将数据从片段传递到活动不一样

Question

I have fragment in activity. and I want to send data from fragment to activity.

how I get data in Fragment and send to my Activity:

val edit = question!!.id
(activity as QuestionActivity).kirimItem(edit)

in activity :

fun kirimItem(item: String) {
    idItem = item
}

and I call idItem in the button next onClick and show Toast the value from idItem

in the fragment, when I test data, question!!.id = 8 but toast is showing 11. The question is, why passing data from fragment to activity is not same. please guide me:(

Answer 1

There are recommendations for passing data between activities and fragments (in a same activity). These are possible scenarios.

1. (Activity -> Activity)
2. (Activity -> Fragment)
3. (Fragment -> Activity)
4. (Fragment -> Fragment)

For 1., just use just use android.content.Intent . For 2., 3. and 4. scenarios, we can use android.arch.lifecycle.ViewModel to passing data between them. An example for 4. (Fragment -> Fragment) is here ( https://developer.android.com/topic/libraries/architecture/viewmodel ) under topic Share data between fragments .

For that example, it can be applied not only 4. scenario but also to 2. and 3. as well.

Answer 2

I am not sure that what is the rest of our code. This piece of code below works for me.

// Fragment, `btn` is Button and `edt` is EditText
btn.setOnClickListener {
    (activity as MainActivity?)?.callToast(edt.text.toString())
}

// Activity
fun callToast(str: String) {
    Toast.makeText(this, str, LENGTH_SHORT).show()
}