I have a Button in my Activity which, if not clicked within 5 seconds from creating the Activity, I want to crash the App. I tried the following but found out from logging that the OnClickListener code is executed after all other code in onCreate(Bundle) is run. So the boolean is always false when it is checked. How can I fix this?
private Boolean isClicked = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.e("0-isClicked", String.valueOf(isClicked));
setContentView(R.layout.activity_main_map);
ImageView iv = (ImageView) findViewById(R.id.myBTN);
iv.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(getApplicationContext(), MainActivity.class);
isClicked = true;
Log.e("1-isClicked", String.valueOf(isClicked));
startActivity(i);
}
});
Log.e("2-isClicked", String.valueOf(isClicked));
//let app crashes after 5 seconds (5000 milliseconds) if user didn't take action
if (!isClicked) {
Log.e("3-isClicked", String.valueOf(isClicked));
Thread timer = new Thread() {
public void run() {
try {
sleep(5000);
} catch (Exception e) {
e.printStackTrace();
} finally {
throw null;
}
}
};
timer.start();
}
}
And this is what LogCat gives:
E/0-isClicked﹕ false
E/2-isClicked﹕ false
E/3-isClicked﹕ false
E/1-isClicked﹕ true
I would do it the other way around: you crash your app anyway if in the 5 seconds, the user didn't click.
To ease the pain you can use CountdownTimer and do something those lines:
public void onCreate(){
new CountDownTimer(5000, 1000) {
public void onTick(long millisUntilFinished) {
Log.e("isClicked", String.valueOf(isClicked));
}
public void onFinish() {
if(!isClicked) throw null;
}
}.start();
}
You can use a Timer for setting a task to be executed 5 seconds later and in that task you can finish the activity. Create the timer on onCreate()
timer = new Timer(); // Keep the timer (of type Timer) as a member of the activity class so you can access it later
timer.scheduleTask(timerTaskInstance, 5000); // timerTaskInstance is an instance of TimerTask for which you should override the run() method
Now if the button is clicked before the timer times out just cancel the timer on the button's listener method:
timer.cancel();
More info about TimerTask
I think you have to understand when oncreate is runned. Your three first log statments is from onCreate and should be:
E/0-onCreate﹕ false
E/2-onCreate﹕ false
E/3-onCreate﹕ false
See http://www.codelearn.org/android-tutorial/android-activity
Related
I making an app and I would run in to a problem that I can't fix.
I am using Android Studio and I need to make a Button that I have already made. Do more then it already does. I want it to after display a text also close the app. Do you know how I should program that. It would be very helpful. Thanks in advance.
Here is the Java code:
package test.myapplication;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void buttonOnClick(View v) {
Button button=(Button) v;
((Button) v).setText("Correct");
}
public void buttonAnClick(View q) {
Button button=(Button) q;
((Button) q).setText("Niet goed");
}
}
So I have already made the button in XML and told it:
android:onClick="buttonOnClick"
Hope you can help me out!
If you're looking to have something happen afterwards what you're looking for is this:
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
public void run() {
//What you want to happen later
}
}, 1500); //1500 = 1.5 seconds, time in milli before it happens.
Put that in your button's method.
If you want to close your app you should call
finish();
Finish closes out the current activity. If you have other activities on the stack you'd return to them but since you likely only have 1 it should take you out.
Try this.
public void buttonOnClick(View v) {
Button button=(Button) v;
((Button) v).setText("Correct");
new android.os.Handler().postDelayed(new Runnable() {
#Override
public void run() {
finish();
}
},1000); // milliseconds: 1 seg.
}
Check out CountDownTimer
CountDownTimer(30000, 1000) {
public void onTick(long millisUntilFinished) {
mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
}
public void onFinish() {
mTextField.setText("done!");
}
}.start();
If you are trying to get something done with a delay when a button is pressed then do it something like this:
public void buttonOnClick(View v) {
Button button=(Button) v;
button.setText("Correct");
button.postDelayed(new Runnable(){
public void run() {
//runs after 1 second delay on UI thread
}
}, 1000L);
}
If you want to pause then use java.util.concurrent.TimeUnit.
