如何從android中的SD卡獲取指定的圖像？

Question

我能夠顯示從SD卡到網格的所有圖像，但如何顯示從SD卡只有指定的圖像到Android的網格。任何人都可以幫忙嗎？

Answer 1

/** 
* Loads images from SD card. 
* @author padma kumar 
*/ 
public class LoadImagesFromSDCardActivity extends Activity implements 
OnItemClickListener { 

    /** 
    * Grid view holding the images. 
    */ 
    private GridView sdcardImages; 
    /** 
    * Image adapter for the grid view. 
    */ 
    private ImageAdapter imageAdapter; 
    /** 
    * Display used for getting the width of the screen. 
    */ 
    private Display display; 

    /** 
    * Creates the content view, sets up the grid, the adapter, and the click listener. 
    * 
    * @see android.app.Activity#onCreate(android.os.Bundle) 
    */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState);   
     // Request progress bar 
     requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS); 
     setContentView(R.layout.sdcard); 

     display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay(); 

     setupViews(); 
     setProgressBarIndeterminateVisibility(true); 
     loadImages(); 
    } 

    /** 
    * Free up bitmap related resources. 
    */ 
    protected void onDestroy() { 
     super.onDestroy(); 
     final GridView grid = sdcardImages; 
     final int count = grid.getChildCount(); 
     ImageView v = null; 
     for (int i = 0; i < count; i++) { 
      v = (ImageView) grid.getChildAt(i); 
      ((BitmapDrawable) v.getDrawable()).setCallback(null); 
     } 
    } 
    /** 
    * Setup the grid view. 
    */ 
    private void setupViews() { 
     sdcardImages = (GridView) findViewById(R.id.sdcard); 
     sdcardImages.setNumColumns(display.getWidth()/95); 
     sdcardImages.setClipToPadding(false); 
     sdcardImages.setOnItemClickListener(LoadImagesFromSDCardActivity.this); 
     imageAdapter = new ImageAdapter(getApplicationContext()); 
     sdcardImages.setAdapter(imageAdapter); 
    } 
    /** 
    * Load images. 
    */ 
    private void loadImages() { 
     final Object data = getLastNonConfigurationInstance(); 
     if (data == null) { 
      new LoadImagesFromSDCard().execute(); 
     } else { 
      final LoadedImage[] photos = (LoadedImage[]) data; 
      if (photos.length == 0) { 
       new LoadImagesFromSDCard().execute(); 
      } 
      for (LoadedImage photo : photos) { 
       addImage(photo); 
      } 
     } 
    } 
    /** 
    * Add image(s) to the grid view adapter. 
    * 
    * @param value Array of LoadedImages references 
    */ 
    private void addImage(LoadedImage... value) { 
     for (LoadedImage image : value) { 
      imageAdapter.addPhoto(image); 
      imageAdapter.notifyDataSetChanged(); 
     } 
    } 

    /** 
    * Save bitmap images into a list and return that list. 
    * 
    * @see android.app.Activity#onRetainNonConfigurationInstance() 
    */ 
    @Override 
    public Object onRetainNonConfigurationInstance() { 
     final GridView grid = sdcardImages; 
     final int count = grid.getChildCount(); 
     final LoadedImage[] list = new LoadedImage[count]; 

     for (int i = 0; i < count; i++) { 
      final ImageView v = (ImageView) grid.getChildAt(i); 
      list[i] = new LoadedImage(((BitmapDrawable) v.getDrawable()).getBitmap()); 
     } 

     return list; 
    } 
    /** 
    * Async task for loading the images from the SD card. 
    */ 
    class LoadImagesFromSDCard extends AsyncTask<Object, LoadedImage, Object> { 

     /** 
     * Load images from SD Card in the background, and display each image on the screen. 
     * 
     * @see android.os.AsyncTask#doInBackground(Params[]) 
     */ 
     @Override 
     protected Object doInBackground(Object... params) { 
      //setProgressBarIndeterminateVisibility(true); 
      Bitmap bitmap = null; 
      Bitmap newBitmap = null; 
      Uri uri = null;    

