Question

对于每个具有差异行布局模板的列表视图，我必须创建每个自定义适配器，它们执行相同的操作：加载xml行布局，通过id获取控件（TextView，ImageView等），显示数据...像这样的东西：

public class CommentAdapter extends BaseAdapter {

protected Activity activity;
protected static LayoutInflater layoutInflater = null;  
protected List<Comment> lst;    

public CommentAdapter(Activity activity,  List<Comment> lst){
    this.activity = activity;       
    this.lst = lst;
    layoutInflater = (LayoutInflater)this.activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

public int getCount() {     
    return lst.size();
}

public Object getItem(int position) {   
    return lst.get(position);
}

public long getItemId(int position) {   
    return position;
}

public static class ViewHolder{
    public TextView textName;
    public TextView textComment;
    public ImageView image;
}

public  View getView(int position, View convertView, ViewGroup parent) {
    View v = convertView;
    ViewHolder viewHolder;
    if (v == null) {
        v = layoutInflater.inflate(R.layout.listitem, null);
        viewHolder = new ViewHolder();
        viewHolder.textName = (TextView) v.findViewById(R.id.txtName);
        viewHolder.image = (ImageView) v.findViewById(R.id.icon);
        viewHolder.textComment = (TextView)v.findViewById(R.id.txtComment);
        v.setTag(viewHolder);
    } else {
        viewHolder = (ViewHolder) v.getTag();
    }
    Static.overrideFonts(v);
    viewHolder.image.setBackgroundResource(lst.get(position).Icon);
    viewHolder.textName.setText(lst.get(position).Name);
    viewHolder.textComment.setText(lst.get(position).Comment);

    return v;
}
}

使用多种列表视图（差异行布局模板），我必须创建许多适配器。
所以，问题是我想创建一个模板适配器，它可以是动态加载行xml，基于它的id的地图视图控件（也许使用反射）。行xml布局，控件ID，视图控件将在其他地方定义是否有design pattern，example或framework可以实现此目标？

Answer 1

这样的事似乎可行。我根本没有测试过这个，但理论上你可以用这样的东西来逃避：

public interface Adaptable {
    //Interface that any object you make that should be put in a listview
    //should implement
    public View buildView(View v, LayoutInflater inflater);
    public int getLayoutId();
}

public class MyObject implements Adaptable
    //Just hardcode your layout for this type of object
    public int getLayoutId() {
        return R.layout.myLayout;
    }

    //getView() will pass the recycled view to this method
    //which will handle building the view per this object
    public View buildView(View v, LayoutInflater inflater) {
        if(v == null) {
            v = inflater.inflate(getLayoutId());
            //Other initialization
        } //other initialization

        return v;
    }
}

//Then make the generic adapter that handles anything that implements
//the Adaptable interface
public GenericAdapter implements ListAdapter {
    private LayoutInflater inflater;
    private List<Adaptable> items;
    public GenericAdapter(List<Adaptable> items, Context c) {
        this.items = items;
        inflater = LayoutInflater.from(c);
    }

    //Now, using polymorphism, it should return a correctly built
    //view for whatever object type you've passed in.
    @Override
    public View getView(int pos, View convertView, ViewGroup parent) {
        return items.get(pos).buildView(convertView, inflater);
    }
}

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    List<MyObject> objects = new ArrayList<MyObject>();
    //Fill your list however.

    //get your ListView, then...
    listView.setAdapter(new GenericAdapter(object, this));
}

我可能完全忽略了一些不起作用的原因 - 我在五分钟内输入了这个。从理论上讲，我认为它会起作用。

Answer 2

我尝试了 kcoppock 的方式，但我做的更复杂一些。
首先，我创建一个ViewHolder，它可以使用注释与视图id进行映射。

public class MobileViewHolder {

    @InvokeView(viewId = R.id.label)
    public TextView text;

    @InvokeView(viewId = R.id.logo)
    public ImageView image;
}

然后，我可以使用reflect：

在ViewHolder中使用view id映射字段

   Field fs[] = viewHolder.getClass().getFields();
        for (Field f : fs) {
            InvokeView a = (InvokeView)f.getAnnotation(InvokeView.class);
            int id = a.viewId();
            f.set(viewHolder, v.findViewById(id));

    }

之后，我只是将实体中的数据绑定到ViewHolder。

  public void mappingData(MobileViewHolder viewHolder, Mobile entity) {
    viewHolder.text.setText(entity.name);
    viewHolder.image.setBackgroundResource(entity.image);
}

结论：这样，对于多种列表视图哪个区别行布局模板，我只需要4件事：

行xml文件
ViewHolder：定义视图控件和视图属性
实体
项目视图：在ViewHolder和Entity之间扩展BaseView和映射逻辑数据。

以下是我测试的source code样本：）

android中用于多种listview布局行的通用适配器

2 个答案: