Question

在我的活动中，我实现了一个包含某些文件名称的列表。每个列表的项目都指的是我想要显示图像名称和引用图像缩略图的布局。我可以使用ArrayAdapter显示名称，但我不知道如何插入图像缩略图。引用的所有图像都保留在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>

以及活动的布局

<?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>

和活动代码固有的适配器。

    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。

类似的东西：

  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();
}

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

Answer 2

您不一定需要自定义ArrayAdapter，SimpleAdapter将为缩略图/文本组合提供技巧。您可以在HashMap数组中存储缩略图和所需文本的路径，然后使用SimpleAdapter应用它。例如，如果您有5个缩略图+文本和每个的数组：

List<Map<String, Object>> data = new ArrayList<Map<String, Object>>();
for (int i = 0; i < 5; i++) {
            Map<String, Object> datum = new HashMap<String, Object>(2);
            datum.put("thumbnail", thumbnail[i]);
            datum.put("name", text[i]);
            data.add(datum);
        }
YourListViewId.setAdapter(new SimpleAdapter(this, data, R.layout.yoursinglerowlayout, new String[] {"thumbnail","name"}, new int[] {R.id.imageView, R.id.titoloTv}));

Answer 3

首先：您必须将ArrayAdapter更改为BaseAdapter，因为BaseAdapter为您提供了更多的视图灵活性。尝试使用此代码并查看其工作原理：

以下是我从SD卡获取图像并在列表视图中填充的方法

public class GetSdCardContent extends Activity {

    public static Cursor cursor;
    private int columnIndex;
    private File file;
    private String SD_CARD_ROOT;
    ArrayList<String> f = new ArrayList<String>(); 
    File[] listFile;
    ImageAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.sdcard_layout);


        getSdcardImages();


        ListView lv1 = (ListView) findViewById(R.id.sdlistView1);
        adapter = new ImageAdapter();
        lv1.setAdapter(adapter);

    }


    public void getSdcardImages() {
        File file = new File(
                android.os.Environment.getExternalStorageDirectory().getPath(),
                "Pictures");


        if (file.isDirectory()) {
            listFile = file.listFiles();

            for (int i = 0; i < listFile.length; i++) {

                f.add(listFile[i].getAbsolutePath());
                Log.i("FILES:"+"---", f.toString());

            }
        }
    }

这是我正在使用的适配器。它是一个基础适配器，我现在只获得图像。如果您愿意，也可以添加TextView。

    public class ImageAdapter extends BaseAdapter {
        private LayoutInflater mInflater;

        public ImageAdapter() {
            mInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }

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

        public Object getItem(int position) {
            return position;
        }

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

        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder holder;
            if (convertView == null) {
                holder = new ViewHolder();
                convertView = mInflater.inflate(R.layout.custom_listview_items,
                        null);
                holder.imageview = (ImageView) convertView
                        .findViewById(R.id.customimageView1);

                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }

            Bitmap myBitmap = BitmapFactory.decodeFile(f.get(position));
            try {

                holder.imageview.setImageBitmap(getResizedBitmap(myBitmap, 300, 300));
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return convertView;
        }
    }

此方法适用于位图。如果你想调整图像和内容的大小。

    public Bitmap getResizedBitmap(Bitmap bm, int newHeight, int newWidth) {
        int width = bm.getWidth();
        int height = bm.getHeight();
        float scaleWidth = ((float) newWidth) / width;
        float scaleHeight = ((float) newHeight) / height;
        // CREATE A MATRIX FOR THE MANIPULATION
        Matrix matrix = new Matrix();
        // RESIZE THE BIT MAP
        matrix.postScale(scaleWidth, scaleHeight);

        // "RECREATE" THE NEW BITMAP
        Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, false);
        return resizedBitmap;
    }
    class ViewHolder {
        ImageView imageview;

    }
}

最后一部分：两个布局。

一：项目布局。

<?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" >

    <ImageView
        android:id="@+id/customimageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/bluebutton" />

</LinearLayout>

第二：主要布局。（ListView中）

<?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" >

     <ListView
        android:id="@+id/sdlistView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView> 


</LinearLayout>

希望这会给你一些帮助.. :)

Answer 4

我已经使用这个类解决了它

public class ExtendedSimpleAdapter extends SimpleAdapter{
List<HashMap<String, Object>> map;
String[] from;
int layout;
int[] to;
Context context;
LayoutInflater mInflater;
public ExtendedSimpleAdapter(Context context, List<HashMap<String, Object>> data,
        int resource, String[] from, int[] to) {
    super(context, data, resource, from, to);
    layout = resource;
    map = data;
    this.from = from;
    this.to = to;
    this.context = context;
}


@Override
public View getView(int position, View convertView, ViewGroup parent) {
mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
return this.createViewFromResource(position, convertView, parent, layout);
}

private View createViewFromResource(int position, View convertView,
    ViewGroup parent, int resource) {
View v;
if (convertView == null) {
    v = mInflater.inflate(resource, parent, false);
} else {
    v = convertView;
}

this.bindView(position, v);

return v;
}


private void bindView(int position, View view) {
final Map dataSet = map.get(position);
if (dataSet == null) {
    return;
}

final ViewBinder binder = super.getViewBinder();
final int count = to.length;

for (int i = 0; i < count; i++) {
    final View v = view.findViewById(to[i]);
    if (v != null) {
        final Object data = dataSet.get(from[i]);
        String text = data == null ? "" : data.toString();
        if (text == null) {
            text = "";
        }

        boolean bound = false;
        if (binder != null) {
            bound = binder.setViewValue(v, data, text);
        }

        if (!bound) {
            if (v instanceof Checkable) {
                if (data instanceof Boolean) {
                    ((Checkable) v).setChecked((Boolean) data);
                } else if (v instanceof TextView) {
                    // Note: keep the instanceof TextView check at the bottom of these
                    // ifs since a lot of views are TextViews (e.g. CheckBoxes).
                    setViewText((TextView) v, text);
                } else {
                    throw new IllegalStateException(v.getClass().getName() +
                            " should be bound to a Boolean, not a " +
                            (data == null ? "<unknown type>" : data.getClass()));
                }
            } else if (v instanceof TextView) {
                // Note: keep the instanceof TextView check at the bottom of these
                // ifs since a lot of views are TextViews (e.g. CheckBoxes).
                setViewText((TextView) v, text);
            } else if (v instanceof ImageView) {
                if (data instanceof Integer) {
                    setViewImage((ImageView) v, (Integer)     data);                            
                } else if (data instanceof Bitmap){
                    setViewImage((ImageView) v, (Bitmap)data);
                } else {
                    setViewImage((ImageView) v, text);
                }
            } else {
                throw new IllegalStateException(v.getClass().getName() + " is not a " +
                        " view that can be bounds by this SimpleAdapter");
            }
        }
    }
}
}



private void setViewImage(ImageView v, Bitmap bmp){
v.setImageBitmap(bmp);
}



}

ArrayAdapter文本和图像

4 个答案: