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Thread with (textView and progressbar)

I am programming an app in Android, where I obtain the data from the microphone, it works fine, I am able to save the amplitude of the sound. And I can update the progresssbar.
barraThread = new Thread(new Runnable() {
public void run(){
while (isRecording){
actualizarBarra(getAmplitud());
//lector.setText(String.valueOf(getAmplitud()));
}
}
},"barra Thread");
-Where: actualizarBarra(getAmplitud()); update the value of the progressbar with the actual amplitude.
My problems is that if I try to update a textView from that point, I get the error (
“Only the original thread that created a view hierarchy can touch its
views.”
So I tried to update the textView using a "Handler" and also using "runOnUiThread(new Runnable() {..." but the app runs very slow and sometime crash. Do you know any way to update the progressbar and the textview at the same time, in a properly way?,
Thanks a lot
Using the the runOnUiThread solution.
private void actualizarInterfaz() {
runOnUiThread(new Runnable() {
#Override
public void run() {
actualizarBarra(getAmplitud());
lector.setText(String.valueOf(getAmplitud()));
}
});
}
and then in a loop:
while(isRecording){
actualizarInterfaz();
}
Was no error, just the app get frozen, so I can not see any log at the LogCat, just like is running normally but in fact does not.
Thanks

You should update TextView on the UI (main) thread only. The handler approach is ok (there are others). As for the performance issue, I suspect the recording make too many frequent updates. Try to introduce delay in updating the view and not update it every time

Android TextView not fully updating

I have a thread which updates a textview using a runnable:
// runnable to allow updating the UI from the thread
Runnable updateTextView = new Runnable() {
public void run() {
mTextView.setText(mDisplayedText);
mTextView.invalidate();
}
};
However, the text does not update properly. It works for the first few writes, then only writes half the text, leaving the second half of the previous text there.
Turning the screen around causes it to refresh and draws it correctly.
The textview is multiline and I write a string to it which contains \n characters for the end of lines.
The invalidate call above makes no difference.
Any ideas?
UPDATE: mDisplayedText is declared in the activity which also contains my thread class. in the thread run loop, I call:
mDisplayedText = getText()
runOnUiThread(updateTextView);
The loop contains a 100ms sleep, but it only writes to the text when it has changed so in reality it will be less than once a second
ANSWER:
Slightly embarrassing this. The problem was in other code.
I was receiving a UDP socket into the same packet, and reading the packet.getData into a new string.
This was copying the whole packet into the string, rather than just the bytes received in that message.
The second problem was that I needed to call packet.setLength each time to set the length available to the whole packet.
Thanks for the answers!

you can only update your UI on UI thread, put your setText() method inside this
runOnUiThread(new Runnable() {
#Override
public void run() {
btn.setText(someValue);
}
});

Runnable is an interface. Think of it like a set of commands ready for execution. You can use a Handler to work with your code:
Handler textViewHandler = new Handler();
// runnable to allow updating the UI from the thread
Runnable updateTextView = new Runnable() {
public void run() {
mTextView.setText(mDisplayedText);
}
};
textViewHandler.post(updateTextView);
Also, please consider #Karakuri's suggestion.

Android Thread modify EditText

I am having a problem with modifying EditText in another function started by the thread:
Thread thRead = new Thread( new Runnable(){
public void run(){
EditText _txtArea = (EditText) findViewById(R.id.txtArea);
startReading(_txtArea);
}
});
my function is as follows:
public void startReading(EditText _txtArea){
_txtArea.setText("Changed");
}
It always force closes while trying to modify the edittext. Does someone know why?

UI views should not be modified from non-UI thread. The only thread that can touch UI views is the "main" or "UI" thread, the one that calls onCreate(), onStop() and other similar component lifecycle function.
So, whenever your application tries to modify UI Views from non-UI thread, Android throws an early exception to warn you that this is not allowed. That's because UI is not thread-safe, and such an early warning is actually a great feature.
UPDATE:
You can use Activity.runOnUiThread() to update UI. Or use AsyncTask. But since in your case you need to continuously read data from Bluetooth, AsyncTask should not be used.
Here is an example for runOnUiThread():
runOnUiThread(new Runnable() {
#Override
public void run() {
//this will run on UI thread, so its safe to modify UI views.
_txtArea.setText("Changed");
}
});

First of all take a look at your log, it usually contains a stack trace when an app shuts down.
You shouldn't run the thread like you normally do, instead use runOnUiThread:
Runnable thRead = new Runnable(){
public void run() {
EditText _txtArea = (EditText) findViewById(R.id.txtArea);
startReading(_txtArea);
}
};
runOnUiThread(thRead);
The explaination: Only the UI thread is allowed to change the state of UI components.

