I'm writing an Android app that communicates with a website. Any time I hit the website, I'm displaying a ProcessDialog so that the user knows something's happening. Most of my website communication is one-way, so I don't usually expect any return data.
There is one point however where I need to get information back, but the results are not being stored when I exit the child thread. In a nutshell, I need to call a thread, let it process the results, and store the results in a couple of fields.
Here's what I've got so far - I have two variables, String[] Account and boolean AccountRetrievalSuccess:
public void GetAccount() {
MyDialog = ProgressDialog.show( MyContext, "Retrieving Account" , "We're retrieving your account information. Please wait...", true);
Thread T = new GetAccountThread();
T.start();
}
public class GetAccountThread extends Thread {
#Override
public void run() {
try {
String resp = GetPage(BaseURL+MainPage+"?P="+PhoneID+"&K="+WebAccessKey+"&A=ACCOUNT");
if (resp.contains("FAILURE|")){
failhandler.sendEmptyMessage(0);
} else {
resp = resp.replace("SUCCESS|", "");
Account = resp.split("\\|");
handler.sendEmptyMessage(0);
}
} catch (Exception e) {
failhandler.sendEmptyMessage(0);
}
};
private Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
AccountRetrievalSuccess = true;
MyDialog.dismiss();
}
};
private Handler failhandler = new Handler() {
#Override
public void handleMessage(Message msg) {
AccountRetrievalSuccess = false;
MyDialog.dismiss();
ShowWtf();
}
};
}
Any idea what I'd need to do to be able to store the Account and AccountRetrievalSuccess values so that I can access them from elsewhere in the code?
Looks like a perfect job for AsyncTask!
This class allows you to run a task on a background thread and return the results back to the UI thread whilst reporting progress on the task at hand.
Not expecting a result in a mobile app might be a bad idea by the way, due to nature of mobile network connections you'd never know for sure if your server actually got the thing you sent it (and the server might have failed while processing and your app would never know...)
Do not use threads. You should use executors for that. Implement a Callable<> interface, create an ExecutorService and run it. Have a look to the java.util.concurrent package.
Make those global variables in the containing Activity and then pass them to the handler:
Message m = Message.obtain();
m.obj = Account;
handler.sendMessageDelayed(m, 1);
Then in the handler you can cast m.obj back to the Account type and its nice and available.
Scott.. You should not have more than one handler per activity. Instead switch on what. You can send data (or objects) in messages as in:
Message msg= Message.obtainMessage(0);
Bundle b= new Bundle();
b.putString("stringData",outString);
msg.setData(b);
handler.sendMessage(msg);
You can switch on multiple messages in the handler as in.
public void handleMessage(Message msg){
switch(msg.what){
case BUTTON_ONE_UP_SELECTED:
this.removeMessages(BUTTON_ONE_UP_SELECTED);
buttonLarger01.setImageResource(R.drawable.btn_zoom_up_selected);
break;
case BUTTON_ONE_UP_NORMAL:
this.removeMessages(BUTTON_ONE_UP_NORMAL);
buttonLarger01.setImageResource(R.drawable.btn_zoom_up_normal);
break;
case BUTTON_TWO_UP_SELECTED:
this.removeMessages(BUTTON_TWO_UP_SELECTED);
buttonLarger02.setImageResource(R.drawable.btn_zoom_up_selected);
break;
case BUTTON_TWO_UP_NORMAL:
this.removeMessages(BUTTON_TWO_UP_NORMAL);
buttonLarger02.setImageResource(R.drawable.btn_zoom_up_normal);
break;
case BUTTON_ONE_DOWN_SELECTED:
this.removeMessages(BUTTON_ONE_DOWN_SELECTED);
buttonSmaller01.setImageResource(R.drawable.btn_zoom_down_selected);
break;
case BUTTON_ONE_DOWN_NORMAL:
this.removeMessages(BUTTON_ONE_DOWN_NORMAL);
buttonSmaller01.setImageResource(R.drawable.btn_zoom_down_normal);
break;
case BUTTON_TWO_DOWN_SELECTED:
this.removeMessages(BUTTON_TWO_DOWN_SELECTED);
buttonSmaller02.setImageResource(R.drawable.btn_zoom_down_selected);
break;
case BUTTON_TWO_DOWN_NORMAL:
this.removeMessages(BUTTON_TWO_DOWN_NORMAL);
buttonSmaller02.setImageResource(R.drawable.btn_zoom_down_normal);
break;
default:
super.handleMessage(msg);
break;
}
}
};
So in your case you could define SUCCESS as what 0 and FAILURE as what 1 etc.
Related
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.
I have phone contact numbers list stored in an array and called contactsString[]
and in an online database registered users numbers
I want to count how many registered users are there
and there is my code
for (i=0;i<contactsString.length-1;i++){
Phone phone=new Phone();
phone.phone=contactsString[i]
WebService.getInstance().getApi().checkNumber(phone).enqueue(new Callback<MainResponse>() {
#Override
public void onResponse(Call<MainResponse> call, Response<MainResponse> response) {
if (response.body().status==1){
availableUsers++;
}
}
#Override
public void onFailure(Call<MainResponse> call, Throwable t) {
}
});
}
my problem is the web service response is delayed so it don't count and availableUsers is printed it's initial value which is 0
I would try better sending an array of Phone objects. In this way you would get the correct answer in 1 call.
I would never do this in the way you implemented: imagine you have 500 contacts: you will be doing 500 calls to your server. Now imagine you have 100000 users with 500 contacts each
Try to customize your api call in this format. Which uses async task class.
private void phoneContact() {
new AsyncTask<String,Void,String>() {
#Override
protected String doInBackground(String ... params) {
try {
Platform http = Url_Contacts;
JSONObject resp = http.search(what,where);
Log.d(TAG, "Response: " + resp.toString());
} catch (Exception e) {
Log.e(TAG, e.getMessage());
}
return "";
}
}.execute();
}
Make sure that your service works well and the format of json with value status in there.
In onResponse, run on UIThread to update your View with the availableUsers.
The enqueue method is asynchronous. So your code should respect the multithreaded nature of it.
There are many approaches you can take:
Replace enqueue() method with execute(). But that makes all the calls synchronous. If you call it in UI Thread then whole app can stutter. Probably you will get NetworkOnMainThreadException. Not a good approach anyway.
Use RxAndroid or RxJava with Observer pattern.
Simple solution. Create a variable int callsFinished = 0;. In onResponse increment that variable. Then if that callsFinished == contactsString.length that means all calls have been done.
In your activity add a listener
void onAllCallsFinished(int availableUsers) {
//do what you want with availableUsers information
}
Call onAllCallsFinished(availableUsers) when callsFinished == contactsString.length.
There you can do what you want with that data. Update a view, call another service.
I had an issue where Text to Speech would not speak anything. I realised this was due to the fact that I was attempting to call 'Speak()' before TTS had initialised.
I need to wait until TTS has initialised, so that I can call 'Speak()' successfully. I thought doing something along the lines of this would work:
#Override
public void onInit(int status) {
if (status == TextToSpeech.SUCCESS) {
mTTSInitialised = true;
} else {
Log.e("TTS", "Initialisation Failed!");
}
}
...
while(!mTTSInitialised){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
But this fails to initialise at all. Is there a way to do this effectively?
The initialisation of the Text to Speech engine is asynchronous, which is why you realised you have to 'wait' for it to complete, before requesting that it processes an utterance.
Even when it eventually initialises successfully, it can be subsequently killed by the system, or it can of course fail to initialise, so you always need to be ready to handle a request to speak, where the engine isn't prepared.
