wait() and notify() in a thread android -

im writing educational mathematics game can choose many operations @ same time, im trying generate 5 questions, runs 5 questions soo fast cant answer them except last questions because stuck there. thought creating thread wait() after creating first question , wait till solved , answered correctly, proceed next question , on... have never used wait , notify before should assign them here got far, gives me exception:

 while (counter < 5) {     thread pause = new thread() {          @override         public void run() {             try {                 this.wait();             } catch (interruptedexception e) {                 e.printstacktrace();             } finally{                  // ops array knowing operation chose,                  // 1 plus , 2 minus                 //generate random number within range of operations length.                 int gen = integer.valueof((int) ((math.random() * (ops.length))));                 log.d("testgen", string.valueof(gen));                  //random operation generated                 int thechosenoperation = ops[gen];                  log.d("test chosen", string.valueof(thechosenoperation));                  switch (thechosenoperation) {                 case 1: // if plus, assign generated numbers , j plus.java                     toast t = toast.maketext(secondactivity.this, "plus", 5000);                     t.show();                     tv.settext("+");                     int = plus.getborder();                     int j = plus.getborder2();                     tv2.settext(string.valueof(i));                     tv3.settext(string.valueof(j));                     answer = plus.getanswer();                     break;                 case 2: //if minus, assign generated numbers , j minus.java                     toast t2 = toast.maketext(secondactivity.this, "minus", 5000);                     t2.show();                     tv.settext("-");                     int i2 = minus.getborder();                     int j2 = minus.getborder2();                     tv2.settext(string.valueof(i2));                     tv3.settext(string.valueof(j2));                     answer = minus.getanswer();                     break;                 }                 b.setonclicklistener(new onclicklistener() {                      public void onclick(view arg0) {                         // todo auto-generated method stub                         if (answer > 0 && answer == integer.parseint(ed.gettext().tostring())) {                             toast t = toast.maketext(secondactivity.this, "true",                                     5000);                             t.show();                             this.notify(); // if answer true notify()                         } else {                             toast t = toast.maketext(secondactivity.this, "false",                                     5000);                             t.show();                         }                      }                 }); // end of clicklistner                 counter++; // counting 5 questions               }//finally         }//run      }; // end of thread     pause.start();  } //end of while loop 

im still new android , threads please patient me. in advance , sorry horrible english.

the usage of thread in context not correct.

• there's main thread or ui thread responsible presenting , managing ui state. if want make changes ui elements textview, button, etc., you'll have in thread. if keep long duration tasks in thread or make thread wait, application become unresponsive , android os show anr dialog. (read more in keeping app responsive)
• threads used when there concurrent tasks executed. in case, tasks not concurrent, rather sequential.

you should think more in terms of event-driven approach application takes decision based on events (like question answered, can used check how many questions have been answered decide whether need generate more questions).