ArrayAdapter in android to create simple listview

Question

I tried to create an Activity in Android  This Activity only contains a ListView nothing else   As I know to fill the listview we need to use an ArrayAdapter   So to understand the ArrayAdapter I have read the following link   http   developer android com reference android widget ArrayAdapter html  But still I am unable to understand it clearly   One of the biggest doubt is why the constructor needs a TextView resource id while my activity is not having any TextViews what I should have to give it   I am not saying that this is the only constructor  just that I m unable to understand the logic behind it   In order to create a simple listview I also referred to the following link   Simple ListView using ArrayAdapter example   But again my main doubt is why it does it need a TextView resource id   If anybody can explain it with an example it will be very helpful   EDIT   ArrayAdapter lt String gt  adapter   new ArrayAdapter lt String gt  this            android R layout simple list item 1  android R id text1  values

User · Answer

public ArrayAdapter  Context context  int resource  int textViewResourceId  T   objects    I am also new to Android   so i might be wrong  But as per my understanding while using this for listview creation 2nd argument is the layout of list items  A layout consists of many views  image view text view etc   With 3rd argument you are specifying in which view or textview you want the text to be displayed

User · Answer

You don t need to use id for textview  You can learn more from android arrayadapter  The below code initializes the arrayadapter   ArrayAdapter arrayAdapter   new ArrayAdapter this  R layout single item  eatables

User · Answer

ArrayAdapter uses a TextView to display each item within it  Behind the scenes  it uses the toString   method of each object that it holds and displays this within the TextView  ArrayAdapter has a number of constructors that can be used and the one that you have used in your example is   ArrayAdapter Context context  int resource  int textViewResourceId  T   objects    By default  ArrayAdapter uses the default TextView to display each item  But if you want  you could create your own TextView and implement any complex design you d like by extending the TextView class  This would then have to go into the layout for your use  You could reference this in the textViewResourceId field to bind the objects to this view instead of the default   For your use  I would suggest that you use the constructor   ArrayAdapter Context context  int resource  T   objects      In your case  this would be    ArrayAdapter lt String gt  this  android R layout simple list item 1  values    and it should be fine  This will bind each string to the default TextView display - plain and simple white background    So to answer your question  you do not have to use the textViewResourceId

User · Answer

public ArrayAdapter  Context context  int resource  int textViewResourceId  T   objects    Here  resource means the  id  of the Layout you are using while instantiating the view   Now  this layout has many child views with their own ids  So  textViewResourceId tells which child view we need to populate with the data

User · Answer

But again main doubt why TextView resource id it needs    Look at the constructor and the params   public ArrayAdapter  Context context  int resource  int textViewResourceId  T   objects       Added in API level 1 Constructor      Parameters       context The current context        resource    The resource ID for a   layout file containing a layout to use when instantiating views       textViewResourceId  The id of the TextView within the layout resource   to be populated objects   The objects to represent in the ListView    android R id text1 refers to the id of text in android resource  So you need not have the one in your activity   Here s the full list  http   developer android com reference android R id html  ArrayAdapter lt String gt  adapter   new ArrayAdapter lt String gt  this          android R layout simple list item 1  android R id text1  values     this refers to activity context  android R layout simple list item 1 simple list item 1 is the layout in android R layout   android R id text1 refers to the android resource id   values is a string array from the link you provided  http   developer android com reference android R layout html

User · Answer

For your question answer is android R id text1 is int  The id of the TextView within the layout resource to be populated   ArrayAdapter has so many constructors with different number of arguments  I m mention some of them  ArrayAdapter Context context  int resource  ArrayAdapter Context context  int resource  int textViewResourceId  ArrayAdapter Context context  int resource  T   objects  ArrayAdapter Context context  int resource  int textViewResourceId  T   objects  ArrayAdapter Context context  int resource  List lt T gt  objects  ArrayAdapter Context context  int resource  int textViewResourceId  List lt T gt  objects    Now you can understand each and every constructor is different and they used different list of arguments    And simple answer is you can use ArrayAdapter with text view inside a target xml file or without  It is doesn t matter  And you not need specify text view id you can use it without  But you may need to go with some advance option with your simple list view you must go with a text view    Here sample example   ArrayAdapter adapter   new ArrayAdapter lt String gt  this R layout ListView StringArray   ListView listView    ListView  findViewById R id listview   listView setAdapter adapter     This is also a valid code you can use with much more clear

User · Answer

The TextView resource id it needs is for a TextView layout file  so it won t be in the same activity    You can create it by going to File   New   XML   XML Layout File  and enter the widget type  which is  TextView  in the root tag field   Source  https   www kompulsa com the-simplest-way-to-implement-an-android-listview

User · Answer

If you have more than one view in the layout file android R layout simple list item 1 then you ll have to pass the third argument android R id text1 to specify the view that should be filled with the array elements  values   But if you have just one view in your layout file  there is no need to specify the third argument

[android] ArrayAdapter in android to create simple listview

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