This is my scenario. A class A implements Runnable. When user click a button, there will show a progress dialog and call the method searchMap() to search an address. The dialog dismisses after 10 seconds. I really misunderstand how to execute the run() method. this is my creepy code.
public class AddLocationMapActivity extends MapActivity implements Runnable {
private ProgressDialog progressDialog;
private MyHandler myHandler;
private Message msg;
#Override
public void run() {
mapCurrentAddress();
}
public void mapLocation(View v) // click event here{
progress();
Thread thread = new Thread(this);
thread.start();
}
private class MyHandler extends Handler{
#Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch(msg.what) {
case NOT_OK_MESSAGE: // Fail
alert(AddLocationMapActivity.this, message());
progressDialog.dismiss();
break;
case OK_MESSAGE: // Success
found(); // Point to the appropiate address
progressDialog.dismiss();
break;
case EXPTION_MESSAGE: // Exception
alert(AddLocationMapActivity.this, "Unexpected error");
progressDialog.dismiss();
break;
}
}
}
protected void mapCurrentAddress() {
String addressString = addressText.getText().toString();
Geocoder g = new Geocoder(this);
List<Address> addresses;
myHandler = new MyHandler();
msg = myHandler.obtainMessage();
try {
addresses = g.getFromLocationName(addressString, 1);
if (addresses.size() > 0) {
//address = addresses.get(0);
msg.what = OK_MESSAGE;
myHandler.sendEmptyMessage(OK_MESSAGE);
} else {
// show the user a note that we failed to get an address
myHandler.sendEmptyMessage(NOT_OK_MESSAGE);
}
} catch (IOException e) {
// show the user a note that we failed to get an address
//e.printStackTrace();
myHandler.sendEmptyMessage(EXPTION_MESSAGE);
}
}
private void progress() {
progressDialog = ProgressDialog.show(this,
"Checking", "Contacting Map Server");
Thread progressThread = new Thread();
progressThread.start();
}
}
When click event occurs, the program fails with exception Uncaught Handler
here's a little bit of my threading code that doesn't give away too much...
progress = ProgressDialog.show(this, "", "Loading...", true);
new Thread(new Runnable() {
#Override
public void run()
{
// get some network content
Chooser.this.runOnUiThread(new Runnable() {
#Override
public void run()
{
progress.dismiss();
// update the UI
}
});
}
}).start();
Related
thread = new Thread(new Runnable() {
#Override
public void run() {
synchronized (datahandler) {
while (true) {
try {
if (datahandler.getCount() > 0) {
commitData();
}
datahandler.wait();
} catch (InterruptedException e) {
e.printStackTrace();
Log.e("Service", e.toString());
}
}
}
}
});
thread.start();
Commitdata to connect and commit data form datahandler to server. But I dont kow why it shows not respone dialog. If I do not close it, it continouns to commit. Why UI is influenced when I commit data in other thread
public class ThreadsLifecycleActivity extends Activity {
// Static so that the thread access the latest attribute
private static ProgressDialog dialog;
private static Bitmap downloadBitmap;
private static Handler handler;
private ImageView imageView;
private Thread downloadThread;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// create a handler to update the UI
handler = new Handler() {
#Override
public void handleMessage(Message msg) {
imageView.setImageBitmap(downloadBitmap);
dialog.dismiss();
}
};
// get the latest imageView after restart of the application
imageView = (ImageView) findViewById(R.id.imageView1);
Context context = imageView.getContext();
System.out.println(context);
// Did we already download the image?
if (downloadBitmap != null) {
imageView.setImageBitmap(downloadBitmap);
}
// check if the thread is already running
downloadThread = (Thread) getLastNonConfigurationInstance();
if (downloadThread != null && downloadThread.isAlive()) {
dialog = ProgressDialog.show(this, "Download", "downloading");
}
}
public void downloadPicture(View view) {
dialog = ProgressDialog.show(this, "Download", "downloading");
downloadThread = new MyThread();
downloadThread.start();
}
// save the thread
#Override
public Object onRetainNonConfigurationInstance() {
return downloadThread;
}
// dismiss dialog if activity is destroyed
#Override
protected void onDestroy() {
if (dialog != null && dialog.isShowing()) {
dialog.dismiss();
dialog = null;
}
super.onDestroy();
}
static public class MyThread extends Thread {
#Override
public void run() {
try {
// Simulate a slow network
try {
new Thread().sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
downloadBitmap = downloadBitmap("http://www.devoxx.com/download/attachments/4751369/DV11");
// Updates the user interface
handler.sendEmptyMessage(0);
} catch (IOException e) {
e.printStackTrace();
} finally {
}
}
}
}
//==========================
You can sea in code that handlers are used to post message on GUI thread. further you can read about it over here
http://www.vogella.com/tutorials/AndroidBackgroundProcessing/article.html
Also Read This http://android-developers.blogspot.de/2010/07/multithreading-for-performance.html
the Problem I am having is that the PostExecute is not firing.