Add the following helper class
public class PendingTTS {
private String pendingUtterance;
private int pendingQueueType;
public String getPendingUtterance() {
return this.pendingUtterance;
}
public void setPendingUtterance(#NonNull final String pendingUtterance) {
this.pendingUtterance = pendingUtterance;
}
public int getPendingQueueType() {
return this.pendingQueueType;
}
public void setPendingQueueType(final int pendingQueueType) {
this.pendingQueueType = pendingQueueType;
}
}
Assuming you're using an Activity, you need to declare the following variables:
private volatile PendingTTS pendingTTS;
private static final int MAX_INIT_ATTEMPTS = 4;
private volatile int initCount;
and initialise the Text to Speech object in onCreate()
tts = new TextToSpeech(YOURActivity.this, YOURonInitListener);
In your onInitListener you would check if there is any pending speech:
#Override
public void onInit(final int status) {
switch (status) {
case TextToSpeech.SUCCESS:
initCount = 0;
// Set up tts stuff
tts.setOnUtteranceProgressListener(YOURprogressListener);
if (pendingTTS != null) {
// We have pending speech, process it and check the result
int speechResult = tts.speak(pendingTTS.getPendingUtterance(),pendingTTS.getPendingQueueType(),
// remaining tts variables here)
switch (speechResult){
case TextToSpeech.SUCCESS:
// Result was successful
pendingTTS = null;
break;
case TextToSpeech.ERROR:
// Speech failed
// Check if it has repeatedly failed up to the max attempts
if(initCount < MAX_INIT_ATTEMPTS){
initCount ++;
tts = new TextToSpeech(YOURActivity.this, YOURonInitListener);
} else {
// Totally broken - let the user know it's not working
}
break;
}
} else {
// there was nothing to process
}
break;
case TextToSpeech.ERROR:
// Check if it has repeatedly failed up to the max attempts
if(initCount < MAX_INIT_ATTEMPTS){
initCount ++;
tts = new TextToSpeech(YOURActivity.this, YOURonInitListener);
} else {
// Totally broken - let the user know it's not working
}
break;
}
I've glued the above together from my code - where the speech and initialisation methods are all separated, but I tried to give you an overview above of everything you need to handle.
Elsewhere in your code, when you make a tts.speak(//stuff here) request, you need to check the result as demonstrated above, to make sure it was successful. Again, in my code, this is separated into one single method. If it does fail, you need to set the PendingTTS parameters prior to attempting to initialise again:
pendingTTS = new PendingTTS();
pendingTTS.setPendingQueueType(// your queue type);
pendingTTS.setPendingUtterance(// your utterance);
It is is successful, make sure pendingTTS is set to null.
The overall design is that if the initialisation failed, it will attempt to initialise again, up to the maximum allowed attempts. If the speech fails, it will attempt to initialise the engine again, firstly setting the PendingTTS parameters.
Hope you managed to follow that.
Hmm..
Not a very good idea.
You can try to add the text to the TTS queue and let it do it's work. This snippet can be inside button click, etc as:
tts.speak(toSpeak, TextToSpeech.QUEUE_ADD, null);
Small tutorial that would help.
i have following function run on start and work perfectly.
i would like to add if condition in other function in order to check if device is still connected.
here is code
private final Handler mHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case BluetoothService.MESSAGE_STATE_CHANGE:
switch (msg.arg1) {
case BluetoothService.STATE_CONNECTED:
Toast.makeText(getApplicationContext(), "Connect successful",
Toast.LENGTH_SHORT).show();
btnClose.setEnabled(true);
btnSend.setEnabled(true);
btnSendDraw.setEnabled(true);
break;
case BluetoothService.STATE_CONNECTING:
Log.d("À¶ÑÀµ÷ÊÔ","ÕýÔÚÁ¬½Ó.....");
break;
case BluetoothService.STATE_LISTEN:
case BluetoothService.STATE_NONE:
Log.d("À¶ÑÀµ÷ÊÔ","µÈ´ýÁ¬½Ó.....");
break;
}
break;
case BluetoothService.MESSAGE_CONNECTION_LOST:
Toast.makeText(getApplicationContext(), "Device connection was lost",
Toast.LENGTH_SHORT).show();
btnClose.setEnabled(false);
btnSend.setEnabled(false);
btnSendDraw.setEnabled(false);
break;
case BluetoothService.MESSAGE_UNABLE_CONNECT:
Toast.makeText(getApplicationContext(), "Unable to connect device",
Toast.LENGTH_SHORT).show();
break;
}
}
};
other function is start like this
#Override
protected void onPostExecute(String result){
please help me!!
Thanks
ACL_CONNECTED/DISCONNECTED is not exactly reliable, I have learned by experience, because this might happen several times during a device's connection (example, if pin is required, you will get "connected", and then "disconnected" if timeout/wrong pin supplied. This does not necessarily indicate connection proper). This indicates the lower layer connection.
