I want to wirte an android app that will read input from user each time i press abutton and will handle it in different thread(not activity) also i dont want to open new thread each time i need an example for that.
Thanks a lot!
Get the text from user input field:
EditText editText = findViewById(R.id.yourEditTextId);
final String text = editText.getText().toString;
Then you could do something like this:
Handler handler = new Handler();
final Runnable r = new Runnable() {
public void run() {
// do something with String text
}
};
handler.post(r);
Or this:
new Thread(new Runnable() {
public void run() {
// do something with String text
}
}).start();
You can find info about threads in Android here: http://developer.android.com/guide/components/processes-and-threads.html
you could use this link here
`Thread thread = new Thread()
{
#Override
public void run() {
try {
// do something here
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
thread.start();`
Related
How I can set dynamically set the progressbar status after reading a value from db SQLite?
I have this code.
int i = 0;
while (!c.isAfterLast()) {
i++;
pb.setProgress(i)
}
But my problem is that progress bar is update only at finish while so without "liveEffect"
You can use runOnUiThread method of Activity class:
runOnUiThread(new Runnable() {
#Override
public void run() {
pb.setProgress(i);
}
});
More here: https://developer.android.com/reference/android/app/Activity.html#runOnUiThread(java.lang.Runnable)
Actually, execution time is too low that by live effect not appear . take large cursor around 10000 value then apply loop now you can see progress
I resolved my problem with Handler and Thread.sleep (for simulate live)
new Thread(new Runnable() {
public void run() {
do {
mProgressStatus++;
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
mHandler.post(new Runnable() {
public void run() {
pb.setProgress(mProgressStatus);
}
);
} while (c.moveToNext());
}
}).start();
Can I update two textviews inside a runnable?
Because my code can only update one textview.
I got this method that updates 2 textviews that contains the address and date from the EXIF data of a photo.
public void launchRingDialog() {
final ProgressDialog ringProgressDialog = ProgressDialog.show(ReportIncident.this, "Please wait ...", "Rendering Image EXIF Data ...", true);
ringProgressDialog.setCancelable(false);
new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(5000);
loadExifData();
r.setDate(mExif.getAttribute(ExifInterface.TAG_DATETIME));
tvLocation.setText(getaddress());
tvTime.setText(r.getStringDate());
r.setLati(Double.parseDouble(mExif.getAttribute(ExifInterface.TAG_GPS_LATITUDE)));
r.setLongi(Double.parseDouble(mExif.getAttribute(ExifInterface.TAG_GPS_LONGITUDE)));
} catch (Exception e) {
}
ringProgressDialog.dismiss();
}
}).start();
}
You cannot update the UI in a different Thread than the UI Thread in Android. To do that, a simple way you can use is:
Handler handler = new Handler(Looper.getMainLooper());
handler.post(new Runnable(){
tvLocation.setText(getaddress());
tvTime.setText(r.getStringDate());
});
I am very confused as to why I cannot get this to work. I want to have a screen with no buttons run for 5 seconds while I do some things in the background, then navigate back to another screen. Is this not possible?
I have tried to put the code to run the background items in onCreate, onStart, and onResume, and all of these methods are fired before the screen actually displays. Is there another way to do this?
Edit The most recent version of my code:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sync);
}
protected void onResume(){
super.onResume();
commitSync();
}
private void commitSync(){
TextView monthDayYear = (TextView)findViewById(R.id.month_day_year);
TextView hourMinuteSecond = (TextView)findViewById(R.id.hour_minute_second);
_application = (App)getApplicationContext();
try {
CountDownLatch latch = new CountDownLatch(1);
latch.await(5, TimeUnit.SECONDS);
//Ensure that we have flash
if(getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH)) {
Camera androidCamera = Camera.open();
Camera.Parameters p = androidCamera.getParameters();
p.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
androidCamera.setParameters(p);
//Flash and then turn off
androidCamera.startPreview();
latch.await(50, TimeUnit.MILLISECONDS);
androidCamera.stopPreview();
//Flash screen white
//Get date and time
Module syncModule = _application.getModule();
syncModule.start();
Calendar syncTime = syncModule.getDateAndTime();
//http://stackoverflow.com/questions/21988004/get-time-in-hhmmss-from-seconds-in-java
monthDayYear.setText(new SimpleDateFormat("MM/dd/yyyy").format(syncTime.getTime()));
hourMinuteSecond.setText(new SimpleDateFormat("HH:mm:ss:00").format(syncTime.getTime()));
//Navigate back to MainActivity
Intent mainActivityIntent = new Intent(SyncActivity.this, MainActivity.class);
startActivityForResult(mainActivityIntent, 1);
} else {
throw new Exception("Cannot access Android Flash");
}
} catch (Exception ex) {
Util.appendLog("Exception occured in Sync: " + ex.getMessage());
}
}
Maybe this help you:
Handler handler = new Handler();
handler.postDelayed(new Runnable()
{
#Override
public void run() {
// Do some work like:
finish();
}
}, 500);
This run a code after some delay and you can put this code in your desired screen.
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
#Override
public void run() {
//The code you want to execute
}
}, timeUntilExecution);
This code should execute that run() method after the timeUntilExecution variable (in milliseconds) you could use this to execute what you want to do after the delay. Hope this helps.
I want to write a download manager app, in the activity I add a progress bar which show the current progress to the user, now if user touch the back button and re-open the activity again this ProgressBar won't be updated.
To avoid from this problem I create a single thread with unique name for each download that keep progress runnable and check if that thread is running in onResume function, if it is then clone it to the current thread and re-run the new thread again but it won't update my UI either, Any ideas !?
