);
String recordid = account.getValue(AccountEntry.RECORD_ID);
String name = account.getValue(AccountEntry.ACCOUNT_NAME);
//Overload the fields for the account
account.load(entity);
//Reset overloaded fields on the account.
account.setValue(AccountEntry.ACTIVITY_ID, activityid);
account.setValue(AccountEntry.RECORD_ID, recordid);
account.setValue(AccountEntry.ACCOUNT_NAME, name);
//overwrite the record in the database.
account.setValue(AccountEntry.SYNCED, "1");
account.update();
Log.d("pullAccount>>>", accountid + " " + "pulled.");
latch.countDown();
}
#Override
public void failure(RetrofitError error) {
Log.d("pullAccount>>>", accountid + " " + error.getMessage());
latch.countDown();
}
});
try{
latch.await(); //THIS BLOCKS FOREVER AND EVER
}
catch (Exception e){
}
Of note is the CallBack is implemented using Retrofit.
Any guidance would be greatly appreciated.
Thank you.

Look at AsyncTask it will handle what you want in a way that Android is optimized for. There is example usage here
http://developer.android.com/reference/android/os/AsyncTask.html
EDIT:
I kinda threw this together, let me know if it works as you would expect
public class AsyncOrganizationService extends AsyncTask<Void, Void, Entity> {
#Override
protected Entity doInBackground(Void... params) {
final CountDownLatch blocker = new CountDownLatch(1);
OrganizationServiceProxy orgService;
orgService = new OrganizationServiceProxy(Constant.ENDPOINT, CRMLogin.getRequestInterceptor());
ColumnSet columnSet = new ColumnSet();
columnSet.AddColumns(AccountEntry.FETCH_COLS);
final SettableFuture<Entity> result = SettableFuture.create();
orgService.Retrieve(AccountEntry.ENTITY, UUID.fromString(accountid), columnSet, new SortedList.Callback<Entity>() {
#Override
public void success(Entity entity, HttpHelper.Response response) {
result.set(entity);
blocker.countDown();
}
});
try {
blocker.await();
return result.get();
} catch (InterruptedException | ExecutionException e) {
throw new RuntimeException(e);
}
}
#Override
protected void onPostExecute(Entity entity) {
Account account = new Account();
//Load the existing fields for the account
account.load(index);
String activityid = account.getValue(AccountEntry.ACTIVITY_ID);
String recordid = account.getValue(AccountEntry.RECORD_ID);
String name = account.getValue(AccountEntry.ACCOUNT_NAME);
//Overload the fields for the account
account.load(entity);
//Reset overloaded fields on the account.
account.setValue(AccountEntry.ACTIVITY_ID, activityid);
account.setValue(AccountEntry.RECORD_ID, recordid);
account.setValue(AccountEntry.ACCOUNT_NAME, name);
//overwrite the record in the database.
account.setValue(AccountEntry.SYNCED, "1");
account.update();
Log.d("pullAccount>>>", accountid + " " + "pulled.");
}
Im using Guava's SettableFuture class (http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/util/concurrent/SettableFuture.html). Guava is quite an amazing library - if you're not using it you should consider doing so. Otherwise, you could whip something up really quick

Google Cloud Endpoints Setup Trouble

I'm completely new to Google's Cloud Platform and I'm having trouble setting it up for my Android device. I am attempting to follow this tutorial and I'm at the point of trying to test my backend with my Android Emulator. The emulator, however, gives me this message after 20 seconds, Where instead it should say my name. Here's my code so far:
MainActivity.java
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
buildUI();
new EndpointsAsyncTask().execute(new Pair<Context, String>(this, "Solomon"));
}
EndpointsAsyncTask.java
public class EndpointsAsyncTask extends AsyncTask<Pair<Context, String>, Void, String> {
private static MyApi myApiService = null;
private Context context;
#Override
protected String doInBackground(Pair<Context, String>... params) {
if(myApiService == null) { // Only do this once
MyApi.Builder builder = new MyApi.Builder(AndroidHttp.newCompatibleTransport(),
new AndroidJsonFactory(), null)
// options for running against local devappserver
// - 10.0.2.2 is localhost's IP address in Android emulator
// - turn off compression when running against local devappserver
.setRootUrl("http://10.0.2.2:8080/_ah/api/")
.setGoogleClientRequestInitializer(new GoogleClientRequestInitializer() {
#Override
public void initialize(AbstractGoogleClientRequest<?> abstractGoogleClientRequest) throws IOException {
abstractGoogleClientRequest.setDisableGZipContent(true);
}
});
// end options for devappserver
myApiService = builder.build();
}
context = params[0].first;
String name = params[0].second;
try {
return myApiService.sayHi(name).execute().getData();
} catch (IOException e) {
return e.getMessage();
}
}
#Override
protected void onPostExecute(String result) {
Toast.makeText(context, result, Toast.LENGTH_LONG).show();
}
}
All Help is appreciated!
EDIT: Part of the problem was that I was running Endpoints Backend rather than the App Engine Servlet Backend. But now I'm now getting "connection refused" and I am running the App Engine Servlet Backend. Any Ideas?

After a tough few days, i found that the problem was that I needed to change my rootUrl from http://10.0.2.2:8080/_ah/api/ to my appspot domain. Now I'm getting the Hello World message.