Animate newly added items in ListView

问题:

How can I animate newly added items in ListView?

I have a adapter and when I add new items in my list I say adapter.notifyDataSetChanged(); the items are added, everything works perfectly, but my problem is I want newly added element to have some animation.

回答1:

Animate each added element in the getView() method of your Custom Adapter.

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

    View v = convertView;

    if (v == null) {
        LayoutInflater vi = (LayoutInflater) getActivity()
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        v = vi.inflate(R.layout.simple_list_item_1, null);
    }

    ListData o = list.get(position);
    TextView tt = (TextView) v.findViewById(R.id.toptext);

    tt.setText(o.content);

    Log.d("ListTest", "Position : "+position);
    if(flag == false) {
        Animation animation = AnimationUtils
                .loadAnimation(getActivity(), R.anim.slide_top_to_bottom);
        v.startAnimation(animation);
    }
    return v;
}

And thereby achieve the Animation.

回答2:

The official docs about animation in Android say that you can set an animation to trigger whenever the layout is changed, using android:animateLayoutChanges="true".

Taken from: http://developer.android.com/training/animation/layout.html

回答3:

Adding this kind of animations is harder than I first thought of. There are two ways depending of the kind of animation you are trying to achieve.

• Using LayoutAnimationController. There is an example in the API demos.

• Animating each View:

This is quite a hack but the only way I found to add an animation to ListView's children is the following:

You can try notifying the adapter the id of the item you are willing to delete and call adapter.notifyDataSetChanged();. This will generate calls to the adapter's getView() method. Inside it you can do something like:

if ( item.getId() == itemToRemove ) {
 //apply the animation
}

After the animation finished you can recall adapter.notifyDataSetChanged() to put everything in place.