This article may help you.
http://android-developers.blogspot.com/2009/05/painless-threading.html
There are few options:
1. run it on UI thread Activity.runOnUiThread(Runnable)
2. use AsyncTask

Except runOnUiThread() (which works), there is also another way, which I know of:
Define a handler in your UI (Activity) class:
public class MainActivity extends Activity {
.....
Handler uiThreadHandler = new Handler() {
public void handleMessage(Message msg) {
Object o = msg.obj;
if (o==null) o = "";
TextView textIn = (TextView)findViewById(R.id.textin);
textIn.setText(o.toString());
}
};
}
and from inside some thread you can call it:
Message msg = uiThreadHandler.obtainMessage();
msg.obj = "Text for EditView";
uiThreadHandler.sendMessage(msg);

By default, the main thread is the UI thread. All code that modifies the appearance of the application needs to be run in this thread. If you want to have multiple threads in your application that can modify the UI I would suggest using the AsyncTask class.
public someMethod(){
new ChangeTextTask().execute();
}
private class ChangeTextTask extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
startReading(_txtArea);
return null;
}
}
However, you need to take steps to prevent multiple threads from accessing the EditText object at once. Otherwise you'll wind up getting a CurrentModificationException error.
http://developer.android.com/reference/android/os/AsyncTask.html

Android: Activity taking too long to display because of web service Http Request

One of my activities make a http request to a webservice to get some weather data when I start the application.
The issue that the activity will take 3-4 seconds to display because of the webservice request. ( Tested on actual device )
I know I m not doing this the right way. All I m doing is on the onCreate method, I m making the request , getting the xml back, parsing and displaying the data.
What is the best way to deal with webservice requests in Android so the application won't display a white screen while the request is being made? Maybe some threads.......
I know this is not happening on other application I have in my device that make request to get live data.
Notes:
1) The xml I getting back is not that big ( 5 elements with 5 nested elements on each one).
2) I tried with the 3G network and Wifi but the response time is still the same.
sample code:
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.clock_weather);
// this is where it is making the request and parsing the xml.
WeatherSet set = getWeatherCondition("New York, NY");
TextView currentWeather = (TextView) findViewById(R.id.current_weather);
currentWeather.setText("" + set.getWeatherCurrentCondition().getTempFahrenheit());
TextView currentWeatherH = (TextView) findViewById(R.id.current_weatherH);
currentWeatherH.setText("H: " + set.getWeatherForecastConditions().get(0).getTempMaxFahrenheit());
TextView currentWeatherL = (TextView) findViewById(R.id.current_weatherL);
currentWeatherL.setText("L: " + set.getWeatherForecastConditions().get(0).getTempMinFahrenheit());
ImageView currentWeatherIcon = (ImageView) findViewById(R.id.current_weather_icon);
String imageUrl = set.getWeatherCurrentCondition().getIconURL();
Drawable bitmapDrawable = getImageBitmap(imageUrl);
currentWeatherIcon.setImageDrawable(bitmapDrawable);
setForecastInfo(set, R.id.day1, R.id.day1_icon, R.id.day1_temp, 1 );
setForecastInfo(set, R.id.day2, R.id.day2_icon, R.id.day2_temp, 2 );
setForecastInfo(set, R.id.day3, R.id.day3_icon, R.id.day3_temp, 3 );
setForecastInfo(set, R.id.day4, R.id.day4_icon, R.id.day4_temp, 4 );
}

