Develop Reference

how to start first thread complete to after second thread start

Am using some method i need to some method complete to start to another method so that am using thread function, How to start one thread follow by to second thread start?
Thread thread1 = new Thread(new Runnable() {
#Override
public void run() {
try {
loadIrrigationSourceMaster();
loadIrrigationMaster();
loadSeasonMaster();
loadFactoryMaseter();
} catch (Exception e) {
e.printStackTrace();
}
}
});
thread1.start();
Thread thread2 = new Thread(new Runnable() {
#Override
public void run() {
try {
loadTransport();
plantTypeMaster();
plotOwnerTypeMaster();
ExitRatoonMaster();
} catch (Exception e) {
e.printStackTrace();
}
}
});
thread2.start();

(new Thread(new Runnable() {
#Override
public void run() {
//TODO: fist thread code here
Log.w("tag","1");
(new Thread(new Runnable() {
#Override
public void run() {
//TODO: second thread code here
Log.w("tag","2");
}
})).start();
}
})).start();
out put of above:
tag:1
tag:2
but i dont think it's a good idea . just put rest of your job in first Thread

To wait for a thread to complete its execution before moving on, you can use the join() method: docs
Specifically for your problem, you can put thread1.join(), right after the thread1.start() call. The join call will block the calling thread until thread1 is finished with its execution, so that thread2 will be initialized and executed after thread1 is finished.
Alternatively, you can also call thread1.join() in the beginning of the run() method of thread2, so that the main thread won't need to be blocked by the join() call.

Wait for thread to finish and then move to next position

i am trying to display a Toast on the screen and when Toast fades off then move to the next question. I have tried with Thread but cannot seem to manage.
My code:
next.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (getUserSelection()){
position = position + 3;
if (position < questionsArray.size()) {
curName = questionsArray.get(position).getName();
curArray = questionsArray.get(position).getAnswers();
curIscorrect = questionsArray.get(position).getIscorrect();
setupQuestionView(curName, curArray, curIscorrect);
} else {
StringGenerator.showToast(QuestionsActivity.this, "Your score : " + score + "/" + (questionsArray.size() / 3));
}
}else {
StringGenerator.showToast(QuestionsActivity.this, getString(R.string.noanswerselected));
}
}
});
and the getUserSelectionMethod:
private boolean getUserSelection() {
correct = (RadioButton)findViewById(group.getCheckedRadioButtonId());
if (correct == null){
return false;
}else {
correctAnswerText = correct.getText().toString();
if (map.get(correctAnswerText).equals(Constants.CORRECTANSWER)) {
score++;
setCorrectMessage();
return true;
} else {
setWrongMessage();
return true;
}
}
}
private void setCorrectMessage() {
correctToast = new Toast(QuestionsActivity.this);
correctToastView = getLayoutInflater().inflate(R.layout.correct, (ViewGroup) findViewById(R.id.correctRootLayout));
correctText = (TextView)correctToastView.findViewById(R.id.correctTextView);
correctText.setText(getString(R.string.correctAnswer));
correctToast.setDuration(Toast.LENGTH_SHORT);
correctToast.setView(correctToastView);
correctToast.show();
correctThread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
correctToast.cancel();
}
});
correctThread.start();
}
private void setWrongMessage() {
wrongToast = new Toast(QuestionsActivity.this);
wrongToastView = getLayoutInflater().inflate(R.layout.wrong, (ViewGroup) findViewById(R.id.wrongRootLayout));
wrongText = (TextView)wrongToastView.findViewById(R.id.wrongTextView);
wrongText.setText(getString(R.string.wrongAnswer));
wrongToast.setDuration(Toast.LENGTH_SHORT);
wrongToast.setView(wrongToastView);
wrongToast.show();
wrongThread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
wrongToast.cancel();
}
});
wrongThread.start();
}
Any suggestion on how to do this?

You can determine the toast visibility:
toast.getView().getWindowToken()
If the result is null, than your toast isn't visible anymore, and than you can run any code you want.

as stated in this answer you can start a thread that waits the duration of the Toast:
Thread thread = new Thread(){
#Override
public void run() {
try {
Thread.sleep(3500); // 3.5seconds!
// Do the stuff you want to be done after the Toast disappeared
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
Toast.LENGTH_SHORT and Toast.LENGTH_LONG are only flags so you have to either hard code the duration or keep them in a constant. The durations are 3.5s (long) and 2s (short).
If you want to manipulate some of your views, you cannot do this in another thread than the "main" UI thread. So you have to implement a kind of callback/polling mechanism to get notified when the SleepThread has finished.
Check this answer to read about a couple of ways to do this. Probably the easiest of them to understand and implement is this:
After you started your Thread you can check if it is still alive and running by calling thread.isAlive(). In this way you can do a while loop that runs while the thread is running:
// start your thread
while(thread.isAlive()){}
// continue the work. The other thread has finished.
Please note that this is NOT the most elegant way to do this! Check the other possibilities in the answer I've mentioned above for more elegant solutions (especially the last one with the listeners is very interesting and worth reading!)