I see the log tag for background but P.E. never fires.
I am invoking this task from a timer like this:
findViewById(R.id.buttonstart).setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
try {
openFile("FeedTimerTask.html");
Timer t = new Timer("FeedTimerTask", true);
timerTask = new FeedTimerTask();
t.schedule(timerTask, 2000, 20000);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Runnable runme = new Runnable() {
#Override
public void run() {
timestart = Calendar.getInstance().getTimeInMillis();
provider.refreshNoCache();
}
};
class FeedTimerTask extends TimerTask{
#Override
public void run() {
try{Looper.prepare();}catch(Exception e){};
runme.run();
}
}
Here is the main task itself from inside the dataprovider class invoked with "provider.refreshNoCache();" above:
// threaded rteftesh tasks
#SuppressWarnings("rawtypes")
public class RefreshTask extends SupportAsyncTask {
private int errorcodecode = 0;
private ProgressDialog dialog=null;
private Exception mainExeption=null;
protected String waitMessage = "Laddar ner information..";
private boolean useCache;
public RefreshTask(boolean useCache) {
this.useCache = useCache;
}
public void onPreExecute() {
data = null;
if (showSpinnerOnRefresh){
dialog = ProgressDialog.show(context, "", waitMessage , true);
dialog.show();
}
}
protected Object doInBackground(Object... params) {
errorcodecode = 1;
try {
invokeFeedRead();
Log.e("DataProvider", "Bkgtask...");
errorcodecode = 0;
} catch (BrJSONException e) {
Log.e("[ERROR]","PROVIDER "+e.getMessage());
mainExeption = e;
errorcodecode = 1;
} catch (IOException e) {
Log.e("[ERROR]","PROVIDER "+e.getMessage());
mainExeption = e;
errorcodecode = 2;
} catch (Exception e) {
Log.e("[ERROR]","PROVIDER "+e.getMessage());
mainExeption = e;
errorcodecode = 3;
}
if (errorcodecode==0){
}
return null;
}
#Override
protected void onCancelled() {
super.onCancelled();
Log.e("DataProvider", "Cancelled...");
if (dialog != null)
try{dialog.dismiss();}catch(Exception e){}
BrAlert.Show(context, "Obs", BrAppConfig.ServerError+" (timeout)", 0);
onError_IO(new IOException("Timeout!"));
errorcodecode=2;
}
#Override
protected void onPostExecute(Object result) {
// super.onPostExecute(result);
Log.e("DataProvider", "PostExec...");
if (dialog != null)
try{dialog.dismiss();}catch(Exception e){}
switch (errorcodecode) {
case 0:
onFeedLoaded();
cacheAge = System.currentTimeMillis();
break;
case 1:
onError_DataFormat(mainExeption);
break;
case 2:
onError_IO(mainExeption);
break;
default:
onError_GeneralExeption(mainExeption);
}
}
}
Your task is cancelled even before it reached onPostExecte method. If the task is cancelled before it reaches onPostExecute Method. It will not trigger onPostExecute but trigger onCancelled Method. Please provide enough time to finish the task.
I found out the problem in the end. It was to do with the scope.
I needed a handler to invoke the other thread.
Here is the solution for others may find helpful:
in on create:
tickHandler = new Handler();
tickTimer = new Timer();
tickTimer.schedule(new FeedTimerTask(),
0,
50000); //FPS
The handler class.
class FeedTimerTask extends TimerTask{
private Runnable runable;
public FeedTimerTask(){
super();
runable = new Runnable(){
#Override
public void run() {
timestart = Calendar.getInstance().getTimeInMillis();
provider.refreshNoCache();
}
};
}
#Override
public void run() {
tickHandler.post(runable);
}
}
Here is my code & probelm.
static Throwable t= null;
static String responseFromServer = "";
static Activity a ;
static Handler mHandler = new Handler();
public static String sendToServer(final Activity act, final String data)
{
progDailog = ProgressDialog.show(act, "", " Please wait...", true);
progDailog.setCancelable(true); //BUT this not displaying
Thread th = new Thread()
{
public void run(){
try{
// .........code ... SENDING data to server
responseFromServer = httpclient.execute(httppost, new BasicResponseHandler()).trim();
mHandler.post(showResponse);
}
catch (Exception e)
{
t = e;
e.printStackTrace();
progDailog.dismiss();
mHandler.post(exception);
}
}
};
th.start();
th.join();
return responseFromServer;
}
private static Runnable showResponse = new Runnable()
{
public void run(){
Toast.makeText( a, responseFromServer, Toast.LENGTH_SHORT).show();
progDailog.dismiss();
}
};
private static Runnable exception = new Runnable()
{
public void run(){
Toast.makeText( a, t + " ", Toast.LENGTH_SHORT).show();
progDailog.dismiss();
}
};
Why progressdialog is not getting displayed ?
