Question about the parameter “Context” in ArrayAdapter constructor

First, Here is my code

class MergedView (context : Context,attributeSet: AttributeSet?) : LinearLayout(context,attributeSet) {



var myCalendar : HorizontalCalendar? = null

var scheduleList : ListView?= null



init {



    val infService = Context.LAYOUT_INFLATER_SERVICE

    val li = context.getSystemService(infService) as LayoutInflater

    val v = li.inflate(R.layout.calendar_sequence, this, false)





    addView(v)



    val startDate = Calendar.getInstance()

    startDate.add(Calendar.MONTH, -5)





    val endDate = Calendar.getInstance()

    endDate.add(Calendar.MONTH, 5)



    myCalendar = HorizontalCalendar.Builder(this, R.id.calendarView)

        .range(startDate, endDate)

        .datesNumberOnScreen(5)

        .build()



    myCalendar?.setCalendarListener(object : HorizontalCalendarListener() {

        override fun onDateSelected(date: Calendar, position: Int) {



        }

    })



    val texts = arrayOf("None", "None","None")



    val adapter = 

       ArrayAdapter(context,android.R.layout.simple_list_item_1,texts)



    scheduleList = findViewById(R.id.testList)



    scheduleList?.setAdapter(adapter)



}

}

I am making custom view called merged View which has ListView and HorizontalCalendarView(another custom view)

So, on strictly saying, according to android development document, one of the constructors of ArrayAdapter is

"ArrayAdapter(Context context, int resource, int textViewResourceId, T
objects)". Only one thing I can't understand is Context parameter. According to my understanding, context parameter is a context(Activity) which adapter view is attached. but, then, if adapter View is attatched on custom View (in my case Merged View), then we can say, context is not a thing that adapter view is attached. So I think passing a context to ArrayAdapter constructor is not right(I think passing a custom view sounds more logical).

So here is my question
1. what is the thing I am misunderstanding??
2. what is the correct notion??

asked Nov 25 '18 at 8:40

백근우

The Context is not necessarily what the AdapterView is "attached" to. In the ArrayAdapter, it's just used for access to resources; e.g., an appropriate LayoutInflater.

– Mike M.
Nov 25 '18 at 8:45

So, in my case, context is not the thing ListView is attached to, instead Merged View is the thing ListView is attached to??

– 백근우
Nov 25 '18 at 8:52

In terms of the View hierarchy, yes, your ListView is attached to your MergedView (though there may be other ViewGroups in between). The Context is just something ArrayAdapter needs so it knows how to inflate and style its own item Views internally.

– Mike M.
Nov 25 '18 at 8:56

so... um.. the parameter context must be the activity that view(ListVIew's itemview) is appeared??

– 백근우
Nov 25 '18 at 9:11

It doesn't have to be the Activity, and it may very well not be, depending on how your MergedView is instantiated. It might be a wrapper around your Activity, or some other Context. Whenever you instantiate an ArrayAdapter inside an Activity, though, you just pass the Activity, because it is a Context that has all of the styling information it needs to make the item Views look like your other Views.

– Mike M.
Nov 25 '18 at 9:19

|
show 2 more comments

First, Here is my code

class MergedView (context : Context,attributeSet: AttributeSet?) : LinearLayout(context,attributeSet) {



var myCalendar : HorizontalCalendar? = null

var scheduleList : ListView?= null



init {



    val infService = Context.LAYOUT_INFLATER_SERVICE

    val li = context.getSystemService(infService) as LayoutInflater

    val v = li.inflate(R.layout.calendar_sequence, this, false)





    addView(v)



    val startDate = Calendar.getInstance()

    startDate.add(Calendar.MONTH, -5)





    val endDate = Calendar.getInstance()

    endDate.add(Calendar.MONTH, 5)



    myCalendar = HorizontalCalendar.Builder(this, R.id.calendarView)

        .range(startDate, endDate)

        .datesNumberOnScreen(5)

