ListView Custom Adapter applies actions on wrong Items OnScroll

Question

I have a normal setup for a ListView and Custom ArrayAdapter. and i'm stipulating if something equals to something then change color of that item.

at the first load, the condition works for correct items that i change thier color (if condition).

The issue begins to appear when i scroll the ListView up and down continually, the color changing for wrong items randomly and reverts back to original as i keep scrolling. even the correct ones randomly changing. till i get all the items on the list set with that color!

Let's say only one item has (true) value and the rest is (false) then i condition if true, change color. but when i scroll (not at first load) other items gets that color even they're false.

but the data i set with disabledTextView.setText("correct item"); does not change it keeps as it's correct, which is good.

MyCustomAdapter.java

public class MyCustomAdapter extends ArrayAdapter<HashMap<String, String>> {

    private Context context;
    private ArrayList<HashMap<String, String>> myArray;

    public MyCustomAdapter(Context context, ArrayList<HashMap<String, String>> theArray) {
        super(context, R.layout.my_single_list_item, theArray);

        this.context = context;
        this.myArray = theArray;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.my_single_list_item, parent, false);
        }

        HashMap<String, String> arrayItem = myArray.get(position);

        boolean disabled = Boolean.valueOf(arrayItem.get("disabled"));

        TextView disabledTextView = convertView.findViewById(R.id.disabledTextView);

        disabledTextView.setText(String.valueOf(disabled));

        if(disabled) {
            disabledTextView.setTextColor(getContext().getResources().getColor(R.color.design_default_color_error));
        }

        return convertView;
    }

}

my_single_list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/disabledTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="12sp"
        android:textColor="@android:color/black" />

</LinearLayout>

What causes this problem?

Update (Solved) : but more information still needed!

after getting rid of using convertView and replaced it with customView with new LayoutInflater :

public View getView(int position, View convertView, ViewGroup parent) {

    View customView = LayoutInflater.from(getContext()).inflate(R.layout.my_single_list_item, parent, false);
}

TextView hotspotUserDisabled = customView.findViewById(R.id.hotspotUserDisabled);

//.. etc

The problem is solved. i'm still too confused with that, should i only use new View inflate only if View convertView is null?

because the IDE shows a hint :

When implementing a view Adapter, you should avoid unconditionally inflating a new layout; if an available item is passed in for reuse, you should try to use that one instead. This helps make for example ListView scrolling much smoother.

What if i need to fix this and still use the View that is passed to keep scrolling smoother?

Thanks!

Answer 1

You need to define else case in getView method

if(disabled) {
    disabledTextView.setTextColor(getContext().
    getResources().getColor(R.color.design_default_color_error));
}else{
    // add code here
}