讀取系統相簿為空的問題，今天遇到過了，找到了解決辦法，寫出來記錄一下

關於個別手機讀取到相簿為空，可能的原因是系統版本問題，4.4系統在獲取系統返回的相簿的url的時候，有可能出現為null的問題，解決辦法來自網上

/** 
	 * Get a file path from a Uri. This will get the the path for Storage Access 
	 * Framework Documents, as well as the _data field for the MediaStore and 
	 * other file-based ContentProviders. 
	 * 
	 * @param context The context. 
	 * @param uri The Uri to query. 
	 * @author paulburke 
	 */  
	public static String getPath(final Context context, final Uri uri) {  
	  
	    final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;  
	  
	    // DocumentProvider  
	    if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {  
	        // ExternalStorageProvider  
	        if (isExternalStorageDocument(uri)) {  
	            final String docId = DocumentsContract.getDocumentId(uri);  
	            final String[] split = docId.split(":");  
	            final String type = split[0];  
	  
	            if ("primary".equalsIgnoreCase(type)) {  
	                return Environment.getExternalStorageDirectory() + "/" + split[1];  
	            }  
	  
	            // TODO handle non-primary volumes  
	        }  
	        // DownloadsProvider  
	        else if (isDownloadsDocument(uri)) {  
	  
	            final String id = DocumentsContract.getDocumentId(uri);  
	            final Uri contentUri = ContentUris.withAppendedId(  
	                    Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));  
	  
	            return getDataColumn(context, contentUri, null, null);  
	        }  
	        // MediaProvider  
	        else if (isMediaDocument(uri)) {  
	            final String docId = DocumentsContract.getDocumentId(uri);  
	            final String[] split = docId.split(":");  
	            final String type = split[0];  
	  
	            Uri contentUri = null;  
	            if ("image".equals(type)) {  
	                contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;  
	            } else if ("video".equals(type)) {  
	                contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;  
	            } else if ("audio".equals(type)) {  
	                contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;  
	            }  
	  
	            final String selection = "_id=?";  
	            final String[] selectionArgs = new String[] {  
	                    split[1]  
	            };  
	  
	            return getDataColumn(context, contentUri, selection, selectionArgs);  
	        }  
	    }  
	    // MediaStore (and general)  
	    else if ("content".equalsIgnoreCase(uri.getScheme())) {  
	        return getDataColumn(context, uri, null, null);  
	    }  
	    // File  
	    else if ("file".equalsIgnoreCase(uri.getScheme())) {  
	        return uri.getPath();  
	    }  
	  
	    return null;  
	}  
	  
	/** 
	 * Get the value of the data column for this Uri. This is useful for 
	 * MediaStore Uris, and other file-based ContentProviders. 
	 * 
	 * @param context The context. 
	 * @param uri The Uri to query. 
	 * @param selection (Optional) Filter used in the query. 
	 * @param selectionArgs (Optional) Selection arguments used in the query. 
	 * @return The value of the _data column, which is typically a file path. 
	 */  
	public static String getDataColumn(Context context, Uri uri, String selection,  
	        String[] selectionArgs) {  
	  
	    Cursor cursor = null;  
	    final String column = "_data";  
	    final String[] projection = {  
	            column  
	    };  
	  
	    try {  
	        cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,  
	                null);  
	        if (cursor != null && cursor.moveToFirst()) {  
	            final int column_index = cursor.getColumnIndexOrThrow(column);  
	            return cursor.getString(column_index);  
	        }  
	    } finally {  
	        if (cursor != null)  
	            cursor.close();  
	    }  
	    return null;  
	}  
	  
	  
	/** 
	 * @param uri The Uri to check. 
	 * @return Whether the Uri authority is ExternalStorageProvider. 
	 */  
	public static boolean isExternalStorageDocument(Uri uri) {  
	    return "com.android.externalstorage.documents".equals(uri.getAuthority());  
	}  
	  
	/** 
	 * @param uri The Uri to check. 
	 * @return Whether the Uri authority is DownloadsProvider. 
	 */  
	public static boolean isDownloadsDocument(Uri uri) {  
	    return "com.android.providers.downloads.documents".equals(uri.getAuthority());  
	}  
	  
	/** 
	 * @param uri The Uri to check. 
	 * @return Whether the Uri authority is MediaProvider. 
	 */  
	public static boolean isMediaDocument(Uri uri) {  
	    return "com.android.providers.media.documents".equals(uri.getAuthority());  
	}  
 

例子

			Uri uri = data.getData();
			FileInputStream fis = new FileInputStream(getPath(getBaseContext(),uri));