I try to implement a thread that runs next to the main thread, this thread isexecuted in 20 seconds, I need that after finishing the thread again it executes again in a continuous way.
With this code the thread is executed once, but how do I do it to run again?
public class MainActivity extends AppCompatActivity {
.
.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate( savedInstanceState );
setContentView( R.layout.activity_main );
.
.
treadTimer();
}
private void treadTimer(){
new Thread(new Runnable() {
#Override
public void run() {
for(int i=1; i<= 20; i++){
UnSegundo();
}
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getBaseContext(), "Tarea Larga Finalizada", Toast.LENGTH_SHORT).show();
}
});
}
}).start();
}
private void UnSegundo(){
try{
Thread.sleep(1000);
}catch (InterruptedException e){}
}
}
This is one of the ways
Handler handler = new Handler();
private Runnable runnable = new Runnable() {
#override
public void run() {
doYourThing();
handler.post(this, 20000);
}
}
handler.post(runnable);
Related
TextView output;
int i;
Random random=new Random();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
output=findViewById(R.id.textView);
new Thread(new mythread()).start();
}
class mythread implements Runnable{
#Override
public void run() {
try {
while(true) {
i = random.nextInt(100);
output.setText(i + "");
Thread.sleep(500);
}
}catch (Exception e){}
}
}
}
it just showing one number in text view
but requirement is ,it should generate random number and keep updating textview after 500ms
Thank You!
The main problem, in your code, is that you can update UI only in the main thread and you are using a custom thread.
The second problem is that you are using Thread.sleep that is a very bad practise.
I suggest you to use Handler
Handler handler = new Handler();
Runnable runnable = new Runnable() {
#Override
public void run() {
Log.d("Handler", "Running Handler");
handler.postDelayed(this, 500);
}
}
handler.postDelayed(runnable, 0);
and here the kotlin version
var handler = Handler()
var runnable = object : Runnable {
override fun run() {
Log.d("Handler", "Running Handler");
handler.postDelayed(this, 500)
}
}
handler.postDelayed(runnable, 500)
Try this, I think it will solved your problem.
public class MainActivity extends AppCompatActivity {
private Random random;
private Handler handler;
private TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = findViewById(R.id.tv_number);
displayRandomNumber();
}
/**
* Display random number in text view
*/
private void displayRandomNumber()
{
random = new Random();
handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
int value = random.nextInt();
textView.setText(String.valueOf(value));
handler.postDelayed(this,2000);
}
}, 2000);
}
}
this is a simple code to understand the runnable .I tried but not working . can you guys help me pls this is my code
public class Autostart extends activity implements Runnable {
#override
public void run (){
System.out.println ("message");
}
}
}
this not printing any statements
If you are using an Activity, you need to write your code inside Activity lifecycle methods. onCreate() is called when the Activity is created. So starting your Runnable here would be the correct way to do it.
#Override
public void onCreate(Bundle savedInstanceState) {
Handler handler = new Handler();
final Runnable r = new Runnable() {
public void run() {
System.out.println ("message");
}
};
handler.postDelayed(r, 1000);
}
You have to create a Thread object and call start() using that object.
Thread t = new Thread(this);
t.start();
Or Just use Handler
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
// Do Something here
}
}, 5000);
You can use below code to print a value after regular interval of time
public void callAsynchronousTask() {
final Handler handler = new Handler();
timer = new Timer();
TimerTask doAsynchronousTask = new TimerTask() {
#Override
public void run() {
handler.post(new Runnable() {
public void run() {
try {
Log.e("on print timee", your value);
} catch (Exception e) {
// TODO Auto-generated catch block
}
}
});
}
};
timer.schedule(doAsynchronousTask, 0, 1000); // will execute after 1 sec
}
Hope this will help you
I found a similar solution to Swayam (android implements runnable not working?), however another handler.postDelayed reference within run() was required;
public void onCreate(
...
final Handler handler = new Handler();
final Runnable r = new Runnable()
{
public void run()
{
Log.i(TAG, "message");
handler.postDelayed(this, 1000);
...
}
};
handler.postDelayed(r, 1000);
Try following code
Handler mainThreadhandler = new Handler(getMainLooper());
mainThreadhandler.post(new Runnable(){
public void run(){
// UI work
}
});
public class Autostart extends activity implements Runnable {
Thread = thread;
#override
public void onCreate() {
thread = new Thread(this);
thread.start();
}
#override
public void run (){
System.out.println ("message");
}
}
I am trying to create one application which checks battery status every one minute and update the UI with the battery Level.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
batteryPercent = (TextView) this.findViewById(R.id.battery);
while (true) {
runOnUiThread(mRunnable);
}
}
private Runnable mRunnable = new Runnable() {
#Override
public void run() {
getBatteryPercentage();
try {
Thread.sleep(60000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
`getBatteryPercentage()1 update a text view on UI.
When I call getBatteryPercentage() only once the code works fine, but when I try to run it in a loop like above, after few seconds I get Application Not Responding(ANR).
