ListView优化总结

1.适配器优化

1.1ViewHolder类封装

1.ViewHolder类原始类

 class ViewHolder{     TextView name;     TextView age; }

封装类

/** * 封装视图类 * @author nate */public class CommViewHolder{    /**     * 视图容器     */    private SparseArray<View> mViews;    /**     * 位置标识     */    private int mPosition;    /**     * 视图     */    private View mConvertView;    /**     * 私有化构造方法，不让外界进行使用     * @param context     * @param parent     * @param layoutId     * @param position     */    private CommViewHolder(Context context, ViewGroup parent, int layoutId, int position)    {        this.mViews = new SparseArray<View>();        this.mConvertView = LayoutInflater.from(context).inflate(layoutId, parent, false);        this.mPosition = position;        mConvertView.setTag(this);    }    /**     *      * @param context     * @param parent     * @param layoutId     * @param position     * @param convertView     * @return 静态方法获取到viewholder类实例     */    public static CommViewHolder get(Context context, ViewGroup parent, int layoutId, int position, View convertView)    {        if(convertView == null)        {            return new CommViewHolder(context, parent, layoutId, position);        }        else        {            CommViewHolder holder = (CommViewHolder) convertView.getTag();            // 复用视图，但是position要更新            holder.mPosition = position;            return holder;        }    }    /**     *      * @param viewId 控件id     * @return 根据控件id获取到控件     */    @SuppressWarnings("unchecked")    public <T extends View> T getView(int viewId)    {        View view = mViews.get(viewId);        if(view == null)        {            view = mConvertView.findViewById(viewId);            mViews.put(viewId, view);        }        return (T) view;    }    /**     * @return 返回视图类     */    public View getmConvertView()    {        return mConvertView;    }    /**     * @param viewId     * @param content     * @return 设置textview相关     */    public CommViewHolder setTextView(int viewId, String content)    {        TextView tv = getView(viewId);        tv.setText(content);        return this;    }    // TODO 可以根据自己的需要编写更多适用的方法。。。}

2.Adapter类中Viewholder代码对比使用原始holder

 class MyAdapter extends ArrayAdapter<Person>    {        public MyAdapter(Context context, int resource, List<Person> objects)        {            super(context, resource, objects);        }        @Override        public View getView(int position, View convertView, ViewGroup parent)        {            ViewHolder holder = null;            if(convertView == null)            {                holder = new ViewHolder();                convertView = LayoutInflater.from(getContext()).inflate(R.layout.item_layout, null);                holder.name = (TextView) convertView.findViewById(R.id.name);                holder.age = (TextView) convertView.findViewById(R.id.age);                convertView.setTag(holder);            }            else            {                holder = (ViewHolder) convertView.getTag();            }            Person person = getItem(position);            holder.name.setText(person.getName());            holder.age.setText(person.getAge());            return convertView;        }        class ViewHolder        {            TextView name;            TextView age;        }    }

使用封装holder

class MyAdapter extends ArrayAdapter<Person>{        public MyAdapter(Context context, int resource, List<Person> objects)        {            super(context, resource, objects);        }        @Override        public View getView(int position, View convertView, ViewGroup parent)        {            Person person = getItem(position);            CommViewHolder viewHolder = CommViewHolder.get(getContext(), parent, R.layout.item_layout, position,convertView);            viewHolder.setTextView(R.id.name, person.getName()).setTextView(R.id.age, person.getAge());            return viewHolder.getmConvertView();        }    }

1.2.Adapter类封装

1.原始类

class MyAdapter extends ArrayAdapter<Person>    {        public MyAdapter(Context context, int resource, List<Person> objects)        {            super(context, resource, objects);        }        @Override        public View getView(int position, View convertView, ViewGroup parent)        {            Person person = getItem(position);            CommViewHolder viewHolder = CommViewHolder.get(getContext(), parent, R.layout.item_layout, position,                    convertView);            viewHolder.setTextView(R.id.name, person.getName()).setTextView(R.id.age, person.getAge());            return viewHolder.getmConvertView();        }    }

2.封装类

public abstract class CommAdapter<T> extends ArrayAdapter<T>{    private int resourceId;    public CommAdapter(Context context, int resource, List<T> objects)    {        super(context, resource, objects);        this.resourceId = resource;    }    @Override    public View getView(int position, View convertView, ViewGroup parent)    {        CommViewHolder viewHolder = CommViewHolder.get(getContext(), parent, resourceId, position, convertView);        setConvert(viewHolder, getItem(position));        return viewHolder.getmConvertView();    }    public abstract void setConvert(CommViewHolder viewHolder, T t);}

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2.ListViewItem不可点击

2.1.原因

抢占焦点控件抢占了焦点：列如button  checkbox等

2.2.解决方法

方法一：为抢占焦点的控件布局添加：android:focusable="false"；方法二：为整个listview的item布局添加android:descendantFocusability="blocksDescendants"

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3.ListView复用导致内容错乱

3.1.checkBox错误选中效果解决

1.未bean对象添加isChecked属性，更具isChecked属性在adapter中动态设置checkBox是否选中2.在adapter中设置一个记录选中checkbox的list集合；

final CheckBox cb = viewHolder.getView(R.id.cb);                cb.setChecked(false);                if(mPos.contains(viewHolder.getPosition()))                {                    cb.setChecked(true);                }                cb.setOnClickListener(new OnClickListener()                {                    @Override                    public void onClick(View v)                    {                        Log.d("guxuewu", "点击了cb");                        if(cb.isChecked())                        {                            mPos.add(viewHolder.getPosition());                        }                        else                        {                            //希望执行remove object方法，所以进行强转                            mPos.remove((Integer) viewHolder.getPosition());                        }                    }                });