For example:
TimeUnit.SECONDS.sleep(1);
Just put method into your button click function
public void buttonOnClick(View v) {
//call method here
}
If you want to use RxJava
Disposable di = Observable.timer(2, TimeUnit.SECONDS)
.subscribe(timer->{
//next action after 2 seconds
},throwable->{
// throw exception
});
To destroy disposable use, di.dispose();
if Use Runnable and Handler
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
public void run() {
//next action after 2 seconds
}
}, 2*1000);
to stop the handler use, handler.removeCallbacksAndMessages(null);
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.
In my onCreate method in my activity i call a method from an object and pass the methods value as 1 which means to start a timer in the objects class. However I want to stop the timer whenever the app closes, loses focus or someone pressed the back button on their device and exited the app. I tried doing this below my onCreate method with an onPause, onStop, onDestroy and entered the methods value as 2 for the object which means to cancel the timer. However my problem is that whenever someone presses the back button on their device and then goes back in to the app the same timer is running twice because the app did not cancel the timer in the onStop, onPause or onDestroy. Why didn't the onStop, onPause and onDestroy stop the timer and how do i make it stop the timer so two arent running when the app is reopened?
Activity below
Ship mShip = new Ship(0,0,0);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
mShip.timerStart(1);
}
#Override
public void onPause()
{
super.onPause();
mShip.timerStart(2);
}
#Override
public void onStop()
{
super.onStop();
mShip.timerStart(2);
}
#Override
public void onDestroy()
{
super.onDestroy();
mShip.timerStart(2);
}
Ship Class below
public static int counter = 0;
public static int counterPerSec = 5;
TimerClass startTimer = (TimerClass) new TimerClass(2000,1000)
{
#Override
public void onFinish() {
counter += counterPerSec;
this.start();
}
};
public void timerStart(int x) {
if(x == 1)
{
startTimer.start();
}
if(x == 2)
{
startTimer.cancel();
}
}
Timer Class
public class TimerClass extends CountDownTimer {
public TimerClass(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
}
#Override // when timer is finished
public void onFinish() {
this.start();
}
#Override // on every tick of the timer
public void onTick(long millisUntilFinished) {
}
}
I can not see, why your timer is not canceled. But there is another bug in your code: You can not pause and resume a countdown timer by calling resume and start.
If your time gets canceled, you should save the old timer vaules. And if your timer has to be resumed, you can create a new timer with the old timer values. See: Android: How to pause and resume a Count Down Timer?
To your question: Can you debug and check if onPause, onStop, onDestroy is called? Is there any exception thrown? Do you have any compile warnings?
Last important question: How do you know that two timers are running?
Well, I think I can correctly assume that onPause, onStop, and onDestroy are executing, so I would venture to guess that there is a bug in your TimerClass class.
I have two simple activities MainActivity and ThreadActivity. I call ThreadActivity from MainActivity.
The code ofMainActivity:
public class MainActivity extends Activity {
private Button btn;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button)findViewById(R.id.btn2);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, ThreadActivity.class);
startActivity(intent);
}
});
}
}
And the code of ThreadActivity:
public class ThreadActivity extends Activity{
private Thread myThread=null;
Button btn;
int i = 0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.custom);
btn = (Button)findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
runThread();
}
});
}
void runThread(){
myThread = new Thread() {
public void run() {
while (i++ < 1000) {
try {
runOnUiThread(new Runnable() {
#Override
public void run() {
btn.setText("#" + i);
Log.d("Thread", "I am running " + i);
}
});
Thread.sleep(300);
} catch (InterruptedException e) {
e.printStackTrace();
return;
}
}
}
};
myThread.start();
}
}
When I start ThreadActivity I run a simple thread and change button text.
My Problem
When I loose focus from application, i.e when application becomes partially visible, and I come back I am redirected to ThreadActivity and the thread is still running.
When I leave application running and open a new application, and then come back, I am again redirected to ThreadActivity.
The problem is when I press back button, I am being redirected to first activity MainActivity. But instead when back button is being pressed I want my application to exit. In a few words MainActivity should not exist in the stack.
