Develop Reference

Can my code be suspected of memory leak in android?

I use code like below for periodic execution
but i am suspecting a memory leak
Maybe my code is wrong?
final Handler handler = new Handler();
Runnable runnable = new Runnable() {
public void run() {
if(isRunning)
{
...code
}
handler.postDelayed(this, 5000);
}
};
handler.postDelayed(runnable, 5000);
This is the code that uses another handler
private Handler mHandler;
#Override
protected void onCreate(Bundle savedInstanceState) {
mHandler = new Handler(new Handler.Callback() {
#Override
public boolean handleMessage(#NonNull Message msg) {
return true;
}
});
}

Android How to prevent calling handler.postDelayed multiple times?

I have create a method that after 5 seconds, set ImageView's alpha to 0.4 using handler.postDelayed.
The problem is that the method is called multiple times because of it is located inside of Touch-listener's MotionEvent.ACTION_UP. So I am looking for a method that detect if the handler.postDelayed is active.
private Handler handler;
private Runnable runnable;
private init(){
runnable = new Runnable(){
#Override
public void run(){
ImageView.setAlpha(0.4f);
}
}
}
private void setAlpha(){
handler = new Handler();
handler.postDelayed(runnable,5000);
}
private void cancleHandler(){
handler.removeCallbacks(runnable);
}

1: Keep a reference to the Handler instead of a creating a brand new one each time.
2: Check if the runnable is already posted and don't post a new one if it is.
private Handler handler;
private Runnable runnable;
private init(){
handler = new Handler();
runnable = new Runnable(){
#Override
public void run(){
ImageView.setAlpha(0.4f);
}
}
}
private void setAlpha(){
if (!handler.hasCallbacks(runnable)) {
handler.postDelayed(runnable,5000);
}
}
private void cancleHandler(){
handler.removeCallbacks(runnable);
}

Try to removing the callback before adding another one, and using the same handler instance:
private Handler handler;
private Runnable runnable;
private init(){
handler = new Handler();
runnable = new Runnable(){
#Override
public void run(){
ImageView.setAlpha(0.4f);
}
}
}
private void setAlpha(){
handler.removeCallbacks(runnable);
handler.postDelayed(runnable,5000);
}
private void cancleHandler(){
handler.removeCallbacks(runnable);
}

android implements runnable not working?

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");
}
}

Error inside the class

I have created this class, but there is an error last part saying
"Syntax error on token "(", delete this token" on the "timers.schedule part"
public class refrend
{
Timer timers = new Timer();
final Handler handler = new Handler();
int initial = 1000;
int looper = 6000;
TimerTask task = new TimerTask() {
#Override
public void run() {
handler.post(new Runnable() {
public void run() {
new activityIns().execute();
}
});
}
};
timers.schedule(task, initial, looper);
}
Thanks for your help :)

what you can do is to create a function
public class refrend {
Timer timers = new Timer();
final Handler handler = new Handler();
int initial = 1000;
int looper = 6000;
public void your_Function(){
TimerTask task = new TimerTask() {
#Override
public void run() {
handler.post(new Runnable() {
public void run() {
// new activityIns().execute();
}
});
}
};
timers.schedule(task, initial, looper);
}
}
now you can call that function in you class by your_Functino();
and if you want to use that function out side of class create it object and call
it
refrend object=new refrend();
object.your_Function();

Repeat a Method for specific times in android

Here is a code which I want to repeat 50 times after every 3 seconds. if I am calling this function with 'for' loop or 'while' loop it is not working properly Please give me suggestion.
for (int i = 0; i < 50; i++) {
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
public void run() {
Generate_Ballon();
}
}, delay);
}

You can use CountDownTimer
See Example,
new CountDownTimer(150000, 3000)
{
public void onTick(long millisUntilFinished)
{
// You can do your for loop work here
}
public void onFinish() {
mTextField.setText("done!");
}
}.start();
Here onTick() method will get executed on every 3 seconds.

You should use Handler's postDelayed function for this purpose. It will run your code with specified delay on the main UI thread, so you will be able to update UI controls.
private int mInterval = 5000; // 5 seconds by default, can be changed later
private Handler mHandler;
#Override
protected void onCreate(Bundle bundle) {
...
mHandler = new Handler();
}
Runnable mStatusChecker = new Runnable() {
#Override
public void run() {
updateStatus(); //this function can change value of mInterval.
mHandler.postDelayed(mStatusChecker, mInterval);
}
};
void startRepeatingTask() {
mStatusChecker.run();
}
void stopRepeatingTask() {
mHandler.removeCallbacks(mStatusChecker);
}

private int count = 50;
private Handler handler = new Handler();
private Runnable r = new Runnable() {
public void run() {
Generate_Ballon();
if (--count > 0) {
handler.postDelayed(r, delay);
}
}
};
handler.postDelayed(r, delay);