And Where is the correct place to display it ?
progressDialog.show() can be executed only from the UI thread.
just do the following:
instead of:
progDailog = ProgressDialog.show(act, "", " Please wait...", true);
use this code:
a.runOnUiThread(new Runnable() {
#Override
public void run() {
progDailog = ProgressDialog.show(act, "", " Please wait...", true);
}
});
same thing with the dismiss() method
You should make use of AsyncTask other than using Threads. The UI can be handled only from the UI thread. You can not handle the UI thread from the other threads.
For more information on this please read my blog at below link
http://pavandroid.blogspot.in/2010/09/how-to-create-calendar-in-android.html
I have a service which contains a Timer and TimerTask for receiving data from Webservice in periods of time. everything works fine except Toast. I want to show a Toast to user in procSendMapMovements but i get exception. How can I use Toast in it?
class taskSendMapMovements extends TimerTask {
#Override
public void run() {
hhSendMapMovements.sendEmptyMessage(0);
}
};
// /////////////////////
final Runnable rSendMapMovements = new Runnable()
{
public void run()
{
procSendMapMovements();
}
};
final Handler hhSendMapMovements = new Handler(new Callback() {
#Override
public boolean handleMessage(Message msg) {
performOnBackgroundThread(rSendMapMovements);
return false;
}
});
// /////////////////////
public void procSendMapMovements() {
try {
Toast.makeText(SrvDataExchange.this,
"some texts"
Toast.LENGTH_SHORT).show();
// exception here
// my process
} catch (Exception e) {
}
}
#Override
public void onStart(Intent intent, int startId) {
try {
timerSendMapMovements = new Timer();
timerSendMapMovements
.schedule(new taskSendMapMovements(),
10*60*1000,
10*60*1000);
//
} catch (NumberFormatException e) {
Toast.makeText(this, "error running service: " + e.getMessage(),
Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(this, "error running service: " + e.getMessage(),
Toast.LENGTH_SHORT).show();
}
}
public static Thread performOnBackgroundThread(final Runnable runnable) {
final Thread t = new Thread() {
#Override
public void run() {
try {
runnable.run();
} finally {
}
}
};
t.start();
return t;
}
Create a handler to display toast.
Use following:
where you want to display toast call:
//printToast.sendEmptyMessage();//If you dont want to send no paramter
//if you want to send some object to handler
/*
Message msg=printToast.obtainMessage();
msg.obj=objToSent;
printToast.sendMessage(msg);
*/
final Handler printToast= new Handler(new Callback() {
#Override
public boolean handleMessage(Message msg) {
Toast.makeText....;
}
});
**
Handler printToast= new Handler(new Callback() {
#Override
public boolean handleMessage(Message msg) {
Toast.makeText....;
}
});
your Runnable
{
run()
{
do what ever you want
printToast.sendMessage(printToast.obtainMessage());
}
}
**
Implementing a Thread by providing a new class that extends Thread and overriding its run() method is new to me. I've tried all day to get it to work. Here's my code:
/*
* see http://developer.android.com/reference/java/lang/Thread.html
*/
class threadClass extends Thread {
private Handler mHandler;
private Message mMsg;
// constructor
public threadClass(Handler handler, Message msg) {
// do something like save the Handler reference
mHandler = handler;
mMsg = msg;
}
#Override
public void run() {
// do some background processing, call the Handler?
mHandler.sendMessage(mMsg);
}
}
public Thread passHandlerToThread(Handler handler) {
handler.sendEmptyMessage(10);
Message msg = Message.obtain();
msg.what = 10;
Thread thread = new threadClass(handler, msg);
return thread;
}
private Handler localHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
int what = msg.what;
if (what == 10) Log.i("localHandler", "what: " + what);
}
};
public void startThread() {
Thread thread = passHandlerToThread(localHandler);
thread.start();
}
I call startThread() in my LocalService onCreate() but nothing happens. What am I doing wrong? I was expecting localHandler() to be called twice: once in passHandlerToThread() and again in run().
Do something like this:
private final Handler handler = new Handler();
// toast runnables
final Runnable updateTwitterNotification = new Runnable() {
#Override
public void run() {
dismissProgressSpinner();
Toast.makeText(getBaseContext(), "Tweet sent!", Toast.LENGTH_LONG).show();
}
};
final Runnable updateCreateError = new Runnable() {
#Override
public void run() {
Toast.makeText(getBaseContext(), "Tweet error!", Toast.LENGTH_LONG).show();
}
};
postMessageInThread();
//implementation:
private void postMessageInThread() {
Thread t = new Thread() {
#Override
public void run() {
try {
connectToTwitterService() // or whatever
handler.post(updateTwitterNotification);
} catch (Exception ex) {
Log.e(TAG, "Error sending msg", ex);
handler.post(updateCreateError);
}
}
};
t.start();
}