Adapter的泛型

宗旨：GetView方法放在具体的Activity/Fragment里面实现，其他的均可以复用

/// <summary>

/// 通用适配器：新建GetViewEvent委托+OnGetView方法，在外部实现，在重写GetView方法中调用

/// </summary>

/// <typeparam name="T"></typeparam>

public class CommonAdapter<T> : BaseAdapter<T>

{

    //要绑定的数据

    private readonly List<T> items;

    //页面上下文

    private readonly Activity context;

    //ListViewItem的布局id

    private readonly int layoutId;

    /// <summary>

    /// 委托

    /// </summary>

    public delegate View GetViewEvent(int position, View convertView, ViewGroup parent, T item, ViewHolder viewHolder);

    /// <summary>

    /// 加载item的View事件

    /// </summary>

    public event GetViewEvent OnGetView;

    public CommonAdapter(Activity context, int layoutId, List<T> items)

    {

        this.context = context;

        this.layoutId = layoutId;

        this.items = items;

    }

    public override T this[int position]

    {

        get { return items[position]; }

    }

    public override int Count

    {

        get { return items.Count; }

    }

    public override long GetItemId(int position)

    {

        return position;

    }

    public override View GetView(int position, View convertView, ViewGroup parent)

    {

        var item = items[position];

        var view = convertView;

        var viewHolder = ViewHolder.Get(context, convertView, parent, layoutId, position);

        if (OnGetView != null)

            return OnGetView(position, convertView, parent, item, viewHolder);

        return view;

    }

}

/// <summary>

/// 通用ViewHolder：保存控件，下拉刷新列表时只重新赋值，不再新建控件（节省内存）

/// Tag属性保证不错位

/// </summary>

public class ViewHolder : Object

{

    private readonly SparseArray<View> views;

    private int position;

    private readonly View ConvertView;

    public ViewHolder(Activity context, ViewGroup parent, int layoutID, int position)

    {

        this.position = position;

        views = new SparseArray<View>();

        ConvertView = context.LayoutInflater.Inflate(layoutID, null);

        ConvertView.Tag = this;

    }

    //单例模式获取对象实例

    public static ViewHolder Get(Activity context, View convertView, ViewGroup parent, int layoutID, int position)

    {

        if (convertView == null)

            return new ViewHolder(context, parent, layoutID, position);

        var holder = (ViewHolder) convertView.Tag;

        holder.position = position;

        return holder;

    }

    public View GetConvertView()

    {

        return ConvertView;

    }

    /// <summary>

    ///  通过ViewID获取控件

    /// </summary>

    /// <typeparam name="T"></typeparam>

    /// <param name="viewId"></param>

    /// <returns></returns>

    public T GetView<T>(int viewId) where T : View

    {

        var view = views.Get(viewId);

        if (view == null)

        {

            view = ConvertView.FindViewById<T>(viewId);

            views.Put(viewId, view);

        }

        return (T) view;

    }

}

MainActivity

protected override void OnCreate(Bundle bundle)

{

    base.OnCreate(bundle);

    SetContentView(Resource.Layout.Main);

    ListView listView = FindViewById<ListView>(Resource.Id.id_lv_main);

    List<Student>  StudentsList =new List<Student>();

    StudentsList.Add(new Student()

    {

        Name = "朱泓霖"

    });

    CommonAdapter<Student > comAdapter =

        new CommonAdapter<Student>(this, Resource.Layout.Item, StudentsList);

    comAdapter.OnGetView += comAdapter_OnGetView;

    listView.Adapter = comAdapter;

}

private View comAdapter_OnGetView(int position, View convertView, ViewGroup parent, Student item, ViewHolder viewHolder)

{

    //通过ViewHolder获取对象并赋值

    viewHolder.GetView<TextView>(Resource.Id.id_tv_title).Text = item.Name;

    return viewHolder.GetConvertView();

}

巴特西

Adapter的泛型

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