android如何获取sd卡中的特定图像

Question

我想要sdcard中的任何一个图像。 我只知道image的名字。 但我如何检索我的程序（包括路径）内的特定图像。也可以转换成bitmap或存储在位图变量 我该怎么做？ 谢谢

Answer 1

在这里，你可以显示SD卡的所有图像，当你点击其中一个，你选择图片的路径：

try { 
     // 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 = managedQuery(
       MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, 
       projection, // Which columns to return 
       null, // Return all rows 
       null, MediaStore.Images.Thumbnails.IMAGE_ID); 


     // Get the column index of the Thumbnails Image ID 
     columnIndex = cursor 
       .getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID); 

     GridView sdcardImages = (GridView) findViewById(R.id.gallary); 
     sdcardImages.setAdapter(new ImageAdapter(this)); 

     // Set up a click listener 
     sdcardImages.setOnItemClickListener(new OnItemClickListener() { 
      public void onItemClick(AdapterView parent, View v, 
        int position, long id) { 
       // Get the data location of the image 
       String[] projection = { MediaStore.Images.Media.DATA }; 
       cursor = managedQuery(
         MediaStore.Images.Media.EXTERNAL_CONTENT_URI, 
         projection, // Which columns to return 
         null, // Return all rows 
         null, null); 
       columnIndex = cursor 
         .getColumnIndexOrThrow(MediaStore.Images.Media.DATA); 
       cursor.moveToPosition(position); 
       // Get image filename 
       String imagePath = cursor.getString(columnIndex); 
       // Use this path to do further processing, i.e. full screen 
       // display 
      } 
     }); 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 

这里是ImageAdapter：

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

    private Context context; 

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

    public int getCount() { 
     return cursor.getCount(); 
    } 

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

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

    public View getView(int position, View convertView, ViewGroup parent) { 
     ImageView picturesView; 
     if (convertView == null) { 
      picturesView = new ImageView(context); 
      // Move cursor to current position 
      cursor.moveToPosition(position); 
      // Get the current value for the requested column 
      int imageID = cursor.getInt(columnIndex); 
      // Set the content of the image based on the provided URI 
      picturesView.setImageURI(Uri.withAppendedPath(
        MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, "" 
          + imageID)); 
      picturesView.setScaleType(ImageView.ScaleType.FIT_CENTER); 
      picturesView.setPadding(8, 8, 8, 8); 
      picturesView 
        .setLayoutParams(new GridView.LayoutParams(100, 100)); 
     } else { 
      picturesView = (ImageView) convertView; 
     } 
     return picturesView; 
    } 
} 

如果你知道确切的路径和图像名称，您可以通过使用得到Bitmap：

Bitmap bitmap = BitmapFactory.decodeFile("yourImageDirectory" + "yourImageName.png");