在ListView中为列表项设置动画

Question

我尝试在ListView中为新项目制作动画.我有稳定的id-s,所以我确切知道要动画的元素.问题来自ListView的循环机制.当我知道我有一个最近插入的元素时,我在视图上调用startAnimation.但随后,视图得到了回收,充满了不同的数据.它会在UI上为错误的行设置动画.在某些时候,视图持有正确的数据,但随后被回收.我通过logcat证实了这一点.有什么方法可以解决这个问题吗？

编辑:

public ExpensCursorAdapter(Context context, Cursor c, boolean autoRequery,
        CopyOnWriteArraySet<String> fadeAnimateTags) {
    super(context, c, autoRequery);
    this.mFadeAnimTags = fadeAnimateTags;
}

@Override
public boolean hasStableIds() {
    return true;
}

@Override
public void bindView(View view, Context context, Cursor cursor) {
    setup(view, context, cursor);
}

private void setup(View view, Context context, Cursor cursor) {
    final String id = cursor.getString(4);
    if (LOCAL_LOGV) Log.v(TAG, String.format("Create item for %s. Received view: %s", id, view.toString()));
    view.setTag(id);
    final TextView dateText = (TextView) view.findViewById(R.id.date);
    final TextView timeText = (TextView) view.findViewById(R.id.time);
    final TextView title = (TextView) view.findViewById(R.id.title);
    final TextView amount = (TextView) view.findViewById(R.id.amount);
    final Date date = new Date(cursor.getLong(0));
    title.setText(cursor.getString(1));
    dateText.setText(dFormat.format(date));
    timeText.setText(tFormat.format(date));
    amount.setText(String.format("%d Ft", cursor.getInt(2)));
    if (cursor.getInt(3) == 1) {
        timeText.setTextColor(Color.LTGRAY);
        title.setTextColor(Color.LTGRAY);
        dateText.setTextColor(Color.LTGRAY);
        amount.setTextColor(Color.LTGRAY);
    } else {
        timeText.setTextColor(Color.BLACK);
        title.setTextColor(Color.BLACK);
        dateText.setTextColor(Color.BLACK);
        amount.setTextColor(Color.BLACK);
    }
    if (mFadeAnimTags.contains(id)) {
     view.setAnimation(AnimationUtils.loadAnimation(context, R.anim.fade));
     mFadeAnimTags.remove(id);
    }

}

@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
    final LayoutInflater inflater = LayoutInflater.from(context);
    View view = inflater.inflate(R.layout.expense_list_item, parent, false);
    setup(view, context, cursor);
    return view;
}

Answer 1

如果你在这里使用getView()简单代码, (不需要自定义库)

private int lastPosition = -1;

@Override
public View getView(int position, View convertView, ViewGroup parent) {
//Load your view, populate it, etc...
View view = ...;

Animation animation = AnimationUtils.loadAnimation(getContext(), (position > lastPosition) ? R.anim.up_from_bottom : R.anim.down_from_top);
view.startAnimation(animation);
lastPosition = position;

return view;
}

up_from_bottom.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
 android:shareInterpolator="@android:anim/decelerate_interpolator">
<translate
    android:fromXDelta="0%" android:toXDelta="0%"
    android:fromYDelta="100%" android:toYDelta="0%"
    android:duration="400" />
</set>

down_from_bottom.xml

 <?xml version="1.0" encoding="utf-8"?>
 <set xmlns:android="http://schemas.android.com/apk/res/android"
 android:shareInterpolator="@android:anim/decelerate_interpolator">
<translate
    android:fromXDelta="0%" android:toXDelta="0%"
    android:fromYDelta="-100%" android:toYDelta="0%"
    android:duration="400" />
 </set>

本网站的参考资料:http://kylewbanks.com/blog/Implementing-Google-Plus-Style-ListView-Animations-on-Android

Answer 2

在自定义适配器的getView方法中为每个添加的元素设置动画.

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;
}

从而实现动画.

Answer 3

我有类似的问题。我不确定这是否是正确的方法，但您可以尝试在开始新视图之前清除视图上的动画，以取消回收视图中的任何剩余动画。这对我有帮助。

if(flag == false) {
    v.clearAnimation();
    Animation animation = AnimationUtils.loadAnimation(getActivity(), R.anim.slide_top_to_bottom);
    v.startAnimation(animation);
}