        .build()



    myCalendar?.setCalendarListener(object : HorizontalCalendarListener() {

        override fun onDateSelected(date: Calendar, position: Int) {



        }

    })



    val texts = arrayOf("None", "None","None")



    val adapter = 

       ArrayAdapter(context,android.R.layout.simple_list_item_1,texts)



    scheduleList = findViewById(R.id.testList)



    scheduleList?.setAdapter(adapter)



}

}

I am making custom view called merged View which has ListView and HorizontalCalendarView(another custom view)

So here is my question
1. what is the thing I am misunderstanding??
2. what is the correct notion??

asked Nov 25 '18 at 8:40

백근우

The Context is not necessarily what the AdapterView is "attached" to. In the ArrayAdapter, it's just used for access to resources; e.g., an appropriate LayoutInflater.

– Mike M.
Nov 25 '18 at 8:45

So, in my case, context is not the thing ListView is attached to, instead Merged View is the thing ListView is attached to??

– 백근우
Nov 25 '18 at 8:52

In terms of the View hierarchy, yes, your ListView is attached to your MergedView (though there may be other ViewGroups in between). The Context is just something ArrayAdapter needs so it knows how to inflate and style its own item Views internally.

– Mike M.
Nov 25 '18 at 8:56

so... um.. the parameter context must be the activity that view(ListVIew's itemview) is appeared??

– 백근우
Nov 25 '18 at 9:11

It doesn't have to be the Activity, and it may very well not be, depending on how your MergedView is instantiated. It might be a wrapper around your Activity, or some other Context. Whenever you instantiate an ArrayAdapter inside an Activity, though, you just pass the Activity, because it is a Context that has all of the styling information it needs to make the item Views look like your other Views.

– Mike M.
Nov 25 '18 at 9:19

|
show 2 more comments

First, Here is my code

class MergedView (context : Context,attributeSet: AttributeSet?) : LinearLayout(context,attributeSet) {



var myCalendar : HorizontalCalendar? = null

var scheduleList : ListView?= null



init {



    val infService = Context.LAYOUT_INFLATER_SERVICE

    val li = context.getSystemService(infService) as LayoutInflater

    val v = li.inflate(R.layout.calendar_sequence, this, false)





    addView(v)



    val startDate = Calendar.getInstance()

    startDate.add(Calendar.MONTH, -5)





    val endDate = Calendar.getInstance()

    endDate.add(Calendar.MONTH, 5)



    myCalendar = HorizontalCalendar.Builder(this, R.id.calendarView)

        .range(startDate, endDate)

        .datesNumberOnScreen(5)

        .build()



    myCalendar?.setCalendarListener(object : HorizontalCalendarListener() {

        override fun onDateSelected(date: Calendar, position: Int) {



        }

    })



    val texts = arrayOf("None", "None","None")



    val adapter = 

       ArrayAdapter(context,android.R.layout.simple_list_item_1,texts)



    scheduleList = findViewById(R.id.testList)



    scheduleList?.setAdapter(adapter)



}

}

I am making custom view called merged View which has ListView and HorizontalCalendarView(another custom view)

So here is my question
1. what is the thing I am misunderstanding??
2. what is the correct notion??

asked Nov 25 '18 at 8:40

백근우

First, Here is my code

class MergedView (context : Context,attributeSet: AttributeSet?) : LinearLayout(context,attributeSet) {



var myCalendar : HorizontalCalendar? = null

var scheduleList : ListView?= null



init {



    val infService = Context.LAYOUT_INFLATER_SERVICE

    val li = context.getSystemService(infService) as LayoutInflater

    val v = li.inflate(R.layout.calendar_sequence, this, false)





    addView(v)



    val startDate = Calendar.getInstance()

    startDate.add(Calendar.MONTH, -5)





    val endDate = Calendar.getInstance()

    endDate.add(Calendar.MONTH, 5)



    myCalendar = HorizontalCalendar.Builder(this, R.id.calendarView)

        .range(startDate, endDate)

        .datesNumberOnScreen(5)

        .build()



    myCalendar?.setCalendarListener(object : HorizontalCalendarListener() {

        override fun onDateSelected(date: Calendar, position: Int) {



        }

    })



    val texts = arrayOf("None", "None","None")



    val adapter = 

       ArrayAdapter(context,android.R.layout.simple_list_item_1,texts)



    scheduleList = findViewById(R.id.testList)



    scheduleList?.setAdapter(adapter)