That's because the Thread class is purely executed in the background and you need to manipulate the view in the Main thread. To solve your issue just replace the Thread with AsynTask.
AsyncTask<Void,Void,Void> a = new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
correctToast.cancel();
}
};
a.execute();
If you look at my code you can see my onPostExecute, this method is called in the Main Thread.

My Error was because i was trying to acess UI Elements through another Thread so modifying the code like this:
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
QuestionsActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
moveToNextQuestion();
}
});
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
thread.start();
did the trick. I hope my answer helps someone!!!

While Loop inside Thread not working?

I have a very simple UI and i need to constantly run a check process, so I am trying to use a Thread with a while loop.
When I run the loop with nothing but a Thread.sleep(1000) command, it works fine, but as soon as I put in a display.setText(), the program runs for a second on the emulator then quits. I cannot even see the error message since it exits so fast.
I then took the display.setText() command outside the thread and just put it directly inside onCreate, and it works fine (so there is no problem with the actual command).
here is my code, and help will be greatly appreciated.
Thank you!
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
on=(Button) findViewById(R.id.bon);
off=(Button) findViewById(R.id.boff);
display=(TextView) findViewById(R.id.tvdisplay);
display2=(TextView) findViewById(R.id.tvdisplay2);
display3=(TextView) findViewById(R.id.tvdisplay3);
stopper=(Button) findViewById(R.id.stops);
stopper.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(boo=true)
{
boo=false;
display3.setText("System Off");
}
else{
boo=true;
}
}
});
Thread x = new Thread() {
public void run() {
while (boo) {
display3.setText("System On");
try {
// do something here
//display3.setText("System On");
Log.d(TAG, "local Thread sleeping");
Thread.sleep(1000);
} catch (InterruptedException e) {
Log.e(TAG, "local Thread error", e);
}
}
}
};
display3.setText("System On");
display3.setText("System On");
x.start();
}

You can't update the UI from a non-UI thread. Use a Handler. Something like this could work:
// inside onCreate:
final Handler handler = new Handler();
final Runnable updater = new Runnable() {
public void run() {
display3.setText("System On");
}
};
Thread x = new Thread() {
public void run() {
while (boo) {
handler.invokeLater(updater);
try {
// do something here
//display3.setText("System On");
Log.d(TAG, "local Thread sleeping");
Thread.sleep(1000);
} catch (InterruptedException e) {
Log.e(TAG, "local Thread error", e);
}
}
}
};
You could also avoid a Handler for this simple case and just use
while (boo) {
runOnUiThread(updater);
// ...
Alternatively, you could use an AsyncTask instead of your own Thread class and override the onProgressUpdate method.

Not 100% certain, but I think it is a case of not being able to modify UI controls from a thread that did not create them?

When you are not in your UI thread, instead of display3.setText("test") use:
display3.post(new Runnable() {
public void run() {
display3.setText("test");
{
});

You should encapsulate this code in an AsyncTask instead. Like so:
private class MyTask extends AsyncTask<Void, Void, Void> {
private Activity activity;
MyTask(Activity activity){
this.activity = activity;
}
protected Long doInBackground() {
while (true){
activity.runOnUiThread(new Runnable(){
public void run(){
display3.setText("System On");
}
});
try{
Thread.sleep(1000);
}catch (InterruptedException e) {
Log.e(TAG, "local Thread error", e);
}
}
}
Then just launch the task from your onCreate method.

