子类SimpleCursorAdapter包括convertView内存保护 [英] Subclassing SimpleCursorAdapter to include convertView for memory conservation

问题描述

我已经冲刷通过量的例子和教程，但我似乎无法让我的头，围绕如何处理回收中的子类SimpleCursorAdapter。我知道，对于普通ArrayAdapters您可以检查convertView为空，如果从XML空，如果不为空充气，回收，但我有一个小麻烦可视化如何，随着往返于SimpleCursorAdapter子类中的数组工作。我想这出由Commonsware中的忙codeRS指南Android的发展，但没有成功。如果有人知道的任何提示，实例，或教程，我将不胜感激，看到他们。

I've been scouring throug the examples and tutorials but I can't seem to get my head around how to handle recycling within a subclassed SimpleCursorAdapter. I know that for regular ArrayAdapters you can check convertView for null and inflate if null from the xml and if not null, recycle, but I'm having a little trouble visualizing how that works with the from and to arrays within the SimpleCursorAdapter subclass. I tried to figure this out from the The Busy Coders Guide to Android Development by Commonsware but was unsuccessful. If anyone knows of any tips, examples, or tutorials, I would be grateful to see them.

推荐答案

我无法找到子类化SimpleCursorAdapter使用convertView循环methodolgy所以我最终CursorAdapter的子类，而不是什么好的例子。这实际上相当奏效了我的实现，并在内存使用量的急剧下降极快。回收的意见真正起作用的，我高度推荐它！

I was unable to find any good examples for Subclassing the SimpleCursorAdapter to use the convertView recycle methodolgy so I ended up subclassing CursorAdapter instead. This actually worked quite well for my implementation and is blazing fast with a dramatic decrease in memory usage. Recycling views really works and I recommend it highly!

下面是我实现的例子：

 private static class MyNiftyAdapter extends CursorAdapter
    {
        private LayoutInflater mInflater;
        private Cursor cur;

        public MyNiftyAdapter(Context context, Cursor c) {
            super(context,c);       
            this.mInflater = LayoutInflater.from(context);
            this.cur = c;
        }
        public MyNiftyAdapter(Context context, Cursor c, boolean autoRequery)
        {
            super(context, c, autoRequery);
            this.mInflater = LayoutInflater.from(context);
            this.cur = c;
        }
        @Override
        public View getView(int position, View convertView, ViewGroup parent)
        {
            ViewHolder viewHolder;
            if(convertView == null)
            {
                convertView = this.mInflater.inflate(R.layout.chamber_item, null);
                viewHolder = new ViewHolder();
                viewHolder.name = (TextView)convertView.findViewById(R.id.Name);
                viewHolder.city = (TextView)convertView.findViewById(R.id.city);
                viewHolder.state = (TextView)convertView.findViewById(R.id.state);
                viewHolder.country = (TextView)convertView.findViewById(R.id.country);
                convertView.setTag(viewHolder);
            }else
            {
                viewHolder = (ViewHolder)convertView.getTag();
            }
            this.cur.moveToPosition(position);

            viewHolder.name.setText(this.cur.getString(this.cur.getColumnIndex(MyDBHelper.NAME)));          
            viewHolder.city.setText(this.cur.getString(this.cur.getColumnIndex(MyDBHelper.CITY)));
            viewHolder.state.setText(this.cur.getString(this.cur.getColumnIndex(MyDBHelper.STATE)));
            viewHolder.country.setText(this.cur.getString(this.cur.getColumnIndex(MyDBHelper.COUNTRY)));            

            return convertView;
        }
        /* (non-Javadoc)
         * @see android.widget.CursorAdapter#bindView(android.view.View, android.content.Context, android.database.Cursor)
         */
        @Override
        public void bindView(View view, Context context, Cursor cursor) {
            // Dont need to do anything here

        }
        /* (non-Javadoc)
         * @see android.widget.CursorAdapter#newView(android.content.Context, android.database.Cursor, android.view.ViewGroup)
         */
        @Override
        public View newView(Context context, Cursor cursor, ViewGroup parent) {
            // Dont need to do anything here either
            return null;
        }

        static class ViewHolder
        {
            TextView name;
            TextView city;
            TextView state;
            TextView country;
        }
    }

在我的名单上的每一行现在显示的名称，城市，州和国家完全按照我想要的。希望这有助于。

Each row in my list now displays name, city, state, and country exactly as I wanted. Hope this helps.

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