如何在列表视图中显示存储在SD卡特定位置的图像

Question

我创建了一个应用程序,其中我使用SPenSDK使用canvasView创建图像.一旦我在画布视图中创建图像,我将图像保存在SD卡"/ mnt/sdcard/SmemoExample"位置.现在我想在我的ListView中显示存储在这里的所有图像"/ mnt/sdcard/SmemoExample".

但我无法找到任何解决方案.所以请帮助解决这个问题.如果可能的话,举个例子.

List_view.xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView
    android:id="@+id/list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" 
    android:layout_weight="1"/>
<Button
    android:id="@+id/button1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" 
    android:text="Clear Cache"/>
</LinearLayout>

item.xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<ImageView
  android:id="@+id/image"
  android:layout_width="50dip"
  android:layout_height="50dip" android:src="@drawable/ic_launcher"   android:scaleType="centerCrop"/>
<TextView
  android:id="@+id/text"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:layout_weight="1" android:layout_gravity="left|center_vertical" android:textSize="20dip" android:layout_marginLeft="10dip"/>
</LinearLayout>

java代码

public class ListActivity extends Activity
{
private String[] mFileStrings;

private File[] listFile;

ListView list;

ImageAdapter adapter;

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

     File file = new File(CanvasActivity.DEFAULT_APP_IMAGEDATA_DIRECTORY);

     if (file.isDirectory())
     {
         listFile = file.listFiles();
         mFileStrings = new String[listFile.length];

         for (int i = 0; i < listFile.length; i++)
         {
             mFileStrings[i] = listFile[i].getAbsolutePath();
         }
     }

     list = (ListView) findViewById(R.id.list);
     adapter = new ImageAdapter(this, mFileStrings);
     list.setAdapter(adapter);
}

public class ImageAdapter extends BaseAdapter 
{
    private Activity activity;
    private String[] data;
    private LayoutInflater inflater=null;
    public ImageLoader imageLoader; 

    public ImageAdapter(Activity a, String[] d) 
    {
        activity = a;
        data=d;
        inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        imageLoader=new ImageLoader(activity.getApplicationContext());
    }

    public int getCount() {
        return data.length;
    }

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

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

    public View getView(int position, View convertView, ViewGroup parent) {
        View vi=convertView;
        if(convertView==null)
            vi = inflater.inflate(R.layout.item, null);

        TextView text=(TextView)vi.findViewById(R.id.text);;
        ImageView image=(ImageView)vi.findViewById(R.id.image);
        text.setText("item "+position);
        imageLoader.DisplayImage(data[position], image);
        return vi;
    }
}

}

Answer 1

答案是供上述问题及其他答案参考.

只需看看LazyList项目.现在我们对它进行一些修改..

MainActivity.java

private String[] mFileStrings;
private File[] listFile;

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

        File file = new File("<Directory path from sdcard>");

        if (file.isDirectory())
        {
            listFile = file.listFiles();
            mFileStrings = new String[listFile.length];

            for (int i = 0; i < listFile.length; i++)
            {
                mFileStrings[i] = listFile[i].getAbsolutePath();
            }
        }

        list = (ListView) findViewById(R.id.list);
        adapter = new LazyAdapter(this, mFileStrings);
        list.setAdapter(adapter);

        Button b = (Button) findViewById(R.id.button1);
        b.setOnClickListener(listener);
    }

在ImageLoader.java中

private Bitmap getBitmap(String url)
    {
        File f = new File(url);

        //from SD cache
        Bitmap b = decodeFile(f);
        if (b != null)
        {
            return b;
        }
        return null;
    }