Android Listview Refresh Single Row

Android ListView Refresh Single Row

One option is to manipulate the ListView directly. First check if the index of the updated row is between getFirstVisiblePosition() and getLastVisiblePosition(), these two give you the first and last positions in the adapter that are visible on the screen. Then you can get the row View with getChildAt(int index) and change it.

Android: Is it possible to refresh just one item in a listview?

You can, but it's a bit convoluted. You would have to get the index of the first visible item in the list and then use that do decide how how far down in the list of visual items the item is that needs updated, then grab its view and update it there.

It's much easier to just call notifyDatasetChanged().

Redraw a single row in a listview

As Romain Guy explained a while back during the Google I/O session, the most efficient way to only update one view in a list view is something like the following (this one update the whole View data):

ListView list = getListView();
int start = list.getFirstVisiblePosition();
for(int i=start, j=list.getLastVisiblePosition();i<=j;i++)
    if(target==list.getItemAtPosition(i)){
        View view = list.getChildAt(i-start);
        list.getAdapter().getView(i, view, list);
        break;
    }

Assuming target is one item of the adapter.

This code retrieve the ListView, then browse the currently shown views, compare the target item you are looking for with each displayed view items, and if your target is among those, get the enclosing view and execute the adapter getView() on that view to refresh the display.

As a side note invalidate() doesn't work like some people expect and will not refresh the view like getView() does, notifyDataSetChanged() will rebuild the whole list and end up calling getview() for every displayed items and invalidateViews() will also affect a bunch.

One last thing, one can also get extra performance if he only needs to change a child of a row view and not the whole row like getView does. In that case, the following code can replace list.getAdapter().getView(i, view, list); (example to change a TextView text):

((TextView)view.findViewById(R.id.myid)).setText("some new text");

In code we trust.

How can I update a single row in a ListView?

I found the answer, thanks to your information Michelle.
You can indeed get the right view using View#getChildAt(int index). The catch is that it starts counting from the first visible item. In fact, you can only get the visible items. You solve this with ListView#getFirstVisiblePosition().

Example:

private void updateView(int index){
    View v = yourListView.getChildAt(index - 
        yourListView.getFirstVisiblePosition());

    if(v == null)
       return;

    TextView someText = (TextView) v.findViewById(R.id.sometextview);
    someText.setText("Hi! I updated you manually!");
}

Updating a single row in Android ListView every millisecond from ArrayAdapter

you should use RecyclerView it is a A flexible view for providing a limited elements into a large data set. so you can use it to control how many items should Be loaded on particular conditions. you can read about the RecyclerView here

ListView Updating a single row

You cannot call the getView() method of the adapter yourself. The adapter's getView() method is is only called, when

• The listview is create
• when the user scrolls the list view

• when notifysetdatachanged() is called.
  
  
  All these are done by the OS. GetView() is called for all the rows in the listview. It is not called for just a single row. So, if you want to change the rows, you have to provide the data again in a String[], ArrayList<> etc
  
  If you want different text to appear for for a single row, onClick() of a button - you can do this

  public class listAdapter extends BaseAdapter{

  public Activity activity;
  public ArrayList<String> text;
  
  public listAdapter(Activity activity){
  
      this.activity = activity;
  }
  
  public void setText(ArrayList<String> text){
      this.text = text;
  }
  
  public int getCount() {
      return 5;
  }
  
  public Object getItem(int position) {
  
      return null;
  }
  
  public long getItemId(int position) {
      // TODO Auto-generated method stub
      return 0;
  }
  
  public View getView(int position, View convertView, ViewGroup parent) {
      LayoutInflater inflater = activity.getLayoutInflater();
      LinearLayout rowView = (LinearLayout) inflater.inflate(R.layout.row_layout, null);
      TextView textView = (TextView) rowView.findViewById(R.id.row_text);
      textView.setText(text[position]);
      return rowView;
  }
  

  }
  
  
  And in your Activity :

  list1 = (ListView) findViewById(R.id.my_list);
  adapter = new listAdapter(this);
  String[] entries={"Normal Text","Normal Text","Normal Text","Normal text","Normal text"};
  ArrayList<String> text=Arrays.asList(entries);
  adapter.setText(text);
  list1.setAdapter(adapter);
  
  Button button1 = (Button) findViewById(R.id.my_button);
  button1.setOnClickListener(new OnClickListener() {
  
      public void onClick(View v) {
         text.set(3,"Different Text");
          adapter.setText(text);
          list1.setAdapter(adapter);
  
      }
  });
  

  
  

  There is another way of doing it also as @Andy suggested in one of the comments :

  listViewPeople.setOnItemClickListener(new ListView.OnItemClickListener() {
          @Override
      public void onItemClick(AdapterView<?> a, View v, int position, long l) {
               //IF YOU WANT TO CHANGE THE CONTENT OF THE ROW CLICKED
         if(position == someNumber) {
                 text.set(position,"different Text");
                 list1.setAdapter(text);
         }
      }
  });
  

Sorry for the bold text. For some reason the CTRL+K is not working for the above code.

update a single row in a ListView?

For updating a single list item you have to get the view at the specified position, and then update the view.

You can get list_item using the following method,

public View getViewByPosition(int position) {
        final int firstListItemPosition = filesListview.getFirstVisiblePosition();
        final int lastListItemPosition = firstListItemPosition + filesListview.getChildCount() - 1;
        if (position < firstListItemPosition || position > lastListItemPosition) {
            // return filesListview.getAdapter().getView(position, filesListview.getChildAt(position), filesListview);
            return null;
        } else {
            final int childIndex = position - firstListItemPosition;
            return filesListview.getChildAt(childIndex);
        }
    }

The above the method will return the view if the View at the given position is visible in the listview otherwise it will return null. For example if the list view contains 20 elements and currently listview is showing 0-6 elements then above method will return the views for 0-6 and others will return null.

       View viewByPosition = getViewByPosition(position;
        // If the retrived view is not null then udpate the view otherwise ignore.
        if (viewByPosition != null) {
           //Update the view
        }

Updating ListView Button in single row without notifyDatasetChanged() in android

You need to call your adapter again when you want to refresh , then it will work

for example,

 private DataAdapter dataAdapter;
        _dataAdapter = new DataAdapter(Activity.this);                 

    if (_dataAdapter != null) {
        DayList.setAdapter(_dataAdapter);
    }

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