Android ListView、GridView等性能优化

1.采用ViewHolder并避免在getView中执行耗时操作

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.image_list_item,parent, false);
holder = new ViewHolder();
holder.imageView = (ImageView) convertView.findViewById(R.id.image);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
ImageView imageView = holder.imageView;
final String tag = (String)imageView.getTag();
final String uri = getItem(position);
if (!uri.equals(tag)) {
imageView.setImageDrawable(mDefaultBitmapDrawable);
}
if (mIsGridViewIdle && mCanGetBitmapFromNetWork) {
imageView.setTag(uri);
mImageLoader.bindBitmap(uri, imageView, mImageWidth, mImageWidth);
}
return convertView;
}

}

private static class ViewHolder {
    public ImageView imageView;
}

2.根据列表的滑动状态来控制任务的执行频率

监听滑动状态，当滑动停止的时候再去加载图片
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
if (scrollState == OnScrollListener.SCROLL_STATE_IDLE) {
mIsGridViewIdle = true;
mImageAdapter.notifyDataSetChanged();
} else {
mIsGridViewIdle = false;
}
}

3.尝试硬件加速来使ListView滑动更加流畅

android:hardwareAccelerated=”true”