I have a button that I don't want to be clickable until a certain amount of time has run (say, 5 seconds?) I tried creating a thread like this
continueButtonThread = new Thread()
{
#Override
public void run()
{
try {
synchronized(this){
wait(5000);
}
}
catch(InterruptedException ex){
}
continueButton.setVisibility(0);
}
};
continueButtonThread.start();
But I can't modify the setVisibility property of the button within a different thread. This is the error from the LogCat:
10-02 14:35:05.908: ERROR/AndroidRuntime(14400): android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
Any other way to get around this?
The problem is that you can touch views of your activity only in UI thread. you can do it by using runOnUiThread function. I would like to suggest you to use
handler.postDelayed(runnable, 5000)`
You must update your view from UI-thread. What you are doing is you are updating from non-ui-thread.
Use
contextrunOnUiThread(new Runnable(){
#Override
public void run() {
// TODO Auto-generated method stub
}});
or use handler and signalize hand.sendMessage(msg) when you think is right time to update the view visibility
Handler hand = new Handler()
{
#Override
public void handleMessage(Message msg) {
/// here change the visibility
super.handleMessage(msg);
}
};
You can use the postDelayed method from the View class (A Button is a child of View)
here is simple answer i found
Button button = (Button)findViewBYId(R.id.button);
button .setVisibility(View.INVISIBLE);
button .postDelayed(new Runnable() {
public void run() {
button .setVisibility(View.VISIBLE);
}
}, 7000);
Related
i have a button with onclicklistener that download a picture from internet and update progress-bar in UI thread . when users click on the button for first time , it work correctly , but if the users click on the button for seconds &... when download is not completed , a duplicate process happens .how could i get rid of this problem?
Button btnDownload = (Button) findViewById(R.id.btndownload);
final TextView txtcaption = (TextView) findViewById(R.id.txtcaption);
final ProgressBar progress = (ProgressBar) findViewById(R.id.progress);
btnDownload.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
new Thread(new Runnable() {
OnProgressDownloadListener listener = new OnProgressDownloadListener() {
#Override
public void progressDownload(final int percent) {
new HANDLER.post(new Runnable() {
#Override
public void run() {
progress.setProgress(percent);
txtcaption.setText(percent + " %");
if (percent >= 100) {
txtcaption.setText("completed");
Toast.makeText(activity.this, "download completed", Toast.LENGTH_SHORT).show();
}
}
});
}
};
#Override
public void run() {
//my download manager
FileDownloader.download("address/file", DIR + "/file");
}
}).start();
}
});
}
An easy way to do this would be the following...
First, begin by declaring a thread...
Thread myThread
Then create a simple method that contains the thread you wish to execute when the button is pressed...
private void getPicture()
{
myThread = new Thread()
{
public void run()
{
// Place thread code here...
}
};
myThread.start();
}
Then you can do a simple check when the button is pressed and, if the thread is active, don't call the getPicture method...buttonDownload.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View view)
{
if (myThread.isAlive())
{
// Thread is alive, do not launch again
}
else
{
// Thread is not running so call method...
getPicture();
}
}
});
Have a Thread variable in your class that's initialized to NULL. In your onClickListener, check the value of that variable. If its null, start a new thread and save the value of that thread in the variable. If it isn't, ignore the button press or pop up a downloading toast. Remember to set the variable back to null when your thread is completed.
I'd highly recommend using an AsyncTask for this rather than a thread, it will be cleaner.
I set up event listener, for example: setOnClickListener like this
Button stopBtn = (Button)findViewById(R.id.stop);
stopBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
doMagic();
}
});
I would like to set this listener a timeout event on 10s if button is not pressed. Use case: i have button1 that activates this stopBtn listener for 10s and if timeout comes it becomes deactivated and i need to press button1 to make stopBtn active again.
Im probably doing it wrong:
final Handler myHandler = new Handler();
startBtn = (Button)findViewById(R.id.start);
myHandler.postDelayed(new Runnable() {
public void run() {
startBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.i(TAG,"runned");
}
});
}
}, 10000);
After 10s im still able to click it and that is probably cos event listener is still attached. How can i detach it even if i don't know if its fired or not.
A delayed Runnable posted on a Handler could manage that:
myHandler.postDelayed(new Runnable() {
public void run() {
if(something happened) {
// magic work
} else {
// turn off the event
}
}
, 10000);
You can init the Handler as an instance variable by using this code:
final Handler myHandler = new Handler();
Delayed actions can be arranged by using a Handler. Specifically check the 2 methods: postAtTime(Runnable, long) and postDelayed(Runnable, long).
It is easy to create a Handler, just use its default constructor Handler handler = new Handler() within the Activity.onCreate(Bundle state). Then wrap your desired action into a Runnable and pass to the handler.
I've got an activity that keeps reading words to the user, and using onUtteranceCompleted with textTospeech to display something when the code is completed.
Inside onUtteranceCompleted I have this code to delay a function with a second:
Runnable task = new Runnable() {
public void run() {
//runs on ui
runOnUiThread(new Runnable() {
public void run() {
readWord();
}
});
}
};
worker.schedule(task, 1, TimeUnit.SECONDS);
This seems like it works well, but I think it is causing a problem.
When I rotate the screen of my phone (I guess this starts a new activity).
I hear some words being read in the background. I guess this is because of runOnUiThread() which makes the activity continue in the background.
How could I avoid 2 activities running ? I would prefer if I don't have to stop the screen from rotating on doing some weird patch!