In non-UI thread,you can't update UI.In new Thread,you can use some methods to notice to update UI.
use Handler
use AsyncTask
use LocalBroadcast
if the process is the observer pattern,can use RxJava

how to stop infinite loop threads from android service?

i am working with threads in sample application.In my application i have used 3 threads are running in infinite loop.These 3 threads are used in android service class.when i am starting these threads then the threads are running and UI is not allowing until completion of infinite loop.but how can i stop the threads and how can i handle UI?
i have written a service class as follows:
ServiceApp.java
public class ServiceApp extends Service
{
#Override
public IBinder onBind(Intent arg0) {
return null;
}
#Override
public void onCreate() {
super.onCreate();
while(true)
{
Thread child1=new Thread(new Runnable() {
#Override
public void run() {
try {
function1();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
child1.start();
Thread child2=new Thread(new Runnable() {
#Override
public void run() {
try {
function2();
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
});
child2.start();
Thread child3=new Thread(new Runnable() {
#Override
public void run() {
try {
function3();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
child3.start();
Toast.makeText(ServiceApp.this, "All threads started", Toast.LENGTH_SHORT).show();
}
}
public void function1() throws InterruptedException
{
Generic generic=new Generic(); //this for connect to web services
String add=generic.getAdd(10,20);
Log.v("function1", "addition from service"+add);
Thread.sleep(1000);
}
public void function2() throws InterruptedException
{
Generic generic=new Generic(); //this for connect to web services
String sub=generic.getSub(34,20);
Log.v("function2", "subtraction from service"+sub);
Thread.sleep(1000);
}
public void function3() throws InterruptedException
{
Generic generic=new Generic(); //this for connect to web services
String mul=generic.getMul(4, 6);
Log.v("function3", "multipicationn from service"+mul);
Thread.sleep(1000);
}
}
how can i stop child1,child2,child3 threads from activity class?
please any body help me?

Service.onCreate() is executed inside the UI thread. You have an infinite loop there, that continuously creates more and more threads, so UI doesn't get a chance to respond to user's actions. If you actually intend to have so many threads, you need to create another thread that would start the original three.
Activity can communicate with the service either via Binder (you'll need to return an actual implementation instead of null there) or by sending intents, which you can capture and process in Service.onStart()

how to use notify and wait

Can wait/notify be used within one thread?
I'm mean I have a listener and in the moment when that listener gets called I wanna enable a thread to do his work.How could I do that?
UPDATE:My data is written in a database...and is written each time the listener is called.Now the thread that I've created reads that data and sends it somewhere....
Next...I get some other data and do the same thing....The other thread needs to know what was the last data he read it so he can start reading from where he left....
Take a look in here:
using wait and notify within one thread
This is how my problem looks like.Thx
I have the following:
synchronized (syncToken)
{
try {
syncToken.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("MyThread: " + s);
in MyThread....so when I do
MyThread t = new MyThread(syncToken);
t.start();
I put my thread on waiting...yes?
And when I do this:
syncToken.notify();
I get my thread back on track....but the execution of the next line is the one after wait()?
I mean this: System.out.println("MyThread: " + s); ????
When u notify a thred does he continues his execution with the line after wait()???Thx

The following is a simple example of concurrency between two different threads. In the example the main thread start a MyThread thread and every 3 seconds it sets a data to the MyThread instance and then MyThread prints it. The idea is to have a synchronized object that you wait on it and notify in the end of the usage to other threads that they can use it:
Test.java:
package stack;
public class Test {
public static void main (String args[])
{
Object syncToken = new Object();
MyThread t = new MyThread(syncToken);
t.start();
for (int i = 0; i < 10; i++)
{
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
synchronized(syncToken)
{
t.setText("Iteration " + i);
syncToken.notify();
}
}
}
}
MyThread.java:
package stack;
public class MyThread extends Thread{
String s;
Object syncToken;
public MyThread(Object syncToken)
{
this.s = "";
this.syncToken = syncToken;
}
public void run()
{
while(true) // you will need to set some condition if you want to stop the thread in a certain time...
{
synchronized (syncToken)
{
try {
syncToken.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("MyThread: " + s);
}
}
public void setText(String s)
{
this.s = s;
}
}
In this example, the main thread sets a string (every 3 seconds) and the MyThread thread prints it.
Adapt it to your needs, it shouldn't be too hard.

I had similar problem. I created an arbiter used by two threads (in your case it can be listeners thread and your task thread):
listener:
arbiter.waitConsumer();
// prepare data
arbiter.dataLoaded();
task thread:
while(true){
arbiter.waitProducer();
// consume data
arbiter.dataConsumed();
}
arbiter:
public class Arbiter {
private boolean dataLoaded = false;
public synchronized void waitProducer(){
while(!dataLoaded){
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public synchronized void waitConsumer(){
while(dataLoaded){
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public synchronized void dataLoaded(){
dataLoaded = true;
notify();
}public synchronized void dataConsumed(){
dataLoaded = false;
notify();
}}
Listener and task will synchronize themselfes against arbiters monitor. Probably you can call your arbiter queue or pipe and store date for consuming in it?