how to pass an arraylist of books between activities

Question

I have an arraylist of type Book. How can I pass the array list to another activity and read from that list in the other activity? Here's what I have so far.

   txtViewAll.setOnClickListener {
                Intent(context, BookActivity::class.java).apply {
                    putExtra("list", list[layoutPosition].list)
                    context.startActivity(this)
                }
            }

// to read

val bookList = intent.getStringArrayListExtra("list") as ArrayList<Book>
            for (book in bookList) {
                list.add(Book(book.id, book.title, book.image, book.subtitle, null, null, 0, 0));
            }

Here's each Book

data class Book(val id: String, val title: String, var image: String, var subtitle: String, var author: String?, var desc: String?, var uploadDate: Long,  var starCount: Long)

Implement your Book class as Parcelable & use bundle.putParcelableArrayList & in 2nd activity getParcelableArrayList — Gautam, Mar 10 '20 at 04:50

IntelliJ Amiya · Accepted Answer · 2020-03-10T05:11:40.787

1

You can use putParcelableArrayListExtra & getParcelableArrayListExtra .

Set this way

Intent(context, BookActivity::class.java).apply {
putParcelableArrayListExtra("list", list[layoutPosition].list)
context.startActivity(this)

Get this way

val bookList = this.intent.getParcelableArrayListExtra<Parcelable>("list") as ArrayList<Book>

You should use Parcelable

Use @Parcelize annotation on top of your Model / Data class

Example

@Parcelize
data class Book

Parcelable is an Android only interface which is used to serialize
class so its properties can be transferred from one activity to
another.

edited Mar 10 '20 at 05:11

answered Mar 10 '20 at 04:50

IntelliJ Amiya

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putParcelableArrayListExtra("list", list[layoutPosition].list) tells me that the second argument is of the wrong type – Chris Hansen Mar 10 '20 at 04:54
@LouisaScheinost seems like you should pass `list[layoutPosition]` instead of `list[layoutPosition].list` – IntelliJ Amiya Mar 10 '20 at 05:14
I think this is bad solution, so many time i see app crash when list too large. You can create an variable in MainApplication class, it's better or save it in some database. – Hoàng Vũ Anh Mar 10 '20 at 09:09
1

It is something to consider: TransactionTooLargeException. The limitation is different on different versions of Android, but you can probably consider it to be 1MB as a baseline. But for a large amount of variable data I would tend to reopen it from the DB in the new Activity. Having said that, the answer above is really educational in terms of what is being attempted. – Elletlar Mar 10 '20 at 09:37

how to pass an arraylist of books between activities

1 Answers1