CODEWITHSUNDEEP
androidandroid-activity
AuTi
AuTi

Reputation: 69

Refresh activity and re-open

This is my first post, so please be nice :) I have a question and no one gave the answer in the post I've seen.

My app has a list and a button to open an activity, this activity creates a new item to show in the list of the previous activity when pressing the button Create.

How can I do this?

This is the code I made for the first button:

intent = new Intent(this.getBaseContext(), NewTestActivity.class);
this.finish();
startActivity(intent);

and this is the code to go back an refresh:

Intent intent = new Intent(getBaseContext(), TestListActivity.class);                       
startActivity(intent);

But the code to goback is useful, because the activity don't refresh. I have to call the new activity in a diferent way? Or go back to previus activity in a diferent way? Or go back normally and refresh the activity when I'm back in the previus activity?

Well...this is all. Sorry for my bad english and, if this question has been answered in another thread, give me the link to read, because I can't find it :)

PS: I started with android in December.

Thanks for your help.

Upvotes: 3

Views: 5725

Answers (2)

Jave
Jave

Reputation: 31846

Before getting to a real answer, I'd like to show some improvements to your code. First, when creating an Intent (or when you need a context in general) from an Activity there is no need to call getBaseContext(), you can just use this:

intent = new Intent(this, NewTestActivity.class);

Second, android is good at handling Activities, you do not have to close your first activity manually with finish(). Android will automatically pause or stop your first activity and bring it back when you return to it.

Third, in your case you might want to use startActivityForResult() instead of startActivity() for reasons I will explain below.
This will make your code look like the following: 

private static final int MY_REQUEST_CODE = 33487689; //put this at the top of your Activity-class, with any unique value.
intent = new Intent(this, NewTestActivity.class);
startActivityForResult(intent, MY_REQUEST_CODE);

Now, the startActivityForResult() starts an activity and waits for a result from that new Activity. When you call finsih() in the new Activity you will end up in the first Activitys onActivityResult()-method, with data supplied from the new Activty that is now closed: 

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if(requestCode != MY_REQUEST_CODE) return; //We got a result from another request, so for this example we can return.
    if(resultCode != RESULT_OK) return; //The user aborted the action, so we won't get any data.
    //After the above if-statements we know that the activity that gives us a result was requested with the correct request code, and it's action was successful, we can begin extracting the data, which is in the data-intent:
    Item item = (Item) data.getSerializableExtra("customData"); //casts the data object to the custom Item-class. This can be any class, as long as it is serializable. There are many other kinds of data that can be put into an intent, but for this example a serializable was used.
    itemList.add(item); //This is the list that was specified in onCreate()
    //If you use an Adapter, this is the place to call notifyDataSetChanged();
}

For this all to work, we need to do some things in the second Activity: When the item has been created, we must set a result:

//We begin by packing our item in an Intent (the Item class is an example that is expected to implement Serializable)
Item theCreatedItem; //This is what was created in the activity
Intent data = new Intent();
data.putSerializable(theCreatedItem);
setResult(RESULT_OK, data);
finish();

This should return to the first Activitys onActivityResult()-method with the item, as explained above.

Upvotes: 1

rus1f1kat0R
rus1f1kat0R

Reputation: 1665

  1. When you are going to start new activity you shouldn't close a current one until you actually need this behaviour. (remove this.finish(); row from your code)
  2. Also you shouldn't close an active activity manually until you actually need it. When the user presses the "back" button on the device Android pops the previous activity from the "back stack". Read once more Activity documentation.
  3. According to your description you have a list of elements. So in order to refresh the list you need to update your dataset and notify the list about it by ListView.notifyDataSetChanged() method call.

Upvotes: 1

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