Get value in activity from getView of BaseAdapter

Question

I have a listview and for that i am using a BaseAdapter. I want the value of listitem in that Activity . Below is my code

MainActivity.java

ArrayList<String> dkulist = new ArrayList<>();
CustomAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_layout);
    userList = (ListView) findViewById(R.id.userList);
    userList.setAdapter(adapter);
}

CustomAdapter.java

public class CustomAdapter extends BaseAdapter {
    @Override
    public View getView(int position, View convertView,final ViewGroup  parent) {
        if (convertView == null) {
          LayoutInflater inflater = LayoutInflater.from(parent.getContext());
          convertView = inflater.inflate(R.layout.listitem, parent, false);
    }        

    TextView Name = (TextView) convertView.findViewById(R.id.name);

    Name.setText("Dummy name");
    final boolean click_flag = false;
    convertView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
          if(click_flag) {
             view.setBackgroundColor(Color.BLUE); // this is also not working
             // How to get this name value in my MainActivity.java
          } else {
             view.setBackgroundColor(Color.TRANSPARENT);
          }
        }
}

Thank in Adv

click_flag is always going to be false... Where are you changing the flag? — Samuel Robert, Aug 14 '17 at 05:34

score 2 · Answer 1 · edited Aug 14 '17 at 05:53

2

Use an Interface to pass the value to Activity

public interface OnItemClickListener {
    void onItemClick (Object value);
}

Implement the above listener in the Activity and pass an instance of this to the adapter

private final OnItemClickListener mListener;

convertView.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
         view.setBackgroundColor(Color.BLUE); // this will work now
         // This is how to get this name value in my MainActivity.java
         mListener.onItemClick(value);
    }

edited Aug 14 '17 at 05:53

Naveen Tamrakar

3,349
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28

answered Aug 14 '17 at 05:26

Samuel Robert

10,106
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60

Please explain i did not understand – manjari Aug 14 '17 at 05:30
So you can use an interface to communicate between activity and adapter. Writing the complete code below – Harsh Aug 14 '17 at 05:32

score 0 · Answer 2 · answered Aug 14 '17 at 05:33

0

You need to initialize instance for the Adapter and set to the userlist instead of just passing the unassigned adapter variable.

answered Aug 14 '17 at 05:33

Arun Prasad

360
3
18

Harsh · Answer 3 · 2017-08-14T15:47:05.153

Activity code:

public class MainActivity implements CustomAdapter. OnItemClickListener

ArrayList<String> dkulist = new ArrayList<>();
CustomAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_layout);
    userList = (ListView) findViewById(R.id.userList);
    userList.setAdapter(adapter);
}

@override
public void onItemClick (Object value){
// do your stuff here
}
}

Adapter code:

public class CustomAdapter extends BaseAdapter {

private final OnItemClickListener mListener;

   public CustomAdapter(Context context){
    // this will register the listener with MainActivity.java
    mListener = (OnItemClickListener) context
   }
    @Override
    public View getView(int position, View convertView,final ViewGroup  parent) {
        if (convertView == null) {
          LayoutInflater inflater = LayoutInflater.from(parent.getContext());
          convertView = inflater.inflate(R.layout.listitem, parent, false);
    }        

    TextView Name = (TextView) convertView.findViewById(R.id.name);

    Name.setText("Dummy name");
    final boolean click_flag = false;
    convertView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
          if(click_flag) {
             view.setBackgroundColor(Color.BLUE); // this is also not working
             // How to get this name value in my MainActivity.java
             // Add below code to delegate the value to activity
             mListener.onItemClick(value);
          } else {
             view.setBackgroundColor(Color.TRANSPARENT);
          }
        }

public interface OnItemClickListener {
    void onItemClick (Object value);
}
}

java.lang.ClassCastException in this line mListener = (AdapterView.OnItemClickListener) context; — manjari, Aug 14 '17 at 05:57

score 0 · Answer 4 · answered Aug 14 '17 at 05:51

Try this

In your MainAcitivity.java,

userList.setOnItemClickListener(new ListItemClickListener());

private class ListItemClickListenerimplements ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position,
                                long id) {
            String text = ((TextView) view.findViewById(R.id.name)).getText().toString();
        }

    }

Get value in activity from getView of BaseAdapter

4 Answers4