android - ArrayAdapter 文本和图像

Question

在我的 Activity 中，我实现了一个列表，其中包含一些文件的名称。 每个列表的项目都引用一个布局，我想在其中显示图像的名称和引用图像的缩略图。我可以使用 ArrayAdapter 显示名称，但我不知道如何插入图像缩略图。 所有引用的图像都保留在 sd_card 中，我有它们的路径。 这是单行布局:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:orientation="horizontal" >

<ImageView
    android:id="@+id/imageView"
    android:layout_width="36dp"
    android:layout_height="wrap_content"
    android:src="@drawable/btn_nav_background_default" />

<TextView
    android:id="@+id/titoloTv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceMedium" />

</LinearLayout>

和 Activity 的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

<Button
    android:id="@+id/creaButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="Crea una nuova realtà aumentata" />

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="Ar già create"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<ListView
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >


</ListView>

</LinearLayout>

和 Activity 代码固有的适配器。

    ArrayAdapter<?> arrayAdapter = new ArrayAdapter<String>(this,R.layout.row,R.id.titoloTv,targetName);
    listView.setAdapter(arrayAdapter);

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {  
           @Override  
           public void onItemClick(AdapterView<?> adapter, final View componente, int pos, long id){

...................            
           } 

    }); 

我正在尝试使用它，但无法正常工作。

    String tempTarget;
    List<Map<String,Object>> data = new ArrayList<Map<String,Object>>();

   for(int i = 0; i<ARelements.size();i++){
        Element ar = arIterator.next();

        Map<String,Object> map = new HashMap<String,Object>(2);
        tempTarget = ar.getAttributeValue("TARGET");
        thumbnailBitmap = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(tempTarget), THUMBSIZE, THUMBSIZE);
        map.put("thumbnail", thumbnailBitmap);
        map.put("titolo", tempTarget);
        data.add(map);
    }
   arIterator= null;

   SimpleAdapter simpleAdapter = new SimpleAdapter(this,data,R.layout.row,new String[] {"thumbnail","titolo"},new int[] {R.id.imageView, R.id.titoloTv});


    listView.setAdapter(simpleAdapter);

Answer 1

您需要实现自定义数组适配器并在适配器中指定 ImageView 和 TextView 布局/id。

类似于:

  public class CustomListViewAdapter extends ArrayAdapter<RowItem> {


    Context context;

    public CustomListViewAdapter(Context context, int resourceId, //resourceId=your layout
            List<RowItem> items) {
        super(context, resourceId, items);
        this.context = context;
    }

    /*private view holder class*/
    private class ViewHolder {
        ImageView imageView;
        TextView txtTitle;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;
        RowItem rowItem = getItem(position);

        LayoutInflater mInflater = (LayoutInflater) context
                .getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.list_item, null);
            holder = new ViewHolder();
            holder.txtTitle = (TextView) convertView.findViewById(R.id.title);
            holder.imageView = (ImageView) convertView.findViewById(R.id.icon);
            convertView.setTag(holder);
        } else
            holder = (ViewHolder) convertView.getTag();

        holder.txtTitle.setText(rowItem.getTitle());
        holder.imageView.setImageResource(rowItem.getImageId());

        return convertView;
    }
}  

然后:

listView = (ListView) findViewById(R.id.list);
        CustomListViewAdapter adapter = new CustomListViewAdapter(this,
                R.layout.list_item, rowItems);
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(this);
    }


@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
        long id) {
    Toast toast = Toast.makeText(getApplicationContext(),
        "Item " + (position + 1) + ": " + rowItems.get(position),
        Toast.LENGTH_SHORT);
    toast.show();
}  

对于 ListView(s) 及其自定义实现，也请参阅扩展其他适配器:
例如。 http://theopentutorials.com/tutorials/android/listview/android-custom-listview-with-image-and-text-using-arrayadapter/