Back button and refreshing previous activity

Question

If we have two activities:

1. List of files and last modified time
2. File editing activity

A user selects a file from the list and is taken to the file editing activity. When done editing, the user presses the back button to return to the file list.

The list is not reloaded and therefore an incorrect value is displayed for the just edited files modified time.

What is the proper method of causing the file list to refresh after the back button is pressed?

This example assumes that no database is being used, just an ArrayAdapter.

Distrain

onRestart() should work better. onResume() will be called twice, and onRestart() will be called only when you press the back button. – Bannerman

Answer 1

I think onRestart() works better for this.

@Override
public void onRestart() { 
    super.onRestart();
    //When BACK BUTTON is pressed, the activity on the stack is restarted
    //Do what you want on the refresh procedure here
}

You could code what you want to do when the Activity is restarted (called again from the event 'back button pressed') inside onRestart().

For example, if you want to do the same thing you do in onCreate(), paste the code in onRestart() (eg. reconstructing the UI with the updated values).

Bannerman

This is trivial, but I have to say it: obviously it'd be better to move your onCreate() code into a separate method that you then invoke from both onCreate() as well as onRestart() instead of copy pasting it. – Malave

You can also use onCreate() only to inflate views and instantiate global variables and use onStart() to assign/(re)set them. Thus your init() (or whatever you want to call it) will be called whenever the activity starts; i.e. after onCreate() or after onRestart(). – Motile

This is really useful if you need your activities' ViewModel to be reinitialized. Lets it fetch from database again, setup instance variables... – Byproduct

Answer 2

in main:

@Override
public void onRestart()
{
    super.onRestart();
    finish();
    startActivity(getIntent());
}

Meagre

I am guessing this goes to the current activity and not the previous activity? – Akers

I had the same issue, except mine was a Fragment not Activity. Thus, I follow advice here and it worked: #35040012 – Fuchs

Answer 3

I would recommend overriding the onResume() method in activity number 1, and in there include code to refresh your array adapter, this is done by using [yourListViewAdapater].notifyDataSetChanged();

Read this if you are having trouble refreshing the list: Android List view refresh

Everard

Answer 4

 @Override
protected void onRestart() {
    super.onRestart();
    finish();
    overridePendingTransition(0, 0);
    startActivity(getIntent());
    overridePendingTransition(0, 0);
}

In previous activity use this code. This will do a smooth transition and reload the activity when you come back by pressing back button.

Markham

Can you add some description to the code and thank you for the post. – Electrotechnology

this works fine, but it is not so smooth a normal transition between activities, but can live with that – Stott

Answer 5

If you want to refresh previous activity, this solution should work:

In previous activity where you want to refresh:

@Override
public void onRestart()
{
    super.onRestart();
    // do some stuff here
}

Mokpo

Answer 6

private Cursor getAllFavorites() {
    return mDb.query(DocsDsctnContract.DocsDsctnEntry.Description_Table_Name,
            null,
            null,
            null,
            null,
            null,
            DocsDsctnContract.DocsDsctnEntry.COLUMN_Timest);
}
@Override
public void onResume()
{  // After a pause OR at startup
    super.onResume();
    mAdapter.swapCursor(getAllFavorites());
    mAdapter.notifyDataSetChanged();

}

public void swapCursor(Cursor newCursor){
    if (mCursor!=null) mCursor.close();
    mCursor = newCursor;
    if (newCursor != null){
        mAdapter.notifyDataSetChanged();
    }
}

I just have favorites category so when i click to the item from favorites there appear such information and if i unlike it - this item should be deleted from Favorites : for that i refresh database and set it to adapter(for recyclerview)[I wish you will understand my problem & solution]

Heloise

consider adding some explaination – Cthrine

Answer 7

If not handling a callback from the editing activity (with onActivityResult), then I'd rather put the logic you mentioned in onStart (or possibly in onRestart), since having it in onResume just seems like overkill, given that changes are only occurring after onStop.

At any rate, be familiar with the Activity lifecycle. Plus, take note of the onRestoreInstanceState and onSaveInstanceState methods, which do not appear in the pretty lifecycle diagram.

(Also, it's worth reviewing how the Notepad Tutorial handles what you're doing, though it does use a database.)

Vigesimal

Answer 8

The think best way to to it is using

Intent i = new Intent(this.myActivity, SecondActivity.class); 
startActivityForResult(i, 1);

Schaab

Answer 9

Try This

 public void refreshActivity() {
    Intent i = new Intent(this, MainActivity.class);
    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    startActivity(i);
    finish();

}

or in Fragment

  public void refreshActivity() {
    Intent i = new Intent(getActivity(), MainActivity.class);
    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    startActivity(i);
    finish();

}

And Add this method to your onBackPressed() like

  @Override
public void onBackPressed() {      
        refreshActivity();
        super.onBackPressed();
    }
}

Thats It...

Chipper

Answer 10

@Override
public void onBackPressed() {
    Intent intent = new Intent(this,DesiredActivity.class);
    startActivity(intent);
    super.onBackPressed();
}

Decalcify

This question is some years old and the provided answer was flagged for review as a Low Quality Post. Here are some guidelines for How do I write a good answer?. There are other answers that provide the OP's question, and they were posted some time ago. When posting an answer, please make sure you add either a new solution, or a substantially better explanation, especially when answering older questions. – Particularism

onBackPressed is deprecated – Stott