1. Introduction

In this post, I would demo an example of how to do daily task by using Timer.

2. Environment

  • JDK 1.8

3. Example

Timer myTimer = new Timer(); // create a timer instance.

Calendar calendar = Calendar.getInstance(); // create a canlendar to get the start time

calendar.set(Calendar.HOUR_OF_DAY, 7);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
Date time = calendar.getTime();

myTimer.schedule(new TimerTask() {
	public void run() {
	 try {
	     //do my real task here.

	 } catch (Exception e) {
	 }}},time,24*3600*1000);//every day at 7am.

Here we called the Timer’s schedule method, it has the detailed documents as follows:

public void schedule (TimerTask task, Date firstTime, long period) Schedules the specified task for repeated fixed-delay execution, beginning at the specified time. Subsequent executions take place at approximately regular intervals, separated by the specified period.

In fixed-delay execution, each execution is scheduled relative to the actual execution time of the previous execution. If an execution is delayed for any reason (such as garbage collection or other background activity), subsequent executions will be delayed as well. In the long run, the frequency of execution will generally be slightly lower than the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate). As a consequence of the above, if the scheduled first time is in the past, it is scheduled for immediate execution.

Fixed-delay execution is appropriate for recurring activities that require “smoothness.” In other words, it is appropriate for activities where it is more important to keep the frequency accurate in the short run than in the long run. This includes most animation tasks, such as blinking a cursor at regular intervals. It also includes tasks wherein regular activity is performed in response to human input, such as automatically repeating a character as long as a key is held down.

4. Summary

It’s very easy to do this scheduler job in android with Timer!