I tried setting android:noHistory="true" for MainActivity but I could not keep the behavior explained in bullet points working. I mean when I pause the application and restore it back, it redirected me to MainActivity instead of ThreadActivity.
Just call finish() when starting the ThreadActivity:
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, ThreadActivity.class);
startActivity(intent);
finish();
}
});
BUT there is a problem with your app. Use a Timer to set the text of the Button! By using a Thread like you do you are creating a memory leak and that is very bad. Try this:
private int i = 0;
private Timer timer;
private final TimerTask timerTask = new TimerTask() {
#Override
public void run() {
btn.post(new Runnable() {
#Override
public void run() {
btn.setText("#" + i++);
}
});
}
};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.custom);
btn = (Button)findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
timer = new Timer();
timer.schedule(timerTask, 300, 300);
}
});
}
#Override
public void onPause() {
super.onPause();
if(timer != null) {
timer.cancel();
}
}
From your comments to other peoples' answers, it seems like you want the ThreadActivity to always be resumed instead of the MainActivity when your thread is running.
Do the thread in a Service - the service will mean your application's VM is likely to be kept alive longer. An app with no foreground activities can be killed off quite quickly (even if it has background threads running).
You need to persist that the thread is running, and the progress (if, in the real code that is applicable). Currently you could persist the value of i in your while loop.
Your application's default launcher activity (MainActivity) will launch when you click on it from your launcher. Check if the persisted value has been set, and act as though the user started the ThreadActivity in onCreate, if you finish() in onCreate, the user won't see any UI from the MainActivity
Depending on what you're actually trying to do, you might be able to resume the thread depending on the progress persisted - in this example, you could start from the persisted value of i (instead of 0).
What I had to is set android:noHistory="true" for MainActivity and in the ThreadActivity I had to add the solution mention by #NeTeInStEiN in this quesiotn
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
moveTaskToBack(true);
return true;
}
return super.onKeyDown(keyCode, event);
}
I defined a splashscreen the following way:
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ExceptionHandler.register(this);
setFullscreen();
splashScreen();
}
private void splashScreen() {
runOnUiThread(new Runnable() {
#Override
public void run() {
setContentView(R.layout.splashscreen);
splash = (ImageView) findViewById(R.id.splashscreenLayer);
startSplashTime = new Date();
}
});
new LoadingThread().start();
}
private class LoadingThread extends Thread {
#Override
public void run() {
checkNetwork();
}
}
Somewhere at specific conditions in the checkNetwork() method, the stopSplash method is called:
public void stopSplash() {
Message msg = new Message();
msg.what = STOPSPLASH;
Date endSplashTime = new Date();
long time = endSplashTime.getTime() - startSplashTime.getTime();
System.out.println("Time Splashscreen was displayed: " + time);
if (time < SPLASH_MIN_TIME) {
long delay = SPLASH_MIN_TIME - time;
System.out.println("Delay Splashscreen for: " + delay);
try {
Thread.sleep(delay);
} catch (InterruptedException e) {
e.printStackTrace();
}
splashHandler.sendMessage(msg);
} else {
System.out.print("Show Splashscreen now");
splashHandler.sendMessage(msg);
}
}
private Handler splashHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case STOPSPLASH:
splash.setVisibility(View.GONE);
break;
}
super.handleMessage(msg);
}
};
The problem is, sometimes (maybe 1 of 10) if I started the app directly from Eclipse, the Splashscreen isn't showed, but instead just a black screen.
Other problem: if i restart the app, e.g. after onDestroy() was called after clicking the back button on the device, the Splashscreen is almost never shown.
Any hints why?
My assumption: could it be, that the LoadingThread starts "faster" than the Runnable, and so the network staff is done before the Splashscreen is set?
You might try using a CountdownTimer in your implementation. On your first activity, start a CountdownTimer that checks in onTick() every so often for a synchronized boolean finishedLoading with some kind of timeout in onFinish() (15 seconds or something), while your loading is done in another thread that sets finishedLoading to true when it is finished.
Maybe the splash screen isnt being terminated before the v=next activity starts.. just a thought..