CODEWITHSUNDEEP
androidonstart
Fotis Emery
Fotis Emery

Reputation: 15

Is it possible to run an Android app without onStart()?

I am totally new to Android and I'm just learning about the Activity life cycle.
In all the apps that I have made so far to practice, I hadn't been using the onStart() method (mostly because I didn't know of it) and the apps worked perfectly fine.

Why though did they work perfectly fine?
And when do I have to explicitly write an onStart() method in my app then?

Upvotes: 0

Views: 262

Answers (2)

Joaquin Sainz de la Maza
Joaquin Sainz de la Maza

Reputation: 123

That´s because your activities are subclasses from Activity or AppCompatActivity. You don´t need to override this method to make the activity work. If you want to know when to use that method you can check this post:

android: when to use onStart(), onStop()?

Upvotes: 3

Hasan Bou Taam
Hasan Bou Taam

Reputation: 4035

On create

Is called when the activity is created and then never called again. Unless you open the activity again.

On start

Is called when the activity is created and also called again every time the activity is resumed (if you return to it using back button).

example

lets say we want to show a toast message we will call it "message".

First case

if we want to show "message" only when we create the activity we add the toast in Oncreate, and this is what happens

If you open activity A ----> Oncreate will be called -----> "message" is shown-----> Onstart called -----> nothing happens

If you open from A another activity B and press back ----> onCreate is ignored -----> onStart is triggered -----> nothing happens.

((SO MESSAGE IS SHOWN ONLY ONCE WHEN YOU CREATE THE ACTIVITY)).

Second case

If we want to show "message" each time activity is shown or everytime it becomes visible, we add the toast in onStart, and this what happens:

If you open activity A ----> Oncreate will be called -----> nothing happens-----> Onstart called -----> "message" shown

If you open from A another activity B and press back ----> onCreate is ignored -----> onStart is triggered -----> "message" shown again.

((SO HERE MESSAGE IS SHOWN WHEN WE CREATE ACTIVITY AND WHEN WE GO BACK TO IT)).

This is why on start is not always important to use for app to function.

Upvotes: 1

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