Thank you
EDIT:
public void readWord() {
if (this.readingOnPause) {
return;
}
txtCurrentWord.setText(currentItem[1]);
this.hashAudio.put(TextToSpeech.Engine.KEY_PARAM_UTTERANCE_ID,"word");
this.tts.setLanguage(Locale.US);
this.tts.speak(this.currentItem[1], TextToSpeech.QUEUE_FLUSH,this.hashAudio);
}
EDIT2:
instantiation of worker:
private static final ScheduledExecutorService worker = Executors.newSingleThreadScheduledExecutor();
I would use a Handler instead of runOnUiThread().
For one thing, you're using a Thread that starts another Thread - why?
Secondly, if you create a simple Handler, it should kill itself on the rotate config change. IE:
private Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
// do your background or UI stuff
}
};
Then later use a Thread to call the handler, which will kick off whatever process you want to run on the UI thread:
new Thread() {
#Override
public void run() {
long timestamp = System.currentTimeMillis();
// thread blocks for your 1 second delay
while (System.currentTimeMillis() - timestamp <= 1000) {
// loop
}
handler.sendEmptyMessage(0);
}
}.start();
Ok so this is a fix I've come up with, if someone has a better solution, I'm listening.
I've added android:configChanges="keyboardHidden|orientation" inside the activity in the androidmanifest
2.
and then a function that is called when the screen is rotate:
#Override
public void onConfigurationChanged(Configuration newConfig)
{
super.onConfigurationChanged(newConfig);
setContentView(R.layout.streaming);
initializeUI(); //contains all the findViewByID etc...
}
Can someone explain to me 2 things about the thread code that I finally made almost working the way it should. I want to do a periodic task in the background every x seconds and be able to stop and start it at will. I coded that based on the examples I found, but I'm not sure if I made it in the right way. For the purpose of debugging, the task is displaying a time with custom showTime().
public class LoopExampleActivity extends Activity {
TextView Napis, Napis2;
Button button1,button_start,button_stop;
Handler handler = new Handler();
Boolean tread1_running = true;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Napis = (TextView) findViewById(R.id.textView1);
Napis2 = (TextView) findViewById(R.id.textView2);
button1 = (Button) findViewById(R.id.button1);
button_stop = (Button) findViewById(R.id.button_stop);
button_start = (Button) findViewById(R.id.button_start);
button_stop.setOnClickListener(new OnClickListener() {
#Override
public void onClick (View v) {
tread1_running = false;
}
});
button_start.setOnClickListener(new OnClickListener() {
#Override
public void onClick (View v) {
tread1_running = true;
}
});
thread.start();
}// endof onCreate
final Runnable r = new Runnable()
{
public void run()
{
handler.postDelayed(this, 1000);
showTime(Napis2);
}
};
Thread thread = new Thread()
{
#Override
public void run() {
try {
while(tread1_running) {
sleep(1000);
handler.post(r);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
}
Now the questions are:
1)Will my thread quit forever if I stop it with the stop button?
2)Why can't I start it again with the start_button? If I add the tread.start() in a button, will it crash?
3) I tried a second version when I let the thread run and put a condition into the handler. The only way I can get it to work is to loop conditionaly in the handler by adding an
if (thread1_running) {
handler.postDelayed(this, 2000);
showTime(Napis2);
}
And changing the condition in a thread start to while (true) but then I have an open thread that is running all the time and I start and stop it in a handler, and it posts more and more handlers.
So, finally I get to the point it looks like that:
final Runnable r = new Runnable()
{
public void run()
{
if (thread1_running) handler.postDelayed(this, 1000);
showTime(Napis2);
}
};
Thread thread = new Thread()
{
#Override
public void run() {
try {
while(true) {
sleep(1000);
if (thread1_running) handler.post(r);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
Is the proper way to do that is to start and stop a whole thread? Or that is the best way?
The best way to achieve something like that would be, in my humble opinion, to postDelayed(Runnable, long).
You could do something like this. Class definition:
private Handler mMessageHandler = new Handler();
private Runnable mUpdaterRunnable = new Runnable() {
public void run() {
doStuff();
showTime(Napis2);
mMessageHandler.postDelayed(mUpdaterRunnable, 1000);
}
};
And control true run/stop like this:
To start:
mMessageHandler.postDelayed(mUpdaterRunnable, 1000);
And to stop:
mMessageHandler.removeCallbacks(mUpdaterRunnable);
It's much much simpler, in my humble opinion.
Threads a described by a state machine in java.
When a thread get outs of its run method, it enters in the stopped state and can't be restarted.
You should always stop a thread by getting it out of its run method as you do, it s the proper way to do it.
If you want to "restart the thread", start a new instance of your thread class.
You should better encapsulate your thread and its running field. It should be inside your thread class and the class should offer a public method to swich the boolean. No one cares about your datastructure, hide them. :)
You should consider using runOnUIThread for your runnable, its much easier to use than handlers.
I have a class with a thread and a progress dialog. When the thread stops, the dialog must dismiss. But if the thread stops, the app crashes :S Has anyone an idea whats wrong?
public class Main extends Activity {
public static ProgressDialog LoadingDialog = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LoadingDialog.show(AndroidRSSReader.this, "Laden...", "Even geduld aub...", true);
setContentView(R.layout.main);
startUp();
new Thread(new Runnable(){
public void run() {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
LoadingDialog.dismiss();
}
}).start();
}
LoadingDialog is still null when you call dismiss. You need to make sure and assign it to something (like your progress bar).
LoadingDialog = ProgressDialog.show(AndroidRSSReader.this, "Laden...", "Even geduld aub...", true);
Seems you have problems in dismissing a dialog try using a Handler to perform an action on UI thread :
private Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
// perform logic
if(LoadingDialog!=null)//first check if dialog is not null.This might be a reason for crashing
LoadingDialog.dismiss();
LoadingDialog=null
}
};
& then call it in your activity by simply calling handler.sendEmptyMessage(0);
&you are done.
Additional advice :also have a look at AsyncTask to perform async operation.