}

}

I am making custom view called merged View which has ListView and HorizontalCalendarView(another custom view)

So here is my question
1. what is the thing I am misunderstanding??
2. what is the correct notion??

android android-arrayadapter

asked Nov 25 '18 at 8:40

백근우

asked Nov 25 '18 at 8:40

백근우

asked Nov 25 '18 at 8:40

백근우

asked Nov 25 '18 at 8:40

백근우

asked Nov 25 '18 at 8:40

백근우

The Context is not necessarily what the AdapterView is "attached" to. In the ArrayAdapter, it's just used for access to resources; e.g., an appropriate LayoutInflater.

– Mike M.
Nov 25 '18 at 8:45

So, in my case, context is not the thing ListView is attached to, instead Merged View is the thing ListView is attached to??

– 백근우
Nov 25 '18 at 8:52

In terms of the View hierarchy, yes, your ListView is attached to your MergedView (though there may be other ViewGroups in between). The Context is just something ArrayAdapter needs so it knows how to inflate and style its own item Views internally.

– Mike M.
Nov 25 '18 at 8:56

so... um.. the parameter context must be the activity that view(ListVIew's itemview) is appeared??

– 백근우
Nov 25 '18 at 9:11

It doesn't have to be the Activity, and it may very well not be, depending on how your MergedView is instantiated. It might be a wrapper around your Activity, or some other Context. Whenever you instantiate an ArrayAdapter inside an Activity, though, you just pass the Activity, because it is a Context that has all of the styling information it needs to make the item Views look like your other Views.

– Mike M.
Nov 25 '18 at 9:19

|
show 2 more comments

The Context is not necessarily what the AdapterView is "attached" to. In the ArrayAdapter, it's just used for access to resources; e.g., an appropriate LayoutInflater.

– Mike M.
Nov 25 '18 at 8:45

So, in my case, context is not the thing ListView is attached to, instead Merged View is the thing ListView is attached to??

– 백근우
Nov 25 '18 at 8:52

In terms of the View hierarchy, yes, your ListView is attached to your MergedView (though there may be other ViewGroups in between). The Context is just something ArrayAdapter needs so it knows how to inflate and style its own item Views internally.

– Mike M.
Nov 25 '18 at 8:56

so... um.. the parameter context must be the activity that view(ListVIew's itemview) is appeared??

– 백근우
Nov 25 '18 at 9:11

It doesn't have to be the Activity, and it may very well not be, depending on how your MergedView is instantiated. It might be a wrapper around your Activity, or some other Context. Whenever you instantiate an ArrayAdapter inside an Activity, though, you just pass the Activity, because it is a Context that has all of the styling information it needs to make the item Views look like your other Views.

– Mike M.
Nov 25 '18 at 9:19

The Context is not necessarily what the AdapterView is "attached" to. In the ArrayAdapter, it's just used for access to resources; e.g., an appropriate LayoutInflater.

– Mike M.
Nov 25 '18 at 8:45

So, in my case, context is not the thing ListView is attached to, instead Merged View is the thing ListView is attached to??

– 백근우
Nov 25 '18 at 8:52

In terms of the View hierarchy, yes, your ListView is attached to your MergedView (though there may be other ViewGroups in between). The Context is just something ArrayAdapter needs so it knows how to inflate and style its own item Views internally.

– Mike M.
Nov 25 '18 at 8:56

so... um.. the parameter context must be the activity that view(ListVIew's itemview) is appeared??

– 백근우
Nov 25 '18 at 9:11

It doesn't have to be the Activity, and it may very well not be, depending on how your MergedView is instantiated. It might be a wrapper around your Activity, or some other Context. Whenever you instantiate an ArrayAdapter inside an Activity, though, you just pass the Activity, because it is a Context that has all of the styling information it needs to make the item Views look like your other Views.

– Mike M.
Nov 25 '18 at 9:19

|
show 2 more comments

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