Is there any way to make the app wait for 60 seconds without getting ANR?
Don't do it with Sleep. Use a CountDownTimer instead.
CountDownTimer _timer;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
batteryPercent = (TextView) this.findViewById(R.id.battery);
_timer = new CountDownTimer(Long.MAX_VALUE, 60000) {
#Override
public void onTick(long millisUntilFinished)
{
getBatteryPercentage();
}
#Override public void onFinish() {}
};
_timer.start();
Don't forget to call _timer.cancel() before the Activity exits.
You can use Handler.postDelayed for this.
Handler handler = new Handler();
private Runnable mRunnable = new Runnable() {
#Override
public void run() {
getBatteryPercentage();
handler.postDelayed(mRunnable, 60000);
}
}
And then:
handler.postDelayed(mRunnable, 60000);
if you do something in android uithread more than 5 seconds,the application will show ANR toast.
you should do while loop in another thread,and use callback to refresh ui.you can do it like this:
new Thread(new Runnable(){
public void run(){
try{
Thread().sleep(6*1000);
updateUI();
}catch( Exception e){
e.print***();
}}}).start();
private void updateUI(){
runOnUiThread(new Runnable(){
getBatteryPercentage();
});
}
public class ProgressBarTest extends Activity {
private int progress;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.progress_bar);
final Handler handler = new Handler();
progress = 0;
final ProgressBar pb = (ProgressBar) findViewById(R.id.progressbar);
new Thread(new Runnable() {
public void run() {
while (progress < 10) {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
progress++;
}
handler.post(new Runnable() {
#Override
public void run() {
pb.setVisibility(View.GONE);
}
});
}
}).start();
}
}
Why can't I just put the pb.setVisibility(View.GONE) in the first Runnable inner class? Like this: The program crashes if I write it this way.
new Thread(new Runnable() {
public void run() {
while (progress < 10) {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
progress++;
pb.setVisibility(View.GONE);
}
}
}
The program crashes when the setVisibility statement is executed.
You cannot update ui from a thread. Ui should be updated on the ui thread.
In the second one you are setting the visibility of progressbar inside the threads runs method. Hence it crashes. So you use handler to set the visibility of progress bar in the the first
To know more about handlers.
http://developer.android.com/reference/android/os/Handler.html
I'm trying to use the UI-Thread, so I've written a simple test activity. But I think I've misunderstood something, because on clicking the button - the app does not respond anymore
public class TestActivity extends Activity {
Button btn;
int i = 0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btn = (Button)findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
runThread();
}
});
}
private void runThread(){
runOnUiThread (new Thread(new Runnable() {
public void run() {
while(i++ < 1000){
btn.setText("#"+i);
try {
Thread.sleep(300);
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}));
}
}
Below is corrected Snippet of runThread Function.
private void runThread() {
new Thread() {
public void run() {
while (i++ < 1000) {
try {
runOnUiThread(new Runnable() {
#Override
public void run() {
btn.setText("#" + i);
}
});
Thread.sleep(300);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}.start();
}
Just wrap it as a function, then call this function from your background thread.
public void debugMsg(String msg) {
final String str = msg;
runOnUiThread(new Runnable() {
#Override
public void run() {
mInfo.setText(str);
}
});
}
You have it back-to-front. Your button click results in a call to runOnUiThread(), but this isn't needed, since the click handler is already running on the UI thread. Then, your code in runOnUiThread() is launching a new background thread, where you try to do UI operations, which then fail.
Instead, just launch the background thread directly from your click handler. Then, wrap the calls to btn.setText() inside a call to runOnUiThread().
runOnUiThread(new Runnable() {
public void run() {
//Do something on UiThread
}
});
There are several techniques using of runOnUiThread(), lets see all
This is my main thread (UI thread) called AndroidBasicThreadActivity and I'm going to update it from a worker thread in various ways -
public class AndroidBasicThreadActivity extends AppCompatActivity
{
public static TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_android_basic_thread);
textView = (TextView) findViewById(R.id.textview);
MyAndroidThread myTask = new MyAndroidThread(AndroidBasicThreadActivity.this);
Thread t1 = new Thread(myTask, "Bajrang");
t1.start();
}
}
1.) By passing Activity's instance as an argument on worker thread
class MyAndroidThread implements Runnable
{
Activity activity;
public MyAndroidThread(Activity activity)
{
this.activity = activity;
}
#Override
public void run()
{
//perform heavy task here and finally update the UI with result this way -
activity.runOnUiThread(new Runnable()
{
#Override
public void run()
{
AndroidBasicThreadActivity.textView.setText("Hello!! Android Team :-) From child thread.");
}
});
}
}
2.) By using View's post(Runnable runnable) method in worker thread
class MyAndroidThread implements Runnable
{
Activity activity;
public MyAndroidThread(Activity activity)
{
this.activity = activity;
}
#Override
public void run()
{
//perform heavy task here and finally update the UI with result this way -
AndroidBasicThreadActivity.textView.post(new Runnable()
{
#Override
public void run()
{
AndroidBasicThreadActivity.textView.setText("Hello!! Android Team :-) From child thread.");
}
});
}
}
3.) By using Handler class from android.os package
If we don't have the context (this/ getApplicationContext()) or Activity's instance (AndroidBasicThreadActivity.this) then we have to use Handler class as below -
class MyAndroidThread implements Runnable
{
Activity activity;
public MyAndroidThread(Activity activity)
{
this.activity = activity;
}
#Override
public void run()
{
//perform heavy task here and finally update the UI with result this way -
new Handler(Looper.getMainLooper()).post(new Runnable() {
public void run() {
AndroidBasicThreadActivity.textView.setText("Hello!! Android Team :-) From child thread.");
}
});
}
}
If using in fragment then simply write
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
// Do something on UiThread
}
});
We use Worker Thread to make Apps smoother and avoid ANR's. We may need to update UI after the heavy process in worker Tread.
