Jumping progress bar or running process indicator?

1. When not to use a progress bar?
2. When to use progress indicator?
3. What is the use of progress bar?
4. When to show spinner?

When not to use a progress bar?

Don't create a progress bar that fills to 90% in a few seconds and takes minutes for the last 10% to load. Make it even and specify the correct time remaining. Make sure that the progress bar is constantly moving. A loading bar that stagnates for a long time will give the impression that the platform crashed.

When to use progress indicator?

Use a progress indicator for any action that takes longer than about 1 second. For anything that takes less than 1 second to load, it is distracting to use an animation.

What is the use of progress bar?

Progress bars are used to show progress of a task. For example, when you are uploading or downloading something from the internet, it is better to show the progress of download/upload to the user. In android there is a class called ProgressDialog that allows you to create progress bar.

When to show spinner?

Spinners are best used when you aren't quite sure how long an action is going to take to complete. This could be when waiting for something to buffer or for a user to regain a lost connection.