CODEWITHSUNDEEP
javaandroid
Alex
Alex

Reputation: 41

while(true)loop is forcing my app to crash in Android

I am trying to implement an infinite loop as i want the code to run the follwing code again and again...but it is causing my app to crash...as i am a beginner in this tech, i am not aware of this...any help will be appreciated..thank you..

Here is the Logcat

  06-20 22:04:38.029 22848-22848/sensor.swapni E/AndroidRuntime: FATAL 
  EXCEPTION: main
                                                           Process: 
   sensor.swapni, PID: 22848

   java.lang.OutOfMemoryError: Failed to allocate a 13571692 byte allocation 
   with 7716072 free bytes and 7MB until OOM
                                                               at 
   java.util.ArrayList.add(ArrayList.java:118)
                                                               at 
   android.view.ViewRootImpl$RunQueue.postDelayed(ViewRootImpl.java:8656)
                                                               at 
   android.view.View.postDelayed(View.java:14275)
                                                               at 
   sensor.swapni.Second.onCreate(Second.java:54)
                                                               at 
   android.app.Activity.performCreate(Activity.java:6904)
                                                               at 

android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1136)
                                                               at 
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3266)
                                                               at 
 android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3415)
                                                               at   
android.app.ActivityThread.access$1100(ActivityThread.java:229)
                                                               at 
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821)
                                                               at 
android.os.Handler.dispatchMessage(Handler.java:102)
                                                               at 
android.os.Looper.loop(Looper.java:148)
                                                               at 
android.app.ActivityThread.main(ActivityThread.java:7325)
                                                               at 
java.lang.reflect.Method.invoke(Native Method)
                                                               at

And here is the java code

 while(true) {
        tv1.postDelayed(new Runnable() {
            @Override
            public void run() {
                tv1.setVisibility(View.INVISIBLE);
                tv2.setVisibility(View.VISIBLE);

            }
        }, 1000);
        tv1.postDelayed(new Runnable() {
            @Override
            public void run() {
                tv2.setVisibility(View.INVISIBLE);
                tv1.setVisibility(View.VISIBLE);
            }
        }, 2000);

Upvotes: 0

Views: 1174

Answers (4)

Mark S. Khalil
Mark S. Khalil

Reputation: 157

You Shouldn`t use it inside main thread specially when you are doing operation inside it. You may have to use some thing like that.

   viewModelScope.launch(Dispatchers.IO) {
        while (statues==true){
            if (statue==true){
                delay(500)
                   //ToDo


             }
        }
}

Upvotes: 0

Felix
Felix

Reputation: 2386

Add these two methods to your class:

private void setVisibility1() {
    tv1.setVisibility(View.INVISIBLE);
    tv2.setVisibility(View.VISIBLE);

    tv1.postDelayed(new Runnable() {
        @Override
        public void run() {
            setVisibility2();
        }
    }, 1000);
}

private void setVisibility2() {
    tv1.setVisibility(View.VISIBLE);
    tv2.setVisibility(View.INVISIBLE);

    tv1.postDelayed(new Runnable() {
        @Override
        public void run() {
            setVisibility1();
        }
    }, 1000);
}

And replace the whole loop with one call to this method:

setVisibility1();

setVisibility1 switches the visibility and starts the timer for setVisibility2. When setVisibility2 is executed it changes the visibility again and starts the timer for setVisibility1.

Upvotes: 0

James Maa
James Maa

Reputation: 1794

It is very likely an out of memory issue. Try to set a timer instead of creating tons of new Object.

http://java.sun.com/javase/6/docs/api/java/util/Timer.html

Upvotes: 0

Gabe Sechan
Gabe Sechan

Reputation: 93589

That loop will run thousands of times per second. Each time it runs, it adds at least 4 objects to the heap (2 Runnables, 2 Messages to the handler). Eventually you run out of memory.

If you want to continually do something every 2 seconds, you call postDelayed once on the actual thread, and inside the runnable you call it again. Like this:

   tv1.postDelayed(new Runnable() {
        @Override
        public void run() {
            tv1.setVisibility(View.INVISIBLE);
            tv2.setVisibility(View.VISIBLE);
            tv1.postDelayed(this, 1000);
        }
    }, 1000);

Upvotes: 5

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