Updating a single row in Android ListView every millisecond from ArrayAdapter

问题

I have a ListView and ArrayAdapter set on it. My ListView single row contains TextView and start Button. When click on button the TextView text will be changed every millisecond. I have defined timer for it but when I change TextView text it doesn't appears on my view. It changes only when I call notifyDataSetChanged. But in this case calling notifyDataSetChanged every millisecond, my ListView is crashed. How can I solve this problem? In addition to I want to say that I implemented ArrayAdapter with ViewHolder pattern and overrided all necessary methods.

回答1:

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

回答2:

As Harshad wrote, you can use RecyclerView and it's the best way.

If for some reason you don't want, you can update specific list view row manually using this line code:

View convertView = listview.getChildAt(rowIndex - listview.getFirstVisiblePosition());

It's much faster than notifyDataChanged...

回答3:

I made up another solution, like RecyclerView method void notifyItemChanged(int position), create CustomBaseAdapter class just like this:

public abstract class CustomBaseAdapter implements ListAdapter, SpinnerAdapter {

    private final CustomDataSetObservable mDataSetObservable = new CustomDataSetObservable();

    public boolean hasStableIds() {
        return false;
    }

    public void registerDataSetObserver(DataSetObserver observer) {
        mDataSetObservable.registerObserver(observer);
    }

    public void unregisterDataSetObserver(DataSetObserver observer) {
        mDataSetObservable.unregisterObserver(observer);
    }

    public void notifyDataSetChanged() {
        mDataSetObservable.notifyChanged();
    }

    public void notifyItemChanged(int position) {
        mDataSetObservable.notifyItemChanged(position);
    }

    public void notifyDataSetInvalidated() {
        mDataSetObservable.notifyInvalidated();
    }

    public boolean areAllItemsEnabled() {
        return true;
    }

    public boolean isEnabled(int position) {
        return true;
    }

    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        return getView(position, convertView, parent);
    }

    public int getItemViewType(int position) {
        return 0;
    }

    public int getViewTypeCount() {
        return 1;
    }

    public boolean isEmpty() {
        return getCount() == 0;
    }
}

Don't forget to create a CustomDataSetObservable class too for mDataSetObservable variable in CustomAdapterClass, like this:

public class CustomDataSetObservable extends Observable<DataSetObserver> {

    public void notifyChanged() {
        synchronized(mObservers) {
            // since onChanged() is implemented by the app, it could do anything, including
            // removing itself from {@link mObservers} - and that could cause problems if
            // an iterator is used on the ArrayList {@link mObservers}.
            // to avoid such problems, just march thru the list in the reverse order.
            for (int i = mObservers.size() - 1; i >= 0; i--) {
                mObservers.get(i).onChanged();
            }
        }
    }

    public void notifyInvalidated() {
        synchronized (mObservers) {
            for (int i = mObservers.size() - 1; i >= 0; i--) {
                mObservers.get(i).onInvalidated();
            }
        }
    }

    public void notifyItemChanged(int position) {
        synchronized(mObservers) {
            // since onChanged() is implemented by the app, it could do anything, including
            // removing itself from {@link mObservers} - and that could cause problems if
            // an iterator is used on the ArrayList {@link mObservers}.
            // to avoid such problems, just march thru the list in the reverse order.
            mObservers.get(position).onChanged();
        }
    }
}

on class CustomBaseAdapter there is a method notifyItemChanged(int position), and you can call that method when you want update a row wherever you want (from button click or anywhere you want call that method). And voila!, your single row will update instantly..

Hope this solution will help you..

来源：https://stackoverflow.com/questions/33196142/updating-a-single-row-in-android-listview-every-millisecond-from-arrayadapter