#Override
public void onResume()
{
super.onResume();
Set<Thread> threadSet = Thread.getAllStackTraces().keySet();
Thread[] threadArray = threadSet.toArray(new Thread[threadSet.size()]);
for (int i = 0; i < threadArray.length; i++)
if (threadArray[i].getName().equals(APPLICATION_ID))
{
mBackground = new Thread(threadArray[i]);
mBackground.start();
downloadProgressBar.setVisibility(View.VISIBLE);
Toast.makeText(showcaseActivity.this
, "Find that thread - okay", Toast.LENGTH_LONG).show();
}
}
private void updateProgressBar()
{
Runnable runnable = new updateProgress();
mBackground = new Thread(runnable);
mBackground.setName(APPLICATION_ID);
mBackground.start();
}
private class updateProgress implements Runnable
{
public void run()
{
while (Thread.currentThread() == mBackground)
try
{
Thread.sleep(1000);
Message setMessage = new Message();
setMessage.what = mDownloadReceiver.getProgressPercentage();
mHandler.sendMessage(setMessage);
}
catch (InterruptedException e)
{
Thread.currentThread().interrupt();
}
catch (Exception e)
{/* Do Nothing */}
}
}
private Handler mHandler = new Handler()
{
#Override
public void handleMessage(Message getMessage)
{
downloadProgressBar.setIndeterminate(false);
downloadProgressBar.setProgress(getMessage.what);
if (getMessage.what == 100)
downloadProgressBar.setVisibility(View.GONE);
}
};
Download button code:
downloadBtn.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View arg0)
{
downloadProgressBar.setVisibility(View.VISIBLE);
downloadProgressBar.setIndeterminate(true);
downloadProgressBar.setMax(100);
Intent intent = new Intent(showcaseActivity.this, downloadManagers.class);
intent.putExtra("url", "http://test.com/t.zip");
intent.putExtra("receiver", mDownloadReceiver);
startService(intent);
updateProgressBar();
}
});
I'd strongly recommend reading the Android Developer blog post on Painless Threading. As it states, the easiest way to update your UI from another thread is using Activity.runOnUiThread.
I'm trying to write code to pull a server every second for updated messages. The messages then get displayed in a text view. If I do not change the text in the text view it runs fine. It will crash if I try to change the textview on the thread. IF i change it not on the thread works fine.
I'm assuming the thread cannot access the main threads memory? How can I set the text in the view with the text just loaded over the internet?
In the code below I have a thread that does a endless loop with a sleep. It calls a method called SendMessage. Send Message loads in text over the internet and at the end tries to update the View with it. It causes a exception when this happens.
code:
public class cChat extends cBase implements OnClickListener {
/** Called when the activity is first created. */
TextView mUsers;
TextView mComments;
int i=0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.chat);
mUsers=( TextView) findViewById(R.id.viewusers);;
mComments=( TextView) findViewById(R.id.viewchats);;
Thread thread = new Thread()
{
#Override
public void run() {
try {
int t=0;
while(true)
{
SendMessage();
sleep(1000*5);
t++;
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
thread.start();
}
public void onClick(View v) {
} // end function
// send a uypdate message to chat server
// return reply in string
void SendMessage()
{
try {
URL url = new URL("http://50.63.66.138:1044/update");
System.out.println("make connection");
URLConnection conn = url.openConnection();
// set timeouts to 5 seconds
conn.setConnectTimeout(1000*5);
conn.setReadTimeout(5*1000);
conn.setDoOutput(true);
BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
// String line;
String strUsers=new String("");
String strComments=new String("");
String line=new String();
int state=0;
while ((line= rd.readLine() ) != null) {
switch(state){
case 0:
if ( line.contains("START USER"))
state=1;
if ( line.contains("START COMMENTS"))
state=2;
break;
case 1:
if ( line.contains("END USER"))
state=0;
else
{
strUsers+=line;
strUsers+="\n";
}
break;
case 2:
if ( line.contains("END COMMENTS"))
state=0;
else {
strComments+=line;
strComments+="\n";
}
break;
} // end switch
} // end loop
// the next line will cause a exception
mUsers.setText(strUsers);
mComments.setText(strComments);
} catch (Exception e) {
i++; // use this to see if it goes here in debugger
// System.out.println("exception");
// System.out.println(e.getMessage());
}
} // end methed
}
use runOnUiThread as
YOUR_CURRENT_ACTIVITY.this.runOnUiThread(new Runnable() {
#Override
public void run() {
// the next line will cause a exception
mUsers.setText(strUsers);
mComments.setText(strComments);
//....YOUR UI ELEMENTS
}
});
EDIT :
see doc runOnUiThread
You can use a handler to post tasks (Runnables) to the UI/Main Thread:
private Handler handler = new Handler();
//...
Thread thread = new Thread()
{
#Override
public void run() {
try {
int t=0;
while(true)
{
handler.post(new Runnable() {
#Override
public void run() {
SendMessage();
}
});
sleep(1000*5);
t++;
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
You can't touch an UI widget from a thread different than the one used to create it (the UI thread). But if you have a reference to the Activity, you can simply do:
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
mUsers.setText(strUsers);
mComments.setText(strComments);
}
});
which would require strUsers to be accessible by the anonymous class. For that you can simply do:
final String finalUseres = strUsers;
and use finalUsers within run().
Try using a Service to continuously pull/send data to server. This will reduce the load on your UI-Thread.
the Andoid UI toolkit is not thread-safe. So, you
must not manipulate your UI from a worker thread
To fix this problem, Android offers several ways to access the UI thread from other threads. Here is a list of methods that can help:
Activity.runOnUiThread(Runnable)
View.post(Runnable)
View.postDelayed(Runnable, long)
you can also use AsyncTask.
see this tutorial on process and threads in android.