Android GridView显示SD卡的图片

<GridViewxmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/gridview"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:numColumns="auto_fit"

    android:verticalSpacing="10dp"

    android:horizontalSpacing="10dp"

    android:columnWidth="90dp"

    android:stretchMode="columnWidth"

    android:gravity="center"

/> 

<RelativeLayout

        xmlns:android="http://schemas.android.com/apk/res/android"

        android:layout_height="wrap_content"

         android:paddingBottom="4dip"android:layout_width="fill_parent">

         <TextView

         android:layout_width="wrap_content"

         android:layout_height="wrap_content"

         android:id="@+id/textid"/>

         <ImageView

              android:layout_height="wrap_content"

              android:id="@+id/ItemImage"

               android:layout_width="wrap_content"

              android:layout_centerHorizontal="true">

         </ImageView>

</RelativeLayout>  

 public class FileimageActivity extends Activity {

       private static final String TAG = "Fileimage";

       private List<HashMap<String, String>> list;

       private ContentResolver cr;

       private List<ImageView> imageViews = null;

       HashMap<String,Object> hashMap;

       public Bitmap bitmap;

       public Bitmap newBit;

     public void onCreate(Bundle savedInstanceState)

 　　{

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        findimagepath();

     }

     public void findimagepath()

      GridViewgridView=(GridView)findViewById(R.id.gridview);

      list=newArrayList<HashMap<String,String>>();

      cr=getContentResolver();

      String[]imagedata={Thumbnails._ID,Thumbnails.IMAGE_ID,Thumbnails.DATA};//找到image

      Cursorcursor=cr.query(Thumbnails.EXTERNAL_CONTENT_URI, imagedata, null,

                    null,null);                                                                                                         //利用游标找image

      String[] from = { "image_id", "path" };

      int[] to = { R.id.textid, R.id.ItemImage };                                                               //在imageView.xml的布局中

      getColumnData(cursor);

      ListAdapteradapter = new picview(this, list, R.layout.imageitem,

                            from,to);

      gridView.setAdapter(adapter);

    }

//找到image的path，再放进list里。

  private void getColumnData(Cursor cur)

 {

     if(cur.moveToFirst())

     {

           int_id;

           intimage_id;

           Stringimage_path;

           int_idColumn = cur.getColumnIndex(Thumbnails._ID);

           intimage_idColumn = cur.getColumnIndex(Thumbnails.IMAGE_ID);

           intdataColumn = cur.getColumnIndex(Thumbnails.DATA);

           Log.i(TAG, String.valueOf(_idColumn)) ;

           do{

                            //Get the field values

                            _id= cur.getInt(_idColumn);

                            image_id= cur.getInt(image_idColumn);

                            image_path= cur.getString(dataColumn);

                            //Do something with the values.

                            //Log.i(TAG, _id + " image_id:" + image_id + " path:"

                            //+ image_path + "---");

                            HashMap<String,String> hash = new HashMap<String, String>();

                            hash.put("image_id",image_id + "");

                            hash.put("path",image_path);

                            list.add(hash);

                     }

                     while(cur.moveToNext());

              }

       }

          //很多时候GridView 是利用BaseAdapter来显示图片更多，BaseAdapter的图片资源多少来自drawable的资源。不过其实用SimpleAdapter就已经可以，

        //重点是SimpleAdapter中有setViewImage这个方法。

        class picview extends SimpleAdapter{

　　　　     public picview(Context context, List<? extends Map<String, ?>> data,

                            intresource, String[] from, int[] to) {

                     super(context,data, resource, from, to);

             }

              /*

               * Called by bindView() to set theimage for an ImageView but only if there is no existing ViewBinder or i

               * f the existing ViewBinder cannothandle binding to an ImageView.

               *  By default, the value will betreated as an image resource.

               *  If the value cannot be used asan image resource, the value is used as an image Uri.

               *   This method is called insteadof setViewImage(ImageView, int)

               * if the supplied data is not an int orInteger.

               * @ value为image的地址 即为path

               * Parameters

               * v  ImageView to receive an image

           value  the value retrieved from the data set

               */

              public void setViewImage(ImageView v, String value)

              {

                     try

                     {

                            FileInputStreamfis = new FileInputStream(value);

                            BufferedInputStreambis = new BufferedInputStream(fis);

                            bitmap= BitmapFactory.decodeStream(bis);

                            newBit= Bitmap.createScaledBitmap(bitmap, , , false);

                            v.setImageBitmap(newBit);

                            bis.close();

                            fis.close();

                     }

                       catch (Exceptione)

                     {

                            Log.e(TAG,e.toString());

                            v.setImageURI(Uri.parse(value));

                     }

              }

       }

}