      // Set up an array of the Thumbnail Image ID column we want 
      String[] projection = {MediaStore.Images.Thumbnails._ID}; 
      // Create the cursor pointing to the SDCard 
      Cursor cursor = managedQuery(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, 
        projection, // Which columns to return 
        null,  // Return all rows 
        null,  
        null); 
      int columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID); 
      int size = cursor.getCount(); 
      // If size is 0, there are no images on the SD Card. 
      if (size == 0) { 
       //No Images available, post some message to the user 
      } 
      int imageID = 0; 
      for (int i = 0; i < size; i++) { 
       cursor.moveToPosition(i); 
       imageID = cursor.getInt(columnIndex); 
       uri = Uri.withAppendedPath(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, "" + imageID); 
       try { 
        bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri)); 
        if (bitmap != null) { 
         newBitmap = Bitmap.createScaledBitmap(bitmap, 70, 70, true); 
         bitmap.recycle(); 
         if (newBitmap != null) { 
          publishProgress(new LoadedImage(newBitmap)); 
         } 
        } 
       } catch (IOException e) { 
        //Error fetching image, try to recover 
       } 
      } 
      cursor.close(); 
      return null; 
     } 
     /** 
     * Add a new LoadedImage in the images grid. 
     * 
     * @param value The image. 
     */ 
     @Override 
      public void onProgressUpdate(LoadedImage... value) { 
      addImage(value); 
     } 
     /** 
     * Set the visibility of the progress bar to false. 
     * 
     * @see android.os.AsyncTask#onPostExecute(java.lang.Object) 
     */ 
     @Override 
     protected void onPostExecute(Object result) { 
      setProgressBarIndeterminateVisibility(false); 
     } 
    } 

    /** 
    * Adapter for our image files. 
    */ 
    class ImageAdapter extends BaseAdapter { 

     private Context mContext; 
     private ArrayList<LoadedImage> photos = new ArrayList<LoadedImage>(); 

     public ImageAdapter(Context context) { 
      mContext = context; 
     } 

     public void addPhoto(LoadedImage photo) { 
      photos.add(photo); 
     } 

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

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

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

     public View getView(int position, View convertView, ViewGroup parent) { 
      final ImageView imageView; 
      if (convertView == null) { 
       imageView = new ImageView(mContext); 
      } else { 
       imageView = (ImageView) convertView; 
      } 
      imageView.setScaleType(ImageView.ScaleType.FIT_CENTER); 
      imageView.setPadding(8, 8, 8, 8); 
      imageView.setImageBitmap(photos.get(position).getBitmap()); 
      return imageView; 
     } 
    } 

    /** 
    * A LoadedImage contains the Bitmap loaded for the image. 
    */ 
    private static class LoadedImage { 
     Bitmap mBitmap; 

     LoadedImage(Bitmap bitmap) { 
      mBitmap = bitmap; 
     } 

     public Bitmap getBitmap() { 
      return mBitmap; 
     } 
    } 
    /** 
    * When an image is clicked, load that image as a puzzle. 
    */ 
     public void onItemClick(AdapterView<?> parent, View v, int position, long id) {   
     int columnIndex = 0; 
     String[] projection = {MediaStore.Images.Media.DATA}; 
     Cursor cursor = managedQuery(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, 
       projection, 
       null, 
       null, 
       null); 
     if (cursor != null) { 
      columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA); 
      cursor.moveToPosition(position); 
      String imagePath = cursor.getString(columnIndex); 

      FileInputStream is = null; 
      BufferedInputStream bis = null; 
      try { 
       is = new FileInputStream(new File(imagePath)); 
       bis = new BufferedInputStream(is); 
       Bitmap bitmap = BitmapFactory.decodeStream(bis); 
       Bitmap useThisBitmap = Bitmap.createScaledBitmap(bitmap, parent.getWidth(), parent.getHeight(), true); 
       bitmap.recycle(); 
       //Display bitmap (useThisBitmap) 
      } 
      catch (Exception e) { 
       //Try to recover 
      } 
      finally { 
       try { 
        if (bis != null) { 
         bis.close(); 
        } 
        if (is != null) { 
         is.close(); 
        } 
        cursor.close(); 
        projection = null; 
       } catch (Exception e) { 
       } 
      } 
     } 
    } 

}