Android Uri和文件路径互相转换的实例代码

在项目中需要用到将uri转换为绝对路径，在网上找到一个方法，做个笔记

网上有不少方法，但是有的对4.4后的版本无效，这里的方法可以在4.4之后的版本将uri转换为绝对路径

public class getpathfromuri { 
  /** 
   * 专为android4.4设计的从uri获取文件绝对路径 
   */ 
  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]; 
        } 
      } 
      // 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()); 
  } 
} 

绝对路径转uri比较简单

以绝对路径创建一个file对象，然后调用

uri.fromfile(file)

以上所述是小编给大家介绍的android uri和文件路径互相转换的实例代码，希望对大家有所帮助