The time for your response is unpredictable - your network connection can be very poor and take seconds to transfer a few bytes. So the correct way to do this ( as you propose ) is to use thread. In our case android provides very useful class to handle this situations - AsynTask. After you read the docs you will notice that it has 3 very powerful methods that can help you
onPreExecute runs in the ui thread - very helpful to show some spinner or some progress indicator to show the user that you are doing some work in background
doInBackground runs in background - do your background work here
onPostExecute runs in the ui thread- when your are done with your background work hide the progress and update the gui with the newly received data.

private class getWeather extends AsyncTask<Context, Void, Cursor> {
ProgressDialog dialog = null;
protected void onPreExecute () {
dialog = ProgressDialog.show(CLASS.this, "",
"Loading. Please wait...", true);
}
#Override
protected Cursor doInBackground(Context... params) {
WeatherSet set = getWeatherCondition("New York, NY");
return null;
}
protected void onPostExecute(Cursor c) {
dialog.dismiss();
}
}
Then where you have WeatherSet set = getWeatherCondition("New York, NY"); now, you'll put new getWeather().execute(this);
I suggest reading how the AsyncTask works, and see why this should work. It goes outside the onCreate() method.

This is regarding AsyncTask, I just want to help understanding the concept, it is really useful:
DownloadFilesTask dft = new DownloadFilesTask(this);
//Executes the task with the specified parameters
dft.execute(Void1...);
...
...
...
dft.cancel(boolean);
private class DownloadFilesTask extends AsyncTask<Void1, Void2, Void3> {
//Runs on the UI thread before doInBackground(Void1...)
protected void onPreExecute() {
}
//runs in BACKGROUNG threat
protected Void3 doInBackground(Void1... urls) {
//it can be invoked from doInBackground(Void1...) to publish updates
//on the UI thread while doInBackground(Void1...) is still running
publishProgress(Void2...);
}
//Runs on the UI thread after publishProgress(Void2...) is invoked
protected void onProgressUpdate(Void2... progress) {
}
//Runs on the UI thread after doInBackground(Void1...) has finished
protected void onPostExecute(Void3) {
}
//runs in UI threat after cancel(boolean) is invoked and
//doInBackground(Void1...) has finished
protected void onCancelled(Void3) {
}
}

You can use AsynchTask class for your web service.You can write your time consuming task in on doInBackground.Also you can use a progress Dialog.
Here You can see how to work with AsynchTask.You can also update your UI while web service is parsing without waiting for the complete parsing using onPostUpdate method.

The response time is normal. Don't worry. Make it a point to run the web-service call in a separate thread.
Regarding the white screen, as soon as you start the web service call, fire a ProgressDialog box. This will run till you receive the response. As soon as you receive the response, dismiss the progressDialog box and start the new activity where you can display the result.
Use the following URLs for reference
http://www.helloandroid.com/tutorials/using-threads-and-progressdialog
http://thedevelopersinfo.wordpress.com/2009/10/16/showing-progressdialog-in-android-activity/
I have implemented the idea I'm giving you and it works perfectly.
Hope I was of some help

What is the best way to deal with webservice requests in Android so the application won't display a white screen while the request is being made?
Because you said 'white screen" I am assuming you are not using a progress dialog. You need to show a progress spinner/dialog to let the user know you are processing.
Have you check how large the data is? If the data is too large you really cant do anything , if you have control over the service its best to reduce the size.

Set TextView value inside a thread in android

I am getting a crash under the fllowing circumstances. I am running a thread in the following way:
Thread t = new Thread(){
public void run() {
text.setText("hello");
}
};
t.start;
The crash occurs if I try to set the value of a TextView in my xml, (the reference to text is already available).
Am I doing something fundamentally wrong? Kindly point out where am going wrong.

You can only access user interface components from the UI thread.
Android has a few things to make this easy, such as the method runOnUiThread and the class AsyncTask.
For more reading see Painless Threading and Processes and Threads in the Android documentation.

You should access android ui toolkit widgets only on the UI thread. Read http://developer.android.com/resources/articles/painless-threading.html.

use Handler class and check it for more relevant methods
Handler mHandler;
mHandler=new Handler(){
hdandleMessage(Message what){
text.setText("hello");
}
};
Thread t = new Thread(){
public void run()
{
mHandler.sendEmptyMessage(int what)
}
};
t.start;