The UI can only be updated from UI Thread. In such cases, we use Handler or runOnUiThread both have a Runnable run method that executes in UI Thread.
The onClick method runs in UI thread so don't need to use runOnUiThread here.
Using Kotlin
While in Activity,
this.runOnUiThread {
// Do stuff
}
From Fragment,
activity?.runOnUiThread {
// Do stuff
}
Using Java,
this.runOnUiThread(new Runnable() {
void run() {
// Do stuff
}
});
For fragment use that:
requireActivity().runOnUiThread(() -> {
//your code logic
});
For activity use that:
runOnUiThread(() -> {
//your code logic
});
runOnUiThread is used in a way the UI can be updated with our background thread. For more: https://www.tutorialspoint.com/how-do-we-use-runonuithread-in-android
thy this:
#UiThread
public void logMsg(final String msg) {
new Handler(Looper.getMainLooper()).post(new Runnable() {
#Override
public void run() {
Log.d("UI thread", "I am the UI thread");
}
});
}
You can use from this sample :
In the following example, we are going to use this facility to publish the result from a
synonym search that was processed by a background thread.
To accomplish the goal during the OnCreate activity callback, we will set up
onClickListener to run searchTask on a created thread.
When the user clicks on the Search button, we will create a Runnable anonymous
class that searches for the word typed in R.id.wordEt EditText and starts the
thread to execute Runnable.
When the search completes, we will create an instance of Runnable SetSynonymResult
to publish the result back on the synonym TextView over the UI thread.
This technique is sometime not the most convenient one, especially when we don't
have access to an Activity instance; therefore, in the following chapters, we are
going to discuss simpler and cleaner techniques to update the UI from a background
computing task.
public class MainActivity extends AppCompatActivity {
class SetSynonymResult implements Runnable {
String synonym;
SetSynonymResult(String synonym) {
this.synonym = synonym;
}
public void run() {
Log.d("AsyncAndroid", String.format("Sending synonym result %s on %d",
synonym, Thread.currentThread().getId()) + " !");
TextView tv = (TextView) findViewById(R.id.synonymTv);
tv.setText(this.synonym);
}
}
;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button search = (Button) findViewById(R.id.searchBut);
final EditText word = (EditText) findViewById(R.id.wordEt);
search.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Runnable searchTask = new Runnable() {
#Override
public void run() {
String result = searchSynomim(word.getText().toString());
Log.d("AsyncAndroid", String.format("Searching for synonym for %s on %s",
word.getText(), Thread.currentThread().getName()));
runOnUiThread(new SetSynonymResult(result));
}
};
Thread thread = new Thread(searchTask);
thread.start();
}
});
}
static int i = 0;
String searchSynomim(String word) {
return ++i % 2 == 0 ? "fake" : "mock";
}
}
Source :
asynchronous android programming Helder Vasconcelos
This is how I use it:
runOnUiThread(new Runnable() {
#Override
public void run() {
//Do something on UiThread
}
});
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
gifImageView = (GifImageView) findViewById(R.id.GifImageView);
gifImageView.setGifImageResource(R.drawable.success1);
new Thread(new Runnable() {
#Override
public void run() {
try {
//dummy delay for 2 second
Thread.sleep(8000);
} catch (InterruptedException e) {
e.printStackTrace();
}
//update ui on UI thread
runOnUiThread(new Runnable() {
#Override
public void run() {
gifImageView.setGifImageResource(R.drawable.success);
}
});
}
}).start();
}
Try this: getActivity().runOnUiThread(new Runnable...
It's because:
1) the implicit this in your call to runOnUiThread is referring to AsyncTask, not your fragment.
2) Fragment doesn't have runOnUiThread.
However, Activity does.
Note that Activity just executes the Runnable if you're already on the main thread, otherwise it uses a Handler. You can implement a Handler in your fragment if you don't want to worry about the context of this, it's actually very easy:
// A class instance
private Handler mHandler = new Handler(Looper.getMainLooper());
// anywhere else in your code
mHandler.post(<your runnable>);
// ^ this will always be run on the next run loop on the main thread.