If you want to use a broadcast receiver, it would be better to use the broadcast that is specific to the profile that you have used (example A2DP). Each has it's own broadcast. Another thing you can listen to is Connectivity_state_changed from ConnectivityManager, for the type BLUETOOTH (haven't really tried this one).
Also, the way to check if it is connected, without a broadcast receiver, say, when you want to check in the background before updating an activity, would be to obtain the profile object, via something like:
mBluetoothAdapter.getProfileProxy(mContext, mA2DPProfileListener, BluetoothProfile.A2DP);
where mA2DPProfileListener is a ServiceListener object:
<code>
private ServiceListener mA2DPProfileListener = new ServiceListener(){
//anonymous inner type. etc.
public void onServiceConnected(int profile, BluetoothProfile proxy) {
//cast the BluetoothProfile object to the profile you need, say
//BluetoothA2DP proxyA2DP = (BluetoothA2DP) proxy;
int currentState = proxyA2DP.getConnectionState(mDevice);
//mDevice is the BluetoothDevice object you can get from
//BluetoothAdapter.getRemote...
}
public void onServiceDisconnected(int profile) {
}
}
</code>
you can check what currentState points to, and determine if the device is connected/disconnected/connecting, etc.
HTH,
Sreedevi.
I've already bound an activity to my service following this tutorial.
http://developer.android.com/guide/components/bound-services.html
I'm able to call service functions, but what if I want to for example, change some of my textviews or disable some of the toggle buttons because of work done on the service (and from the service). Would there be an easy to way to do this?
You can use messages to send information between activities and services. This is an easy way to send simple data, but may not be the best option if you need to send data very frequently, or send complicated data. This is an example of some code I have in one of my apps with a service and an activity which communicate:
Code in the activity:
//this is where you set what you want to happen
class IncomingHandler extends Handler {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
//this switch reads the information in the message (usually just
//an integer) and will do something depending on which integer is sent
case 1: do_something();
case 2: do_something_2(); //etc.
default:
super.handleMessage(msg);
}
}
}
final Messenger myMessenger = new Messenger(new IncomingHandler());
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className,
IBinder service) {
myService = new Messenger(service);
myCallbackText = (TextView)findViewById(R.id.tv01); //This is a text view which will display status information as needed
myCallbackText.setText("Attached.");
try {
Message msg = Message.obtain(null,
1);
msg.replyTo = mMessenger; //here we send an instance of our messenger implementation as the replyTo address
mService.send(msg);
msg = Message.obtain(null,
3, this.hashCode(), 0);
mService.send(msg); //send a message with the value "3"
} catch (RemoteException e) {
//nothing you can do if the server isn't active
}
Toast.makeText(Service_testActivity.this, R.string.remote_service_connected,
Toast.LENGTH_SHORT).show();//confirmation that the connection happened successfully
}
public void onServiceDisconnected(ComponentName className) {
// This is called when the connection with the service has been
// unexpectedly disconnected -- that is, its process crashed.
mService = null;
mCallbackText = (TextView)findViewById(R.id.tv01);//same textview as before
mCallbackText.setText("Disconnected.");
Toast.makeText(Service_testActivity.this, R.string.remote_service_disconnected,
Toast.LENGTH_SHORT).show();
}
};
Code in the service:
In the service, you will want to have code (very similar to the code in the activity) to receive a message and save the msg.replyTo field as a Messenger object. There is an example somewhere which will have you make an object and then use an IncomingHandler like this:
ArrayList<Messenger> mClients = new ArrayList<Messenger>();
class IncomingHandler extends Handler {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_REGISTER_CLIENT:
mClients.add(msg.replyTo);
break;
case MSG_UNREGISTER_CLIENT:
mClients.remove(msg.replyTo);
break;
default:
super.handleMessage(msg);
}
}
}
This can allow your service to keep track of multiple clients at once and send messages to specified clients. To send a message simply use something like this:
mClients.get(1).send(Message.obtain(null, 3, new Random().nextInt(), 0));
//sends a message to the first client saved in the list