How to reduce App's CPU usage in Android phone?

Question

I developed an auto-call application. The app reads a text file that includes a phone number list and calls for a few second, ends the call and then repeats.

My problem is that the app does not send calls after 10~16 hours. I don't know the reason exactly, but I guess that the problem is the CPU usage. My app's CPU usage is almost 50%! How do I reduce CPU usage?

Here is part of source code:

if(r_count.compareTo("0")!=0) {
    while(index < repeat_count) {
        count = 1;
        time_count = 2;

        while(count < map.length) {
           performDial();   //start call
          reject();                   //end call
          finishActivity(1);
          TimeDelay("60");            // wait for 60sec
          count = count + 2;
          time_count = time_count + 2;
          onBackPressed();            // press back button for calling next number
          showCallLog();
          finishActivity(0);
       }
      index++;
}

This is the TimeDelay() method source:

public void TimeDelay(String delayTime) {

    saveTime = System.currentTimeMillis()/1000;
    currentTime = 0;
    dTime = Integer.parseInt(delayTime);

    while(currentTime - saveTime < dTime) {
        currentTime =  System.currentTimeMillis()/1000;

    }

}

TimeDelay() repeats in the while loop for a few times.

Answer 1

The reason it's using 50% of your CPU is that Android apparently won't let it use 100% of the CPU, which a loop like the one in your TimeDelay() ordinarily would. (Or else you have two CPUs and it is in fact using 100% of one CPU.) What you're doing is called a busy wait and it should be obvious why continually checking a condition will use lots of CPU. So don't do that. Use Thread.sleep() instead. Your app will then use no CPU at all during the wait.

Also, for God's sake, why are you passing a string and then parseInting it, rather than just passing an Integer in the first place? :-)

Answer 2

If your method take a long time to finish , especially the while loop. You should put Thread.sleep(50) inside your loop. This makes you processor be able to handle other processes.

Your CPU will be reduced. Not sure but you should try. Hope you get good result.