I want to make a pause between two lines of code, Let me explain a bit:
-> the user clicks a button (a card in fact) and I show it by changing the background of this button:
thisbutton.setBackgroundResource(R.drawable.icon);
-> after let's say 1 second, I need to go back to the previous state of the button by changing back its background:
thisbutton.setBackgroundResource(R.drawable.defaultcard);
-> I've tried to pause the thread between these two lines of code with:
try { Thread.sleep(1000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); }
However, this does not work. Maybe it's the process and not the Thread that I need to pause?
I've also tried (but it doesn't work):
new Reminder(5);
With this:
public class Reminder { Timer timer; public Reminder(int seconds) { timer = new Timer(); timer.schedule(new RemindTask(), seconds*1000); } class RemindTask extends TimerTask { public void run() { System.out.format("Time's up!%n"); timer.cancel(); //Terminate the timer thread } } }
How can I pause/sleep the thread or process?
time.The sleep() function suspends execution of the current thread for a given number of seconds. In case of single-threaded programs, sleep() suspends execution of the thread and process.
sleep() method can be used to pause the execution of current thread for specified time in milliseconds. The argument value for milliseconds can't be negative, else it throws IllegalArgumentException .
A thread is a lightweight sub-process, it going to do background operations without interrupt to ui. This example demonstrate about How to use thread. sleep() in android. Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Navigate to and open Settings, and then tap Battery and device care. Tap Battery, and then tap Background usage limits. The following settings will be available: Put unused apps to sleep: If you haven't used an app in a while, it will automatically be put to sleep.
One solution to this problem is to use the Handler.postDelayed() method. Some Google training materials suggest the same solution.
@Override public void onClick(View v) { my_button.setBackgroundResource(R.drawable.icon); Handler handler = new Handler(); handler.postDelayed(new Runnable() { @Override public void run() { my_button.setBackgroundResource(R.drawable.defaultcard); } }, 2000); }
However, some have pointed out that the solution above causes a memory leak because it uses a non-static inner and anonymous class which implicitly holds a reference to its outer class, the activity. This is a problem when the activity context is garbage collected.
A more complex solution that avoids the memory leak subclasses the Handler
and Runnable
with static inner classes inside the activity since static inner classes do not hold an implicit reference to their outer class:
private static class MyHandler extends Handler {} private final MyHandler mHandler = new MyHandler(); public static class MyRunnable implements Runnable { private final WeakReference<Activity> mActivity; public MyRunnable(Activity activity) { mActivity = new WeakReference<>(activity); } @Override public void run() { Activity activity = mActivity.get(); if (activity != null) { Button btn = (Button) activity.findViewById(R.id.button); btn.setBackgroundResource(R.drawable.defaultcard); } } } private MyRunnable mRunnable = new MyRunnable(this); public void onClick(View view) { my_button.setBackgroundResource(R.drawable.icon); // Execute the Runnable in 2 seconds mHandler.postDelayed(mRunnable, 2000); }
Note that the Runnable
uses a WeakReference to the Activity, which is necessary in a static class that needs access to the UI.
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